@@MrKennyanders idk who mad mike is but if they know the weaknesses just as Robs experiments maybe you can't hold mazda accountable 100% but I would hold them a certain percentage accountable if they don't make the changes neeeded. they can come and quote you millions for R&D costs well it's already R&D'd just Do it and test it hence saving millions and gaining millions in sales if it works in favor. lol. Just a Random rant over here.
Yup. I know for a fact I will never own a rotary. I don't really even care about them, I am a chevy guy through and through. Yet, here I am, and here I shall remain.
It’s an utter shame how the engineering world gave up on the Rotary engine so quickly. Had they gotten the same attention piston engines got, who knows where they’d be today. People like you are putting in the effort to bring it back!
@@sonyx5332 depends, do it yourself? About 200$ worth of equipment 20$ worth of parts And 1500$ worth of inexperienced balls To get someone else to do it? Anywhere from 200-2000
@@alexzanderroberts995 I raced rotary engine for years and held all motor world record. The downfall of the rotary is emissions and fuel economy. Great reliable light weight engines that make tons of power but they are not fuel efficient and can't meet the strict emission laws that all the tree huggers make these days.
THIS! Sad part is, so many in the rotary community will deny and call you a liar because they don't want their customers to be wise and save money. Keep it up! So glad I'm learning this before I do my inevitable rebuild
They can't, cuz they are not the ones that made 1500HP to all 4 wheels and chained their tube chassis 4rotor rx7 to containers at the hoonigan burn yard and did a sick ass burnout. Rob knew first he had to prove the reliability aspect of his engine's. Now that he did, he can talk shit about the bullshitters.
@@Toxic88088 Looks like, because he's willing to risk breaking it, Rob's learning more about where and why it breaks. Watching the quad rotor dance on the end of that chain, and seeing the loads it was generating, was fantastic.
I love the fact that Dahm is shitting on years upon years of shite mechanics (which are responsible for many cool cars having bad reputations in US, not just an engine, because of their incompetence) but also the "boutique" gate keepers. Rotaries are here to stay. Every day there's new rotary content and more and more people who learn that the bullshit is just that, bullshit.
Its a weird balance because ive learned alot from alot of shitty mechanics. But half truths and poor customer service capped their abilities. I have the opportunity to do more R&D than most enthusiasts and i LOVE cutting through the smoke and mirrors. If i can make 1000hp on a clapped to all fuck out 3 rotor then it cant be that secretive. Setting my sights on HP density next. 1000 hp 2 rotor. Then apply that to the 4 rotor and push the envelop
@@RobDahm shitty mechanics show us where corners can be cut. If my mechanics car doesn’t stink of who knows what, and doesn’t have random switches in it to keep its rusty junk ass going I probably can’t afford them to begin with. But I won’t want to take my car to them because when I ask for dodgy work they won’t touch it.
We used to remove 3 thou off each side entirely not just the tips. We also machined the actual faces down on the rotors as well. You’d be surprised how different each casting is and how unevenly material removal was on those faces. Ran 13b’s with 58psi making 980+whp pretty much indefinitely for multiple drag seasons on customer cars. Just clearance and balance and run a good studded block and they’ll run forever. There’s no real secrets to be had or magic port work that hasn’t already been tried over the past 50yrs.
When I discuss Rotary engines vs Piston engines with folks I always point out the difference in engineering efforts. The overall effort (engineering/testing/etc) to improve the piston engine absolutely dwarfs the Rotary engine. I often wonder what may have been if the Rotary had even 1/10th of the same effort applied to it. Great video.
I often wonder the same thing. There are definitely issues with rotary engines, but I doubt that any of those are fundamental flaws with the concept. Just look at what we can do now as opposed to 50 years ago. Probably ten times as power dense (more power in 3 small cylinders vs 8 big ones), while also being a hundred times cleaner. If those problem solving skills could have been partly applied to rotaries? I think some really cool technology could have come out of it. Sadly, with the future moving away from combustion, its unlikely that it will ever get that kind of attention.
@@aggonzalezdc They are fundamental flaws though. The power density isn't even that great. If you measure a 4 stroke engine like a rotary the displace is half or you can double the size of the rotary. That's because a rotary fires it's full displace for every rev of the crank while a 4 stroke only fires half it's displacement. So the 1.3L is really a 2.6L and I will assure you a 13b is no match for say a RB26 with similar type builds.
@Mike Woodfill No they don't even the skyactiv rotary put up disappointing numbers, new iterations will too. Plus the clock has run out for them, the sun is setting on all ICE engines.
Love the fact you’ve gone from starting with a basic knowledge of rotaries, to fully fabricating parts and successfully building and tuning them to 1000+hp. Dahm, take a fucking bow my friend.
The first new car my family had was a 1972 Mazda RX2. I remember how smooth that engine was and it never left my mind. Sadly, the car was totaled when it was three weeks old and we replaced it with a larger car. I thought that the rotary engine would be the thing of the future at the time. Here we are fifty years later and this video is a blast from the past for me. Well done, sir. You have earned another subscriber.
TLDW: treat your engine like a 2 stroke, E-85 with 2 stroke oil, replace the dowel rods with solid rods, get thicker tension bolts, run the oil through the blocks separately instead of through the single oil hole where the dowel is causing block cracks.
Why 2 stroke oil? Fuel lubricity improvement? How about adding biodiesel instead to improve lubricity? Surpassed every other supplement in a recent HFRR fuel lubricity test.
@@patrick2mail You’ve got to be denser than osmium. You add oil to fuel in a 2-stroke engine because it doesn’t get oil to the rings. You run oil premix in a rotary because you’ve deleted the oil injection system and still need to lubricate the apex seals.
Man, I feel like you glossed over detonation, which is a bug issue for the FD. Detonation will destroy those apex seals and, like mentioned, will destroy the rotor housing and the turbochargers on the way out. Two necessary solutions here that weren't mentioned. First, the stock intercooler for the FD3S is laughably small. A larger intercooler will keep charge air temperature down to reduce the risk of detonation. Also, the factory apex seals come in two pieces. They do slide around and make somewhat of a better seal but machining the rotors to accept a larger 3mm single piece apex seal is a much better option.
Good bit of misdirection in this video. Most all rotaries die from detonation or overheating. Cracks in the housing or dowel are rare unless you are pushing high power on S4 housings. I was also surprised to hear carbon buildup attribute to… coolant? That’s not at all right, it’s due to running rich as hell.
@@wompa164can’t carbon build up also be attributed to not driving the engine right? I’ve heard that higher rpm’s and driving it harder and faster is better for this engine like a Porsche
This has to be one of the most straight up legit gear head engine mod videos I've ever seen. This guy uses science to explain why he does each mod on the engine and not make it sound like hookum. Well done young man!!!
lmao Dahm knows not much to be honest. He's been into rotangs and only just figuring this stuff out now? I don't even own one and knew most of this. If you want actual knowledge look up High performance Academy. There is a reason people are usually popular on youtube: they cater to the lowest common denominator.
@@N4CR homie all you had to tell us is "I don't own one". Maybe you know this stuff in theory but have done nothing to figure it out or help us learn. The lowest common denominator is you
Really interesting vid, I've said this for a long time, tighter fitting components make much stronger motors. As long as clearances arnt silly tight like f1 motors and you warm things ups properly (2 stroke talk there) then your going to avoid so much hassle in the future. High hp builds are difficult, my daily vehicles are usually low tune massive reliability. My toys are high tune lower reliably... but in the same breath if you warm things up and dont just beat on them out the gate then higher performance motors can still give very respectable bang for buck. Thanks for being an inspiration for many years Rob, I'm genuinely glad it's worked out for you. I'm a bike guy through and through but your passion for rotary engines is genuinely inspiring!
Thanks Rob! Sad to say, you probably already have a target on your back. I can't wait to learn about the different compositions of the apex seals. I'm sure most of them are hot-work alloys. I've seen a 160k mile mazda seal under a metallurgical microscope. It's amazing what they did!
Man I just love that you’re just putting all your results and solutions out like this and I bet lots of rotary guys that watched this are making plans to sort out their motors now
This guy is a REAL one!!! In an ocean of confusion and needless upgrades... it's refreshing to get realworld practical guidance with an accompanying explanation of the "WHY" supporting the recommendations!!! A Genius IMHO!!! Thank You for the great videos!!!👍💯🙏
As a tech this is hands down my favorite type of auto content. Diving into the mechanics. Analyzing what can and will go wrong. And then coming up with solutions, that may or may not work. And be able to learn from it and convey that knowledge to others.
I plan on fixing my 2004 Rx 8. She has been sitting for a little bit. I start her up once in a while. Everyone keeps on telling me to swap that boat anchor out and I refuse. ( yes I'm a girl that knows a lot more about rotary then the guys around me ) I've done most of the work on my car. I love 💕 working on cars. Can't wait to pull my engine and see inside and at the same time nervous. It takes a lot of money to rebuild. Good thing im about to start a job. Great Vid by the way. I'm going to prove them all wrong one of these days a rotary can be reliable. Hopefully sooner then later 13B
This is why i watch you Rob over most youtube creators. Informative and clearing up the BS, no one deserves to be ripped off with pointless modifications and i'm glad you are helping the community and enthusiast!
The Wankel Engine has SO much potential. It defies belief that only one company was willing to take the risks to produce it. I remember coming to the exact same conclusion you did about the two-stroke oil. E-85...that's brilliant because it's a little bit counter intuitive. I always wondered why the apex seals would fail...which you explained beautifully. I just had a thought about a maranging stainless steel alloy. Such an alloy actually gets stronger as it gets hotter...up to a certain temperature. You may need some babbit metals alloyed with it to provide proper wear characteristics. You need to study metallurgy on your own. A smart guy like you may come up with the best alloy and solve that issue once and for all. Also, the spring under the apex seal, maybe there's some super unobtanium alloy that will last the useful life of the engine. I think you should focus on the aviation market...once you fix all of the issues. It's a good compromise between a reciprocating engine & gas turbine. The sky is the limit!
If all you care about is compactness and power, then sure there's nothing wrong with Wankels. But if you start needing to follow emissions and efficiency requirements, they start running into the same type of problems that prevent 2-stroke engines from going into mass produced cars. two-stroke oil doesn't burn cleanly, difficulty in implementing valve timing, the fact that the combustion chamber is moving at high speed makes it difficult to burn all the fuel fast enough, limitation in compression ratio.
@@Appletank8 I could be mistaken, but I don’t think the emissions would hold it back in the aviation sector. Of course, leave it to the EPA long enough, and they’ll mandate electric motors for private aircraft.
@@skookapalooza2016 Yes small aircraft generally has less emissions regulations, and is more focused on absolute reliability, though they are finally phasing out leaded fuel for one. Still, a more efficient engine does mean you can fly further on the same tank of gas, so while a well maintained wankel can generally operate pretty reliably, their range would likely be a bit worse.
Wish your channel existed 15 years ago! LOL. I've owned and still am the proud owner of the 7, and on my 6th engine. Went thru tune shops that didn't know what they're doing, and engines that were poorly built. It was funny you mentioned the ripple water mod cuz I had that done to one of my engines, and it blew during tuning 1 week after it was put in the car. I too had serious carbon build up on rotors in one of my engines and a chunk of that came loose which ultimately killed the apex and the engine. Believe it or not, that build was by Amemiya and was only making 500hps. The engine lasted about 4 years and 30,000km. "Too much city driving" was to blame for the carbon buildup, but never thot that was the real reason. What you're doing is super awesome and helping rotary lovers globally while fulfilling our dreams at the same time. Good on you, thank you from my heart, and keep up the phenomenal channel! Can't wait to see your next video on apex seals.
Awesome video, I’ve been tempted to buy an RX8 several times, but scared off by all the engine problems I’ve heard about. If I could find a local shop that could do all these mods, then I would seriously consider buying a used RX8
@@ujiltromm7358 He's actually right though. Those Wankel designs have been a lot more susceptible to failure unlike a lot of other engines I have ever seen or heard of due to its low thermal efficiency and unreliability later on. Regardless how hard Mazda tries to improve or come with their own "solutions", how great it might be on gas, or how much less moving parts there are, if a seal on it breaks and coolant starts leaking inside it, that engine is ready to go no matter how hard you try to save it. But if powerplant is your specialty and you like taking engines apart, more power to you. But for me, I need something that gives me the best to both worlds: fuel saving, and reliable engine that will last much longer than 100k miles before a planned overhaul (or worsecase scenario: engine rebuild).
@@EdnovStormbrewer You're looking for the Toyota 4 cylinder or the Toyota 4 cylinder hybrid. Most reliable for up to 300K miles with regular oil changes.
Sounds like the ideal rotary engine has two oil systems, the lubrication system and the combustion chamber system. The dowel tie rod issue I would be reluctant to put a one piece sized steel element through an aluminum block due to thermal expansion geometry. If anything you put a hex-shafted steel fastener through a shrink fit hex-broached aluminum dowel body. That allows your aluminum parts to grow together but retains decent unity between the steel and aluminum parts. Sounds like an expensive machining job though.
Same thoughts, which made me think why not add locating/locking/torsion pins. I would make temporary punch pins to put into one side where initial placement holes would be made, assemble the parts and whack with a rubber mallet or tap with a copper one. Drill out adjacent pin holes and you have a much sturdier engine assembly with pins holding rotationary forces instead of relying on bolts having two jobs.
The only thing I would change is to increase the thread diameter to reduce stress concentration at the thread base and reduce allowable strain in the threaded section. I don't believe the thermal expansion and contraction is anything to be concerned about as these are non interference fit parts and will have clearance to work at operational temperatures. I also do not see any advantage to having a hex shaft section over a round, can you explain your thinking around that please? I would have thought an Al dowel broached hex, pre-stained and subjected to static and dynamic loads would have high levels of stress concentration and prone to cracking, cost not being a consideration in any case
Why do the "blocks" have to even be aluminum? Not like a big ole large block iron muscle car motor....fairly small casting compared to those? what if they were NC machined from billet steel or iron? OR for the aluminum blocks what if the dowels were also made of aluminum like the block but with a machined hole the entire length to accommodate a splined steel rod pressed all the way through it!!?? Idk if splined is the right word but I picture a bunch of sharp ridges all the way around the steel rod the splined running parallel the length of the rod (except where threaded on the ends of course)....the splined diameter would be slightly larger diameter than the inside bore of the aluminum dowels so that when pressed into place it would actually displace material and be totally locked into place with zero slop and yet be able to compensate for your thermal expansion due there actually being expansion space net to each spine? I have seen little dowel pins like that pressed into aluminum just to lock them from spinning but this would be a different goal/application ...just an idea from a non qualified non engineer in case it is dumb for some reason
As a man who does computers and is interested(but relatively young) car guy and hopefully engineer I must say I am impressed. You show stuff what a real tuner shows. You test things, go through trial and error, make notes and document your research. A true engineer and a man of science. You also have a clean way of explaining the reasons and solutions as well as not wasting time or using cheap attention tricks. Must say I'm trully impressed and I'm looking forward to seeing more
I love how you're changing the game for rotary engines. As a mechanic who has always hated how engineers cut corners to reduce costs it's so refreshing to see all the bs cut out and someone with the ability to redesign something the way it should be designed. Keep up the good work, I look forward to these more technical videos
The mistakes made by Mazda are being undone by the dudes at LIQUIDPISTON They basically just flipped the design of the Mazda rotary engine and made a far superior engine. (They’re a pretty small team of engineers) They operate here in NEW ENGLAND which is kinda cool too
This is one the best videos regarding how the engine functions: th-cam.com/video/jLtyNtf9_ew/w-d-xo.html Plus you get to see the small team of brainiacs
I mean it's cool and all, but you could get an engine made out of chocolate go make 3.5 hp. Maybe when it's not a model it might be worth looking into.
*Hub dyno possibly, considering what he is building/researching right now. With this much torque and with R&D in mind he need a very precise machine that doesn't allow the tire to spin/slip
He's about to reach Toyota's Project F1 (Lexus LS400) levels of research and development. Maybe he could even build a reliable, fully billet rotary engine, in-house. Skyactiv-X 2 rotor when? lol
This is a really refreshing 'explanation' video. It is like a magician that does a trick amazingly well...and then agrees to explain how he does the trick, step-by-step, so you fully understand what is happening, yet the next time you see the trick, you enjoy it even MORE. No smoke and mirrors and no BS. Great job!!
I’ve never been interested in rotaries until I watched this channel. It was new territory for me, it was weird and foreign. Watching this channel has made me believe that building a rotary is like the next level in engine building like sure you can build an LS, but can you build a rotary? I hope more people will accept the challenge Rob has silently put down. I certainly will.
That's just the thing, Rotary is actually easier, fewer moving parts, overall very straightforward. The problem is, you can find 1000 guys who know exactly how to make big LS power for every 1 dude who knows how to make big rotary power. Rob is that one dude, and he's preaching the good news of the Dorito to all of us.
@@jttech44 Another problem is rotary engines are really only found in 2 different cars made by the same manufacturer. And they are getting hard to find
So I’ve never built one of these myself but I come from an engineering background. You have a very interesting point about how the engine is held together only using long screws and dowels, i think that the screws are the size they are because they didn’t want to compromise the structural geometric load dissipation of the end plates where it’s screwed in, larger holes exponentially come onwards or outwards. I think you bring up an interesting point about the screws and why the rest of them are thinner than the main holes, do you think that has anything to do with the way such a unique engine “block” expands based on heat? I hypothesize that those stock rods were carefully calculated to expand a certain amount when the engine is warmed up as to not become loose but not stay on too tight so the seals can function better while also keeping a safe retention between the engine “plates” during cold starts. Inserting straight dowels machined into the holes make some sense into making it more stiff but I’d argue that if it has a direct fit to the actual walls on the holes, then the heat transfer and the rate at which it warms up and the heat dispersion would be not worse per day but poor design, it would most likely stress the frame of the engine block in uneven ways and by completely trying to get rid of the torsion flex, it would beneficially save the apex seals and rotors during run time but making it too stiff will inevitably destroy the main shaft. This was actually the problem with the original mazdaspeed lemans 7 series race car, they made everything fixed with super proprietary seals and basically made a special mounting system for the engine plates and also made a custom engine block to hold itsself together. This led to more consistent performance and insane power numbers in a a variable NA engine of all things. Tho only thing that would fail consistently would be the central shaft, this is because like you said, at high rpm and insane power, the rotors will inevitably vibrate, if even a single rotors timing is off or has an ignition cycle that even 1/6000th of a cycle off, (between 4 rotors) it would repeatedly torsionally stress and vibrate the shaft. The engine they used for the VNA 4R 7series engines are super custom made and designed specifically to hold ideal power at around 350 or less hp, ( the kinda avg power number held during the entire 24 hour race) and even then, the central shafts failed. I love what you do but I think it’s simply impossible to try to hold together a 1200hp turbo 4rotor engine, especially when the original design was meant for avg power output of about 110hp and a peak of 280~hp at 2-3 rotors. I think that your engine will specifically suffer more of these problems because you rip around and sometimes race and just rev the shit out of it. Anyway, I think the ideal solution for that would be to use “dowels” and screws or whatever you use that match the diameter of the holes but keep the original thread diameter. I’m sure this is already what you do but the next step would be to specifically modify the exterior of the engine block plates, if you use the edges or extra mold pieces and weld a custom machined tab of some sort to increase the torsion stiffness from the exterior, hell, to make it really strong, you could Mount these exterior supports with an offset against each other so that it really locks. Well that’s all I have to say. You get a lot of comments so you might not see this but I would like your input on that.
not everything is done with full thought or consideration like that, its also not a blackbird, that kind of thermal expansion is simply not feasible on this engine, the area of combustion is very small compared to the thermal mass and cooling capacity of the block. i think they just f*cked up to be honest, its a relatively new type of engine, and not much has been done to research and develop it in comparison to a piston engine. Making the engine a more solid unit not only saves on wear, but conserves more power as more is put into the rotor and not into twisting the engine. After that just comes reliability, i think its possible to simply not have seals on an engine like this, i'd just have a durable but malleable material (so it doesnt chip or crack) as a solid insert, with no springs, and make it take up a larger volume on the apex for strength. i think moving seals are a fallacy and are just hold overs from piston engines. same with lubrication, it can just be lubricated through the fuel. all this is to say the engine isnt perfect, and probably wasnt designed with certain factors in mind.
I was thinking drill through the end plates and do a solid dowel threaded on both ends so everything is clamped down with nuts and have the notched bits like the top of a jack-o'-lantern or a Lovejoy connection like you said. But the most I know about wankels are their basic operations that Mazda used them in cars and that their most common application today is kamikaze drones.
Thanks for the very detailed " long term " research like information ( degradation in general ). Learning this and adding new concepts for secondary thermal engines , I.e. using a rotor as a part of a steam machine and using the wasted heat near the exhaust to generate steam, may also increase efficiency a large step. Duration and overall efficiency can be improved a lot.
Real talk Rob , in my years I have learned the guy who is constantly bragging about how good their shit is , and won't share any secrets. Usually means they don't have a fucking clue and are too fat headed to admit it. Seeing you do this shit and prove yourself makes the world of difference. We learn from our mistakes, you take it to the next level. Keep being awesome and helping us make that reliable horsepower! Well reliable for a rotary .... Be safe Rob !
This is the way it once was, racers helping each other. Competition was left for the track. Started thinking of my Toyota. Loved My Rx3 station wagon until about 110mph. That's where it decided you needed to contact the ATC for take off clearance. Unfortunately for the rotary, 20,000 miles then was about the limit for the apex seals.
So I’ve been doing a lot of thinking later about those tension bolts. What about a brass bushing kit? Use an ARP stud with a press fit brass bushing around it……. It’ll help keep the torsion down using a stronger and thicker bolt, and it’s a softer metal so it allows a little wiggle room for clearance issues. Plus it also doubles as an additional alignment dowl
I love the idea of testing all the different seals to the nth degree just to know and cut through community ambiguity. The custom keyboard community had a guy who would test all sorts of parts and build methods people swore by empirically and called it "keeb science". Love this stuff man, keep it up.
Hi Rob thank you so much for this in depth well thought out run down on Mazda's Rotary. I was fortunate enough to work in the USA (Albuquerque) in 1978 and being an ignorant Aussie thought I would buy a small compact fuel efficient car. And ended up with a Mazda RX4 Gorgeous car. (Didn't even realize there was such a thing as a "Rotary engine" Performance wise it was off the scale. The wife loved it too (Lead foot) Many happy memories.
I use to use Klotz Super Techniplate in all of my 2 stoke lawn equipment, line trimmers, blowers, chainsaws, mainly because I like the castor smell... until my line trimmer got hot and seized up one day after using Klotz for about 2 seasons. When I finally got the piston out of the cylinder, I was expecting to find them all galled up, but it was in fact a buildup of castor residue on the piston skirts that caused the seizure, the cylinder was perfect. The rings were literally glued into the lands so bad, I could not get the rings off the piston without breaking them. I finally got all the residue off the piston, replaced the rings, and used it for many more years... The Klotz made good brush pile fire starter fluid after that, lol! Awesome video Rob.
people like you need to spread more info of these engines like you, we are not far from end of life of the combustion engine and electric is taking over. We all need to try to keep these engines alive and others as long as we can.
Hi Rob, I am installing an RX8 engine into a homebuilt aircraft and the sump metering oil system has been modified by installing an oil metering pump adaptor from rotary aviation. This unit cuts off the sump oil and takes from a two stroke oil container to do the same job still via the metering system. I have also changed out the plastic lines to braided stainless steel and high flow aluminium fittings.
Recently got an rx-8 and just so stoked to have a rotary to work on and fix up. Love this channel and inspires me to work hard to learn the ins and outs of these engines.
Tesla aren’t pushing many boundaries other than going fast. When they can do my annual holiday runs into the Bush and back where chargers aren’t found. I’ll be impressed.
@Julian Florez EXACTLY. Seems like people forgot that before the car company, there was an actual guy that was always pushing the boundaries of everything we know about electricity and frequency. Without him, we might not have A/C power.
While I could probably improve the entire engine with a week or so of solid sit-down thinking, the apex seal is the biggest hurdle to clear as its, as implied, the primary seal in combustion but also the highest concentration of friction per surface area. This would not be an easy job--but it is doable, as it's done in aerospace all the time--but to solve both the oiling and apex seal wear area, I would run the oil line down the center of the E shaft and through channels of the rotor to deposit a misty spray of oil directly beneath the apex seal and then let it wick out to the chamber walls, using the apex as a wipe (a ptfe/teflon/ceramic coating here would also be beneficial but it would be a wear over time investigation to see what kind of mileage you get out of it). The apex seals themselves, one would think, you want a strong alloy that is centered around wear-resistance but also lubricates easily. The cheaper, old school way would be to use tool steel (D2, W1, etc) though the ultra-modern knife steels could be interesting to play with as well. In the event you ever want to take the apex seal into the 21st century with the oiling idea, look into how turbine blades are made for jet engines and their air cooling channels. It's worth the introspective look even from a machining-to-solution investigative learning side, too.
I've followed you since the beginning. I don't know why, but I was always a fan. You seem like a completely different person now. You went balls deep to learn shit and now you look like everyone I know that studied engineering. I love it.
Well, this was a surprise to see in my recommendations out of the blue. I haven't actively watched a car-related video in over a year, and then TH-cam just says 'hey, you know that one neat but kind of obscure category of engine? have an entire video on it'. On that note, fantastic video- very well-explained, very little in the way of wasted time, and I learned a number of things about rotary engines in the process. I was already relatively familiar with them, but they haven't exactly been my main domain when it comes to cars, mostly down to the fact that they're not super common.
Just random quick comment, but as someone who has worked at Valvoline, I have seen that most rotaries actually call for the basic convention oil rather than the synthetic big boy stuff because of the burning and mixing that occurs. That was pretty interesting when i first learned it.
Just a warning, When I used an XRF scanner in my materials course in college, we would zap the same spot on a sample to break through surface coatings and oxides to get down to the raw metal
I think we need a spreadsheet that shows the composition and density of apex seals compared to stock ones if you could do that for us it would be amazing
Dear Sir, I'm a master technician for Mercedes Benz and and hold also master technician status ASE from years ago. I spent 45 years working professionally and I have approximately 100,000 hours of actually mechanical experience. Let me say first that I enjoyed your enthusiasm in your video. That you are a rare commodity for your generation to engage in mechanical pursuits. It's refreshing that anyone would even care about something that more and more is becoming disposable, the internet combustion engine. However I did get a big chuckle when you made a comment about "all of your experience". Respectfully, it's sort of a rule that it takes 10,000 hours to become an expert at just about anything. I don't want this to come across as mean or degrading by any means. The way you come across during your explanations you present as very qualified in your subject at hand. What I enjoyed the most is the sound advice for fixing common problems related to rotary engines since day one. The solutions are elegant and modest to implement with our investing huge amounts of money. Very good ideas indeed. I turn 65 this March and started smoking marijuana at age 13. 53 years give or take a few years off from time to time. However for appearance sake and to seem more credible don't mention that the propane torch has been mislaid due to pot smoking activity. We all know it's legal and a shit load of fun but mixing intoxication of any sort and machinery shows poor judgement. I really don't think that's what you intend.and it just doesn't play well when heard in this context. Otherwise I really like what you have to say and the presentation is on par with professionals with considerably more experience. Good job man! Now a little humor. A guy gets a job at a repair shop and finds out that he has to pass a drug screening. So he's sent home with a bottle to return with a sample. He turns it in and is told that it's the last condition he has to pass as a new hire. The company calls him back a few days later to give him the results. The man on the phone says there are some irregular results. Becoming concerned the fellow applying for the job ask what could be the problem. So the caller explains, your wife has chlamydia your teenage daughter is pregnant and your dog seems to have kidney problems. Otherwise you should get the job if you can turn in a clean urine sample. I have lots of friends in automotive and racing. One friend decades ago racing an RX7 modified to the hilt set a track record a track in the north Bay Area. At the time they had a practice engine and a race engine. The intake port's we're greatly enlarged but they still used the stock intake gasket. They just took a hobby knife at cut the gasket to the larger ports size. After setting a record at the track they went home proud of their accomplishments. Sometime later they took out the race engine to freshen it up for the next race only to find that in the excitement and limited time to change the engine my buddy had forgotten to resize the gasket to the enlarged ports on the intake. The gasket hung above his work bench for years after as a reminder. Oops! This is the sort of thing that pot user's get blamed for. The overall results were positive but the shame is still the same. When I started working on car's there wasn't a computer in sight. Today's cars are rolling computers. In the 35+ years I worked with Mercedes Benz I was always rated in the top 200 technicians out of the 3000-3500 people in the USA working as technicians/mechanics. Best wishes to you in your endeavors. I think you're doing a great job. I hope you inspire more people in your generation to enter the automotive field. I had a tremendous amount of fun and made a good living in an ever changing field.
I’m so proud that you share your experience passion and techniques for repairing rotary engines. Most mechanic’s want even tackle these engines. I have a RX-8, 2005. I love this car it has low mileage and had decreased power after wiring was repaired after rats made a nest in motor and chewed on the wires. The problem on being diagnosed stated in wiring but not wanting to or willing to fix said vehicle. States it is in the wiring, which at one time was repaired locally then shortly after getting it out of shop it wasn’t running normally it didnt have the power especially going up hills. I parked it due to not wanting to blow up the engine. No one wants to take engine apart or look at wiring to see if it can be repaired. This car is sitting outside ruining from sitting up for so long. I’d love to find someone to bring it back to life. This car has a lot of sentimental value to it also. You make these engines sound so simple to fix. It’s refreshing to know that you know your rotary engines. Thank you for sharing your experiences. I wish it would rub off on other mechanic’s. ❤my Mazda.
Ohhhhh yes, I shall take these notes when putting a 2 rotor in my Fiat 850. Especially the oil feed and chamfered rotors. Hell maybe when I get around to it you'll be selling your own rotary engine crate swaps hahaha Amazing work Rob, keep feeding us this crucial information
If you're building a naturally aspirated 2 rotor the 1 piece solid dowels and external oil feed is unecessary. You can buy a solid and hollow 1 piece dowel kit instead although you shouldn't need to for an N/A build, if anything just add a couple dowels. Race clearanced rotors are ideal but only if you intend to rev it to the moon. If you are going turbo then yes, get both upper/lower solid 1 piece dowels and external oil mod, do clearance the rotors then have full rotating assembly balanced, get your plates and housings cnc'd to accept large studs clearanced as dowels. None of this is new information nor secret, well atleast not in this part of the world where he got his clearanced rotors and original 4 rotor from. You can already buy engines built like what Rob explains, how do you think he knows?
16:35 that could so easily be fixed by mazda by simply including locating teeth on the outside edge of the plates so when the tension bolts pull everything together the teeth mesh with each other to eliminate that torque. Or heck with a bit of machining and some strong rings with teeth you could machine teeth into the outside edge of the plates that will mesh with the toothed rings almost like another gasket but instead of sealing its to stop the plates from trying to twist.
i think the problem with that is mazda used cast iron for the rotor housing. the teeth would eventually crack over a certain amount of time and/or HP. could be solved however if they use machined forged metals. in which case i think that would make the engine more expensive to build and sell, and thats a big no no for a commercial engine. but thats an interesting idea still!
Great and practical advice. I feel like buying back my RX8 and ripping the engine out and fixing it. The stepped full length down pin idea is brilliant - typical Kiwi ingenuity. Thanks.
Wonder if that one spot cracks because the coolant runs through, that there's enough difference in thermal expansion between the metal closer to the combustion chamber, and metal further from it. One side is trying to contract, while the other expands? Also considering how many issues from rotaries stem from the uneven thermal expansion, I really wonder if making the engine block out of invar (FeNi36) would help address a number of its issues?
@@F3Ibane may I suggest just make the apex seals out of invar and not the whole engine? There may be some tricks required to make it fit with the coefficient of expansion differentials, granted.
Rotaries are super reliable so long as you can pull the motor every time you have one of these extremely common problems. Seriously though, love rotaries and love you Rob, keep the videos coming.
Rotary reliability has nothing to do with pulling the engine and rebuilding it often. As with any high-stress application, problems are only "extremely common" if you: A. Cut corners on your build. B. Try to ask for more than what your equipment was built to deliver. C. Ignore proper maintenance. The only reason you hear about problems with these engines is because most people have no idea what they are doing with them.
@@rotorhead5826 Well that, and alot of folks running rotaries seriously nowadays are pushing them pretty hard. Speed costs money, how fast do you wanna go?
@@rotorhead5826 seriously, people blow "reliable" engines all the time and acknowledge it was because they over boosted , under cooled them . Peoplr need to understand that 500 hp boosted rotary needs mods to be reliable
not sure if i will ever buy a rotary but watching your channel certainly makes me want to learn more about them, just like you said. i have not seen a clear video with all the rotaryproblems and fixes for them for, so this is an amazing video!!
Rob, are you familiar with the liquid piston engine variation of the rotary engine? Do you think reversing the shapes of the rotor and the chamber is a good idea? It seems to me that putting the apex seals on the wall of the chamber makes sense.
no its NOT a good idea . cause in the ( so called liquid piston engine) the crankshaft is also your air intake. and that crankshaft needs to be big enough to both handle the torque/hp that your engine produces as well as allows all the air to enter your engine. you will have a seriously underpowered engine or an engine that constantly twists or breaks its crankshaft
@@cordellej You make a good point. However, the intended usage might be different. They have a really small 4hp motor, great for "small engine" applications.
Rob, I am unsure if you will ever see this. I am an independent, unschooled, "unprofessional" grassroots engineer. I am working on a new concept for an engine design that shares a lot of similarities, and therefore also base materials, with the Mazda Rotary engine. These videos are instrumental, and if anything inspirational, in my research. Once I'm able to fund my research, I wish to use your guidance to understand more about heat, pressure, stress, and rotary knowledge in general. I can't wait to see the Pikes Peak video to see the culmination of all of your hard work and dedication. Keep up the good work at Dahm Racing Industries! ✌️
I kinda feel like some of these shops stumble upon big hp numbers and thus think oh you need these mods where Rob is being more methodical which I'm here for.
It's usually a case of "well he's running this much power and he said I have to do this" and say one person goes around to 10 different people and they all throw their 2 cents in that's how you end up with a list of unnecessary and pointless work. Some of the crap I have heard over the years being in the engine reconditioning industry is just comical and majority of it usually starts with "my mate at the bar said I need to"
The rotary engine runs so smooth it’s amazing. I could tell just by the sound how fast I was going and it never got stuck in the snow because it delivered the power to the wheels so smoothly.
I mean, all of this makes so much sense. Love the content rob. Stock stuff, just some overlooked areas from mazda, and you have yourself a pretty sturdy engine.
I've always wanted to go rotary. But the closer I get to doing it, stories, rumours, horror stories, myths get in the way. I do most of my own wrenching and the more I see of rotaries, even with their problems, they seem to be so simple to work on and maintain. Even pulling the engine every few 10s of thousands of miles for seal replacement and inspection could be a simple routine. Burning 2 stroke oil is so simple and brilliant. Thanks for the video. I need to do a bit more homework that will include more of your videos. But a cheap RX8 project might be in my future.
Seeing this makes me want to get another rotary in all honesty. My first rotary was a 2004 Mazda RX8 and I love that car, been wanting one of those or even an FB or FC, FD if I find the right one!
this makes me super hopeful that if I do succeed in life as planned... My Veilside RX-7 will survive. It's my dream and I wanna at least get it around 500hp. Maybe a lil less. I don't need 3 or 4 rotors... the sound and look is what I'm getting it for. I wish I coulda met you back in the day when you lived near me. My friend met you which is so small world. I been watching since 2013 ❤️
Rob: These are mistakes we have made and lessons we have learnt through experience. Also Rob: Don't drink the forbidden Coolant milkshake. It doesn't taste good. ...Rob, how you know that?
@@Matty.Hill_87 Work long enough on cars and something will get in your mouth that you don't intend. Used oil is nasty and bitter. Used coolant actually varies a lot in flavor. When it's not sickenly sweet, you're lucky. Regardless, I spit it out and clean my mouth a bit. Who needs that in them?
Great great video. Rebuilding my first rotary, doing a ton of research, taking my time and going to see what happens. Basically bought the car for the sole purpose of learning how to build these engines, not gonna lie so far it's been fun we'll see how things come out lol
I have a completely stock (engine) 2004 RX8 with Mazda installed rebuilt. I have been using Idimitsu in the fuel since day one. It has AEM intake and Borla exhaust with a factory catalytic converter (California). The original engine went 130K (with Idimitsu mixed) and factory specified engine oil (non-synthetic). Internal coolant seal failed on the original engine (white smoke at startup and then eventual flooding from coolant). I used "K-Seal" on the original engine at failure after de-flooding (coolant) and new plugs. I drove it event free in California (with weather temps over 100 many times) for another 12K miles with no issues. My son took over the car to go to College and that is the only reason I had the engine replaced for fear the K-Seal fix could fail. I drove it to Mazda and the mechanic that did the compression test asked why I wanted a new motor as all was good. Anyway, that engine was run only on Shell Premium with the Idimitsu and that is the same for the "new" (Mazda Rebuilt) engine. It has about 60K on it. What should I (my son) be doing to prolong the life of the engine that is in the car? Why does the internal coolant seal fail and what can we do to ensure the Rebuilt does not suffer the same failure? Thank you!
Excellent Video Rob! It's funny to me that you, as a private tuner, have identified and fixed problems in this motor that Mazda, with $Millions of investment in this engine, hasn't figured out. You are an amazing tuner and I sincerely thank you for your hard work and for sharing your discoveries. I hope to see you out racing some day.
"with $Millions of investment in this engine, hasn't figured out" Its less that they "havent figured it out", and more that the solutions arent all genuinely viable for a mass market producer that has to abide by global emissions standards.
The thing about the apex seals is interesting to me because you mention "stock internals" if the rest is in order. I know Mazda 2-piece seals were the first thing to be booted and upgraded back in the 90s when they figured out they crack pretty bad when they do but I wonder how much better 3 piece ones are...just more insurance as you said I'm presuming. Very interesting vid as always Rob. You couldn't not cut it that tiny bit short in the end lmao
There are upsides and downsides to both 2 and 3 piece seals.. 3 piece seal better at low rpm and 2 piece better at high rpm.. the best seals for N.A rotary's are Lannetti ceramic apex seals which are guaranteed for life, lightweight and are reusable, but very expensive.. although don't take well to detonation.. hence why carbon steel are better for turbo rotary's. Racing beat also make great seals.
Great information Rob. It really blows my mind that people are so secretive about their rotaries. If more people were like you and shared the good, really helpful stuff. Then rotary engines probably wouldn't have such a bad reputation. Sadly there is a lot of misinformation out there. Everything you mentioned makes perfect sense to me. Thanks
I enjoyed this video so much, and it all made so much sense, and so simple to understand. Now I think I'm in love with rotary engines again. I've always thought mass continuing in a circle was way better then reciprocating mass. I've raced 2 stroke dirt bikes growing up (bean oil smells so good) and 2 stroke oil had gotten so good that we were running 100 to 1 mix ratio on synthetic. We just never ran lean on fuel - air ratio. Less oil in the fuel keeps octane higher, and a cleaner combustion chamber. Great video, thanks!
Seems to me I heard about that too, a long time ago. I wonder if they "hushed it up" because of fear of alluding to 2-stroke engines. Or maybe they just added the oiling ports on the housing.
Learning by testing, trying to correct problems and making mistakes, them sharing with everyone. You are a good man Rob.
He knows the engine i dont TAHHH DAHH
It’s called passion. This is what you get when money doesn’t rule your life.
Would love to see a video on making the RX8 reliable for those ready to buy one.
Mazda should bring in Mad Mike to point to the weaknesses and be required to make the improvements
@@MrKennyanders idk who mad mike is but if they know the weaknesses just as Robs experiments maybe you can't hold mazda accountable 100% but I would hold them a certain percentage accountable if they don't make the changes neeeded. they can come and quote you millions for R&D costs well it's already R&D'd just Do it and test it hence saving millions and gaining millions in sales if it works in favor. lol.
Just a Random rant over here.
Idk if I'll own a rotary engine, but I'm sure as hell gonna sit here and learn. 21 minute video!!
That's exactly how I feel. Also robs passion and antics are great
yup
Look into pac performance in Australia
@@bloodyricho1 PAC make amazing cars, shame they didn't get back to Rob
Yup. I know for a fact I will never own a rotary. I don't really even care about them, I am a chevy guy through and through. Yet, here I am, and here I shall remain.
It’s an utter shame how the engineering world gave up on the Rotary engine so quickly. Had they gotten the same attention piston engines got, who knows where they’d be today. People like you are putting in the effort to bring it back!
Draw a picture of the combustion chamber seals. Then draw the piston and rings . One is complex, the other is so simple a child could do it.
Most people dont like having to replace their engine every 30k miles, no matter how small it is, not matter how much it is their fault.
@@alexzanderroberts995 how expensive it is to do it though?
@@sonyx5332 depends, do it yourself?
About 200$ worth of equipment
20$ worth of parts
And 1500$ worth of inexperienced balls
To get someone else to do it?
Anywhere from 200-2000
@@alexzanderroberts995 I raced rotary engine for years and held all motor world record. The downfall of the rotary is emissions and fuel economy. Great reliable light weight engines that make tons of power but they are not fuel efficient and can't meet the strict emission laws that all the tree huggers make these days.
THIS! Sad part is, so many in the rotary community will deny and call you a liar because they don't want their customers to be wise and save money. Keep it up! So glad I'm learning this before I do my inevitable rebuild
They can't, cuz they are not the ones that made 1500HP to all 4 wheels and chained their tube chassis 4rotor rx7 to containers at the hoonigan burn yard and did a sick ass burnout. Rob knew first he had to prove the reliability aspect of his engine's. Now that he did, he can talk shit about the bullshitters.
@@Toxic88088 Looks like, because he's willing to risk breaking it, Rob's learning more about where and why it breaks. Watching the quad rotor dance on the end of that chain, and seeing the loads it was generating, was fantastic.
I love the fact that Dahm is shitting on years upon years of shite mechanics (which are responsible for many cool cars having bad reputations in US, not just an engine, because of their incompetence) but also the "boutique" gate keepers. Rotaries are here to stay. Every day there's new rotary content and more and more people who learn that the bullshit is just that, bullshit.
Its a weird balance because ive learned alot from alot of shitty mechanics. But half truths and poor customer service capped their abilities. I have the opportunity to do more R&D than most enthusiasts and i LOVE cutting through the smoke and mirrors. If i can make 1000hp on a clapped to all fuck out 3 rotor then it cant be that secretive. Setting my sights on HP density next. 1000 hp 2 rotor. Then apply that to the 4 rotor and push the envelop
@@RobDahm shitty mechanics show us where corners can be cut.
If my mechanics car doesn’t stink of who knows what, and doesn’t have random switches in it to keep its rusty junk ass going I probably can’t afford them to begin with. But I won’t want to take my car to them because when I ask for dodgy work they won’t touch it.
@@RobDahm From one RX-7 enthusiast to another, thank you!
@@RobDahm my man
@@RobDahm 1000hp is setting the bar high there Rob… when we guna see that? 😁😁😁
We used to remove 3 thou off each side entirely not just the tips. We also machined the actual faces down on the rotors as well. You’d be surprised how different each casting is and how unevenly material removal was on those faces. Ran 13b’s with 58psi making 980+whp pretty much indefinitely for multiple drag seasons on customer cars. Just clearance and balance and run a good studded block and they’ll run forever. There’s no real secrets to be had or magic port work that hasn’t already been tried over the past 50yrs.
When I discuss Rotary engines vs Piston engines with folks I always point out the difference in engineering efforts. The overall effort (engineering/testing/etc) to improve the piston engine absolutely dwarfs the Rotary engine. I often wonder what may have been if the Rotary had even 1/10th of the same effort applied to it. Great video.
I often wonder the same thing. There are definitely issues with rotary engines, but I doubt that any of those are fundamental flaws with the concept. Just look at what we can do now as opposed to 50 years ago. Probably ten times as power dense (more power in 3 small cylinders vs 8 big ones), while also being a hundred times cleaner. If those problem solving skills could have been partly applied to rotaries? I think some really cool technology could have come out of it. Sadly, with the future moving away from combustion, its unlikely that it will ever get that kind of attention.
Jack shit. Fuel economy and torque suck balls.
@@aggonzalezdc They are fundamental flaws though. The power density isn't even that great. If you measure a 4 stroke engine like a rotary the displace is half or you can double the size of the rotary. That's because a rotary fires it's full displace for every rev of the crank while a 4 stroke only fires half it's displacement. So the 1.3L is really a 2.6L and I will assure you a 13b is no match for say a RB26 with similar type builds.
@Mike Woodfill No they don't even the skyactiv rotary put up disappointing numbers, new iterations will too.
Plus the clock has run out for them, the sun is setting on all ICE engines.
My same point when it comes to ICE vs electric cars
Love the fact you’ve gone from starting with a basic knowledge of rotaries, to fully fabricating parts and successfully building and tuning them to 1000+hp.
Dahm, take a fucking bow my friend.
Daddy Dahms Daily Dose of Dorito Dexterity
Agreed really been an awesome journey, thank you
@@dancearoundtheworld5360 Throw some D's on it
The first new car my family had was a 1972 Mazda RX2. I remember how smooth that engine was and it never left my mind. Sadly, the car was totaled when it was three weeks old and we replaced it with a larger car. I thought that the rotary engine would be the thing of the future at the time. Here we are fifty years later and this video is a blast from the past for me. Well done, sir. You have earned another subscriber.
Had 3 Mazda Cosmo coupes back in the day. Fun at high rpm.
TLDW: treat your engine like a 2 stroke, E-85 with 2 stroke oil, replace the dowel rods with solid rods, get thicker tension bolts,
run the oil through the blocks separately instead of through the single oil hole where the dowel is causing block cracks.
Why 2 stroke oil? Fuel lubricity improvement? How about adding biodiesel instead to improve lubricity? Surpassed every other supplement in a recent HFRR fuel lubricity test.
@@wallacegrommet9343 not for lubrication, for oil burning purposes, rotary burns oil and so do 2-stroke engines.
@@patrick2mail You’ve got to be denser than osmium. You add oil to fuel in a 2-stroke engine because it doesn’t get oil to the rings. You run oil premix in a rotary because you’ve deleted the oil injection system and still need to lubricate the apex seals.
thanks dweeb
@@Cjbarker2 yea but why did you delete the oil injection system boss
Dahm just wants the rotary to live. Dahm does not care about secrets.
This is the way.
This is the way.
This is the way.
This is the way
This is the way
This is the way.
Man, I feel like you glossed over detonation, which is a bug issue for the FD. Detonation will destroy those apex seals and, like mentioned, will destroy the rotor housing and the turbochargers on the way out. Two necessary solutions here that weren't mentioned.
First, the stock intercooler for the FD3S is laughably small. A larger intercooler will keep charge air temperature down to reduce the risk of detonation.
Also, the factory apex seals come in two pieces. They do slide around and make somewhat of a better seal but machining the rotors to accept a larger 3mm single piece apex seal is a much better option.
Good bit of misdirection in this video. Most all rotaries die from detonation or overheating.
Cracks in the housing or dowel are rare unless you are pushing high power on S4 housings.
I was also surprised to hear carbon buildup attribute to… coolant? That’s not at all right, it’s due to running rich as hell.
Wouldn't E-85 almost instantly fix the detonation issues because of the octane increase alone?
detonation just sounds gnarly
@@wompa164can’t carbon build up also be attributed to not driving the engine right? I’ve heard that higher rpm’s and driving it harder and faster is better for this engine like a Porsche
@@bigdbandit64went through my Audis internals, not a single bit of buildup, you are right
The Dahm gods have blessed us with another video
God Dahm it's a good day!
@@The_TIP Dahm right !
Dahm you all
God dham it you guys are ROBbing me of my puns
I had to sacrifice a piston engine. I hope you're happy
This has to be one of the most straight up legit gear head engine mod videos I've ever seen. This guy uses science to explain why he does each mod on the engine and not make it sound like hookum. Well done young man!!!
lmao Dahm knows not much to be honest. He's been into rotangs and only just figuring this stuff out now? I don't even own one and knew most of this. If you want actual knowledge look up High performance Academy. There is a reason people are usually popular on youtube: they cater to the lowest common denominator.
@@N4CR homie all you had to tell us is "I don't own one". Maybe you know this stuff in theory but have done nothing to figure it out or help us learn. The lowest common denominator is you
@@N4CR r/iamverybadass
@@savant1592 LMAOOOOO
Really interesting vid, I've said this for a long time, tighter fitting components make much stronger motors. As long as clearances arnt silly tight like f1 motors and you warm things ups properly (2 stroke talk there) then your going to avoid so much hassle in the future. High hp builds are difficult, my daily vehicles are usually low tune massive reliability. My toys are high tune lower reliably... but in the same breath if you warm things up and dont just beat on them out the gate then higher performance motors can still give very respectable bang for buck. Thanks for being an inspiration for many years Rob, I'm genuinely glad it's worked out for you. I'm a bike guy through and through but your passion for rotary engines is genuinely inspiring!
"silly tight like f1 motors"
I feel so sorry for anyone who has to service an AMG1.
Thanks Rob! Sad to say, you probably already have a target on your back. I can't wait to learn about the different compositions of the apex seals. I'm sure most of them are hot-work alloys. I've seen a 160k mile mazda seal under a metallurgical microscope. It's amazing what they did!
What were you able to see? I really would like to know. Cheers from a fellow Rotor Head.
Man I just love that you’re just putting all your results and solutions out like this and I bet lots of rotary guys that watched this are making plans to sort out their motors now
This guy is a REAL one!!!
In an ocean of confusion and needless upgrades... it's refreshing to get realworld practical guidance with an accompanying explanation of the "WHY" supporting the recommendations!!!
A Genius IMHO!!!
Thank You for the great videos!!!👍💯🙏
Guys in the shop in one of robs car: why we goin do fuckin fast!?
Rob sitting there, stationary: I knew I shouldn't have given them the torch
we all had our suspicions, but the confirmation is nice lmao.
i mean, it is cali afterall
As a tech this is hands down my favorite type of auto content. Diving into the mechanics. Analyzing what can and will go wrong. And then coming up with solutions, that may or may not work. And be able to learn from it and convey that knowledge to others.
I plan on fixing my 2004 Rx 8. She has been sitting for a little bit. I start her up once in a while. Everyone keeps on telling me to swap that boat anchor out and I refuse. ( yes I'm a girl that knows a lot more about rotary then the guys around me ) I've done most of the work on my car. I love 💕 working on cars. Can't wait to pull my engine and see inside and at the same time nervous. It takes a lot of money to rebuild. Good thing im about to start a job. Great Vid by the way. I'm going to prove them all wrong one of these days a rotary can be reliable. Hopefully sooner then later 13B
Good luck with it m8
This is why i watch you Rob over most youtube creators. Informative and clearing up the BS, no one deserves to be ripped off with pointless modifications and i'm glad you are helping the community and enthusiast!
Tearing apart a rotary engine, AND putting it back together, was one of the most rewarding experiences I've ever had.
The Wankel Engine has SO much potential. It defies belief that only one company was willing to take the risks to produce it. I remember coming to the exact same conclusion you did about the two-stroke oil. E-85...that's brilliant because it's a little bit counter intuitive. I always wondered why the apex seals would fail...which you explained beautifully. I just had a thought about a maranging stainless steel alloy. Such an alloy actually gets stronger as it gets hotter...up to a certain temperature. You may need some babbit metals alloyed with it to provide proper wear characteristics. You need to study metallurgy on your own. A smart guy like you may come up with the best alloy and solve that issue once and for all. Also, the spring under the apex seal, maybe there's some super unobtanium alloy that will last the useful life of the engine. I think you should focus on the aviation market...once you fix all of the issues. It's a good compromise between a reciprocating engine & gas turbine. The sky is the limit!
NSU also produced a Wankel engine. That was a failure too.
Several automakers worked to solve the problems, but only Mazda decided to bring them to market.
If all you care about is compactness and power, then sure there's nothing wrong with Wankels. But if you start needing to follow emissions and efficiency requirements, they start running into the same type of problems that prevent 2-stroke engines from going into mass produced cars. two-stroke oil doesn't burn cleanly, difficulty in implementing valve timing, the fact that the combustion chamber is moving at high speed makes it difficult to burn all the fuel fast enough, limitation in compression ratio.
@@Appletank8 I could be mistaken, but I don’t think the emissions would hold it back in the aviation sector. Of course, leave it to the EPA long enough, and they’ll mandate electric motors for private aircraft.
@@skookapalooza2016 Yes small aircraft generally has less emissions regulations, and is more focused on absolute reliability, though they are finally phasing out leaded fuel for one. Still, a more efficient engine does mean you can fly further on the same tank of gas, so while a well maintained wankel can generally operate pretty reliably, their range would likely be a bit worse.
Wish your channel existed 15 years ago! LOL. I've owned and still am the proud owner of the 7, and on my 6th engine. Went thru tune shops that didn't know what they're doing, and engines that were poorly built. It was funny you mentioned the ripple water mod cuz I had that done to one of my engines, and it blew during tuning 1 week after it was put in the car. I too had serious carbon build up on rotors in one of my engines and a chunk of that came loose which ultimately killed the apex and the engine. Believe it or not, that build was by Amemiya and was only making 500hps. The engine lasted about 4 years and 30,000km. "Too much city driving" was to blame for the carbon buildup, but never thot that was the real reason. What you're doing is super awesome and helping rotary lovers globally while fulfilling our dreams at the same time. Good on you, thank you from my heart, and keep up the phenomenal channel! Can't wait to see your next video on apex seals.
“That’s what you get when you’re surrounded by guys who smoke weed in the shop”
RIP Rob’s torch
Dabs :)
Damn he threw his "buddies or employees" under the bus Haha
They need to quit taking the damn torch lol
@@eddiepFW2345 perhaps even "under the blunt", if you will
@@RobDahm put it on a chain 😆🤣
Awesome video, I’ve been tempted to buy an RX8 several times, but scared off by all the engine problems I’ve heard about. If I could find a local shop that could do all these mods, then I would seriously consider buying a used RX8
I’ve always been scared of rotary engines. Just because everything is always such a secret. I really appreciate you taking the time to educate us
It's not a secret that the Wankel is a poor design.
@@RayleighCriterion Troll alert. Do not engage.
Ok bud
@@ujiltromm7358 He's actually right though. Those Wankel designs have been a lot more susceptible to failure unlike a lot of other engines I have ever seen or heard of due to its low thermal efficiency and unreliability later on.
Regardless how hard Mazda tries to improve or come with their own "solutions", how great it might be on gas, or how much less moving parts there are, if a seal on it breaks and coolant starts leaking inside it, that engine is ready to go no matter how hard you try to save it. But if powerplant is your specialty and you like taking engines apart, more power to you. But for me, I need something that gives me the best to both worlds: fuel saving, and reliable engine that will last much longer than 100k miles before a planned overhaul (or worsecase scenario: engine rebuild).
@@EdnovStormbrewer You're looking for the Toyota 4 cylinder or the Toyota 4 cylinder hybrid.
Most reliable for up to 300K miles with regular oil changes.
Sounds like the ideal rotary engine has two oil systems, the lubrication system and the combustion chamber system.
The dowel tie rod issue I would be reluctant to put a one piece sized steel element through an aluminum block due to thermal expansion geometry. If anything you put a hex-shafted steel fastener through a shrink fit hex-broached aluminum dowel body. That allows your aluminum parts to grow together but retains decent unity between the steel and aluminum parts. Sounds like an expensive machining job though.
Same thoughts, which made me think why not add locating/locking/torsion pins. I would make temporary punch pins to put into one side where initial placement holes would be made, assemble the parts and whack with a rubber mallet or tap with a copper one. Drill out adjacent pin holes and you have a much sturdier engine assembly with pins holding rotationary forces instead of relying on bolts having two jobs.
The only thing I would change is to increase the thread diameter to reduce stress concentration at the thread base and reduce allowable strain in the threaded section. I don't believe the thermal expansion and contraction is anything to be concerned about as these are non interference fit parts and will have clearance to work at operational temperatures. I also do not see any advantage to having a hex shaft section over a round, can you explain your thinking around that please? I would have thought an Al dowel broached hex, pre-stained and subjected to static and dynamic loads would have high levels of stress concentration and prone to cracking, cost not being a consideration in any case
Ι tottaly agree with you about dowel tie rod issues.
Metal doesn't "swell" with heat, it expands. And Al expands more than Fe. So long as the rods fit, cold, they will fit, hot.
Why do the "blocks" have to even be aluminum? Not like a big ole large block iron muscle car motor....fairly small casting compared to those? what if they were NC machined from billet steel or iron?
OR for the aluminum blocks what if the dowels were also made of aluminum like the block but with a machined hole the entire length to accommodate a splined steel rod pressed all the way through it!!?? Idk if splined is the right word but I picture a bunch of sharp ridges all the way around the steel rod the splined running parallel the length of the rod (except where threaded on the ends of course)....the splined diameter would be slightly larger diameter than the inside bore of the aluminum dowels so that when pressed into place it would actually displace material and be totally locked into place with zero slop and yet be able to compensate for your thermal expansion due there actually being expansion space net to each spine? I have seen little dowel pins like that pressed into aluminum just to lock them from spinning but this would be a different goal/application ...just an idea from a non qualified non engineer in case it is dumb for some reason
As a man who does computers and is interested(but relatively young) car guy and hopefully engineer I must say I am impressed. You show stuff what a real tuner shows. You test things, go through trial and error, make notes and document your research. A true engineer and a man of science. You also have a clean way of explaining the reasons and solutions as well as not wasting time or using cheap attention tricks. Must say I'm trully impressed and I'm looking forward to seeing more
I love how you're changing the game for rotary engines. As a mechanic who has always hated how engineers cut corners to reduce costs it's so refreshing to see all the bs cut out and someone with the ability to redesign something the way it should be designed. Keep up the good work, I look forward to these more technical videos
The mistakes made by Mazda are being undone by the dudes at LIQUIDPISTON
They basically just flipped the design of the Mazda rotary engine and made a far superior engine. (They’re a pretty small team of engineers)
They operate here in NEW ENGLAND which is kinda cool too
This is one the best videos regarding how the engine functions: th-cam.com/video/jLtyNtf9_ew/w-d-xo.html
Plus you get to see the small team of brainiacs
I mean it's cool and all, but you could get an engine made out of chocolate go make 3.5 hp. Maybe when it's not a model it might be worth looking into.
It seems to be time for you to have an engine dyno for testing.
Yup! That would be absolutely amazing for rob, and imo especially useful for the rapid prototyping he does. R&D to the next level :D
*Hub dyno possibly, considering what he is building/researching right now. With this much torque and with R&D in mind he need a very precise machine that doesn't allow the tire to spin/slip
He's about to reach Toyota's Project F1 (Lexus LS400) levels of research and development. Maybe he could even build a reliable, fully billet rotary engine, in-house.
Skyactiv-X 2 rotor when? lol
@@powerprime99 they're talking about an actual engine dyno, like engine only. it's worlds more useful for what Rob is doing.
indeed, would be the next big step and upgrade for testing parts in the shop.
This is a really refreshing 'explanation' video. It is like a magician that does a trick amazingly well...and then agrees to explain how he does the trick, step-by-step, so you fully understand what is happening, yet the next time you see the trick, you enjoy it even MORE. No smoke and mirrors and no BS. Great job!!
I’ve never been interested in rotaries until I watched this channel. It was new territory for me, it was weird and foreign. Watching this channel has made me believe that building a rotary is like the next level in engine building like sure you can build an LS, but can you build a rotary? I hope more people will accept the challenge Rob has silently put down. I certainly will.
That's just the thing, Rotary is actually easier, fewer moving parts, overall very straightforward. The problem is, you can find 1000 guys who know exactly how to make big LS power for every 1 dude who knows how to make big rotary power. Rob is that one dude, and he's preaching the good news of the Dorito to all of us.
@@jttech44 Another problem is rotary engines are really only found in 2 different cars made by the same manufacturer. And they are getting hard to find
So I’ve never built one of these myself but I come from an engineering background. You have a very interesting point about how the engine is held together only using long screws and dowels, i think that the screws are the size they are because they didn’t want to compromise the structural geometric load dissipation of the end plates where it’s screwed in, larger holes exponentially come onwards or outwards. I think you bring up an interesting point about the screws and why the rest of them are thinner than the main holes, do you think that has anything to do with the way such a unique engine “block” expands based on heat? I hypothesize that those stock rods were carefully calculated to expand a certain amount when the engine is warmed up as to not become loose but not stay on too tight so the seals can function better while also keeping a safe retention between the engine “plates” during cold starts. Inserting straight dowels machined into the holes make some sense into making it more stiff but I’d argue that if it has a direct fit to the actual walls on the holes, then the heat transfer and the rate at which it warms up and the heat dispersion would be not worse per day but poor design, it would most likely stress the frame of the engine block in uneven ways and by completely trying to get rid of the torsion flex, it would beneficially save the apex seals and rotors during run time but making it too stiff will inevitably destroy the main shaft. This was actually the problem with the original mazdaspeed lemans 7 series race car, they made everything fixed with super proprietary seals and basically made a special mounting system for the engine plates and also made a custom engine block to hold itsself together. This led to more consistent performance and insane power numbers in a a variable NA engine of all things. Tho only thing that would fail consistently would be the central shaft, this is because like you said, at high rpm and insane power, the rotors will inevitably vibrate, if even a single rotors timing is off or has an ignition cycle that even 1/6000th of a cycle off, (between 4 rotors) it would repeatedly torsionally stress and vibrate the shaft. The engine they used for the VNA 4R 7series engines are super custom made and designed specifically to hold ideal power at around 350 or less hp, ( the kinda avg power number held during the entire 24 hour race) and even then, the central shafts failed. I love what you do but I think it’s simply impossible to try to hold together a 1200hp turbo 4rotor engine, especially when the original design was meant for avg power output of about 110hp and a peak of 280~hp at 2-3 rotors. I think that your engine will specifically suffer more of these problems because you rip around and sometimes race and just rev the shit out of it. Anyway, I think the ideal solution for that would be to use “dowels” and screws or whatever you use that match the diameter of the holes but keep the original thread diameter. I’m sure this is already what you do but the next step would be to specifically modify the exterior of the engine block plates, if you use the edges or extra mold pieces and weld a custom machined tab of some sort to increase the torsion stiffness from the exterior, hell, to make it really strong, you could Mount these exterior supports with an offset against each other so that it really locks. Well that’s all I have to say. You get a lot of comments so you might not see this but I would like your input on that.
@一慶 4444 cool story bro.
Racing Beat make all sorts of custom parts to stop the torsional load on these engines
not everything is done with full thought or consideration like that, its also not a blackbird, that kind of thermal expansion is simply not feasible on this engine, the area of combustion is very small compared to the thermal mass and cooling capacity of the block. i think they just f*cked up to be honest, its a relatively new type of engine, and not much has been done to research and develop it in comparison to a piston engine. Making the engine a more solid unit not only saves on wear, but conserves more power as more is put into the rotor and not into twisting the engine. After that just comes reliability, i think its possible to simply not have seals on an engine like this, i'd just have a durable but malleable material (so it doesnt chip or crack) as a solid insert, with no springs, and make it take up a larger volume on the apex for strength. i think moving seals are a fallacy and are just hold overs from piston engines. same with lubrication, it can just be lubricated through the fuel.
all this is to say the engine isnt perfect, and probably wasnt designed with certain factors in mind.
holy shit guy 😯
I was thinking drill through the end plates and do a solid dowel threaded on both ends so everything is clamped down with nuts and have the notched bits like the top of a jack-o'-lantern or a Lovejoy connection like you said. But the most I know about wankels are their basic operations that Mazda used them in cars and that their most common application today is kamikaze drones.
Thanks for the very detailed " long term " research like information ( degradation in general ). Learning this and adding new concepts for secondary thermal engines , I.e. using a rotor as a part of a steam machine and using the wasted heat near the exhaust to generate steam, may also increase efficiency a large step. Duration and overall efficiency can be improved a lot.
Real talk Rob , in my years I have learned the guy who is constantly bragging about how good their shit is , and won't share any secrets. Usually means they don't have a fucking clue and are too fat headed to admit it.
Seeing you do this shit and prove yourself makes the world of difference.
We learn from our mistakes, you take it to the next level. Keep being awesome and helping us make that reliable horsepower!
Well reliable for a rotary ....
Be safe Rob !
This is the way it once was, racers helping each other. Competition was left for the track.
Started thinking of my Toyota. Loved My Rx3 station wagon until about 110mph. That's where it decided you needed to contact the ATC for take off clearance. Unfortunately for the rotary, 20,000 miles then was about the limit for the apex seals.
So I’ve been doing a lot of thinking later about those tension bolts. What about a brass bushing kit? Use an ARP stud with a press fit brass bushing around it……. It’ll help keep the torsion down using a stronger and thicker bolt, and it’s a softer metal so it allows a little wiggle room for clearance issues. Plus it also doubles as an additional alignment dowl
That steak is rare.
**the steak is* *Rob Dahm with* *a conclusive ending**
Yes, that is quite rare.
I'm sorry but it's against resturant policy to serve live animals...
This is like $100K worth of information in one free video
Rob spills some beans
Theres a wealth of even more free knowledge in the Racing Beat technical manual on their website that covers a lot of this.
Great video man, it's really nice that people like you keep the rotary alive and improve it.
I love the idea of testing all the different seals to the nth degree just to know and cut through community ambiguity. The custom keyboard community had a guy who would test all sorts of parts and build methods people swore by empirically and called it "keeb science". Love this stuff man, keep it up.
oh yeah, the keyboard community is straight up horrible. Elitism and bigotry at its finest.
Hi Rob thank you so much for this in depth well thought out run down on Mazda's Rotary. I was fortunate enough to work in the USA (Albuquerque) in 1978 and being an ignorant Aussie thought I would buy a small compact fuel efficient car. And ended up with a Mazda RX4 Gorgeous car. (Didn't even realize there was such a thing as a "Rotary engine" Performance wise it was off the scale. The wife loved it too (Lead foot) Many happy memories.
I use to use Klotz Super Techniplate in all of my 2 stoke lawn equipment, line trimmers, blowers, chainsaws, mainly because I like the castor smell... until my line trimmer got hot and seized up one day after using Klotz for about 2 seasons. When I finally got the piston out of the cylinder, I was expecting to find them all galled up, but it was in fact a buildup of castor residue on the piston skirts that caused the seizure, the cylinder was perfect. The rings were literally glued into the lands so bad, I could not get the rings off the piston without breaking them. I finally got all the residue off the piston, replaced the rings, and used it for many more years... The Klotz made good brush pile fire starter fluid after that, lol! Awesome video Rob.
😂
New Zealand has some amazing rotary shops that have built some amazing cars be so awesome if you did a tour here.
Yeah good luck getting into the country any time soon, especially from the states.
NZ, the Rotary King of countries. Have seen some nice engineering come out of Oz for parts though NZ has had more people use them in an application.
Puerto Rico are good with rotary's aswell.
people like you need to spread more info of these engines like you, we are not far from end of life of the combustion engine and electric is taking over. We all need to try to keep these engines alive and others as long as we can.
Hi Rob, I am installing an RX8 engine into a homebuilt aircraft and the sump metering oil system has been modified by installing an oil metering pump adaptor from rotary aviation. This unit cuts off the sump oil and takes from a two stroke oil container to do the same job still via the metering system. I have also changed out the plastic lines to braided stainless steel and high flow aluminium fittings.
You're doing wonders for the community! The honesty of this channel gives me hope for my own future rebuild.
Thanks for sharing
Wow sobrang busy mo idol me time kapa mag learn hehe idol
Recently got an rx-8 and just so stoked to have a rotary to work on and fix up. Love this channel and inspires me to work hard to learn the ins and outs of these engines.
You're the Tesla of Rotary Engines. It's always fun seeing you push the boundaries of what we've all thought was possible with rotary engines.
Tesla aren’t pushing many boundaries other than going fast. When they can do my annual holiday runs into the Bush and back where chargers aren’t found. I’ll be impressed.
@Julian Florez EXACTLY. Seems like people forgot that before the car company, there was an actual guy that was always pushing the boundaries of everything we know about electricity and frequency. Without him, we might not have A/C power.
While I could probably improve the entire engine with a week or so of solid sit-down thinking, the apex seal is the biggest hurdle to clear as its, as implied, the primary seal in combustion but also the highest concentration of friction per surface area. This would not be an easy job--but it is doable, as it's done in aerospace all the time--but to solve both the oiling and apex seal wear area, I would run the oil line down the center of the E shaft and through channels of the rotor to deposit a misty spray of oil directly beneath the apex seal and then let it wick out to the chamber walls, using the apex as a wipe (a ptfe/teflon/ceramic coating here would also be beneficial but it would be a wear over time investigation to see what kind of mileage you get out of it). The apex seals themselves, one would think, you want a strong alloy that is centered around wear-resistance but also lubricates easily. The cheaper, old school way would be to use tool steel (D2, W1, etc) though the ultra-modern knife steels could be interesting to play with as well.
In the event you ever want to take the apex seal into the 21st century with the oiling idea, look into how turbine blades are made for jet engines and their air cooling channels. It's worth the introspective look even from a machining-to-solution investigative learning side, too.
I've followed you since the beginning. I don't know why, but I was always a fan. You seem like a completely different person now. You went balls deep to learn shit and now you look like everyone I know that studied engineering. I love it.
Well, this was a surprise to see in my recommendations out of the blue. I haven't actively watched a car-related video in over a year, and then TH-cam just says 'hey, you know that one neat but kind of obscure category of engine? have an entire video on it'.
On that note, fantastic video- very well-explained, very little in the way of wasted time, and I learned a number of things about rotary engines in the process. I was already relatively familiar with them, but they haven't exactly been my main domain when it comes to cars, mostly down to the fact that they're not super common.
Just random quick comment, but as someone who has worked at Valvoline, I have seen that most rotaries actually call for the basic convention oil rather than the synthetic big boy stuff because of the burning and mixing that occurs. That was pretty interesting when i first learned it.
Just a warning, When I used an XRF scanner in my materials course in college, we would zap the same spot on a sample to break through surface coatings and oxides to get down to the raw metal
I think we need a spreadsheet that shows the composition and density of apex seals compared to stock ones if you could do that for us it would be amazing
Dear Sir, I'm a master technician for Mercedes Benz and and hold also master technician status ASE from years ago. I spent 45 years working professionally and I have approximately 100,000 hours of actually mechanical experience.
Let me say first that I enjoyed your enthusiasm in your video. That you are a rare commodity for your generation to engage in mechanical pursuits. It's refreshing that anyone would even care about something that more and more is becoming disposable, the internet combustion engine.
However I did get a big chuckle when you made a comment about "all of your experience". Respectfully, it's sort of a rule that it takes 10,000 hours to become an expert at just about anything. I don't want this to come across as mean or degrading by any means. The way you come across during your explanations you present as very qualified in your subject at hand.
What I enjoyed the most is the sound advice for fixing common problems related to rotary engines since day one. The solutions are elegant and modest to implement with our investing huge amounts of money. Very good ideas indeed.
I turn 65 this March and started smoking marijuana at age 13. 53 years give or take a few years off from time to time. However for appearance sake and to seem more credible don't mention that the propane torch has been mislaid due to pot smoking activity. We all know it's legal and a shit load of fun but mixing intoxication of any sort and machinery shows poor judgement. I really don't think that's what you intend.and it just doesn't play well when heard in this context.
Otherwise I really like what you have to say and the presentation is on par with professionals with considerably more experience. Good job man!
Now a little humor. A guy gets a job at a repair shop and finds out that he has to pass a drug screening. So he's sent home with a bottle to return with a sample. He turns it in and is told that it's the last condition he has to pass as a new hire. The company calls him back a few days later to give him the results. The man on the phone says there are some irregular results. Becoming concerned the fellow applying for the job ask what could be the problem. So the caller explains, your wife has chlamydia your teenage daughter is pregnant and your dog seems to have kidney problems. Otherwise you should get the job if you can turn in a clean urine sample.
I have lots of friends in automotive and racing. One friend decades ago racing an RX7 modified to the hilt set a track record a track in the north Bay Area. At the time they had a practice engine and a race engine. The intake port's we're greatly enlarged but they still used the stock intake gasket. They just took a hobby knife at cut the gasket to the larger ports size. After setting a record at the track they went home proud of their accomplishments. Sometime later they took out the race engine to freshen it up for the next race only to find that in the excitement and limited time to change the engine my buddy had forgotten to resize the gasket to the enlarged ports on the intake. The gasket hung above his work bench for years after as a reminder. Oops! This is the sort of thing that pot user's get blamed for. The overall results were positive but the shame is still the same.
When I started working on car's there wasn't a computer in sight. Today's cars are rolling computers. In the 35+ years I worked with Mercedes Benz I was always rated in the top 200 technicians out of the 3000-3500 people in the USA working as technicians/mechanics.
Best wishes to you in your endeavors. I think you're doing a great job. I hope you inspire more people in your generation to enter the automotive field. I had a tremendous amount of fun and made a good living in an ever changing field.
I’m so proud that you share your experience passion and techniques for repairing rotary engines. Most mechanic’s want even tackle these engines. I have a RX-8, 2005. I love this car it has low mileage and had decreased power after wiring was repaired after rats made a nest in motor and chewed on the wires. The problem on being diagnosed stated in wiring but not wanting to or willing to fix said vehicle. States it is in the wiring, which at one time was repaired locally then shortly after getting it out of shop it wasn’t running normally it didnt have the power especially going up hills. I parked it due to not wanting to blow up the engine. No one wants to take engine apart or look at wiring to see if it can be repaired. This car is sitting outside ruining from sitting up for so long. I’d love to find someone to bring it back to life. This car has a lot of sentimental value to it also. You make these engines sound so simple to fix. It’s refreshing to know that you know your rotary engines. Thank you for sharing your experiences. I wish it would rub off on other mechanic’s. ❤my Mazda.
Ohhhhh yes, I shall take these notes when putting a 2 rotor in my Fiat 850. Especially the oil feed and chamfered rotors. Hell maybe when I get around to it you'll be selling your own rotary engine crate swaps hahaha
Amazing work Rob, keep feeding us this crucial information
If you're building a naturally aspirated 2 rotor the 1 piece solid dowels and external oil feed is unecessary. You can buy a solid and hollow 1 piece dowel kit instead although you shouldn't need to for an N/A build, if anything just add a couple dowels. Race clearanced rotors are ideal but only if you intend to rev it to the moon.
If you are going turbo then yes, get both upper/lower solid 1 piece dowels and external oil mod, do clearance the rotors then have full rotating assembly balanced, get your plates and housings cnc'd to accept large studs clearanced as dowels.
None of this is new information nor secret, well atleast not in this part of the world where he got his clearanced rotors and original 4 rotor from.
You can already buy engines built like what Rob explains, how do you think he knows?
16:35 that could so easily be fixed by mazda by simply including locating teeth on the outside edge of the plates so when the tension bolts pull everything together the teeth mesh with each other to eliminate that torque. Or heck with a bit of machining and some strong rings with teeth you could machine teeth into the outside edge of the plates that will mesh with the toothed rings almost like another gasket but instead of sealing its to stop the plates from trying to twist.
i think the problem with that is mazda used cast iron for the rotor housing. the teeth would eventually crack over a certain amount of time and/or HP. could be solved however if they use machined forged metals. in which case i think that would make the engine more expensive to build and sell, and thats a big no no for a commercial engine. but thats an interesting idea still!
Great and practical advice. I feel like buying back my RX8 and ripping the engine out and fixing it. The stepped full length down pin idea is brilliant - typical Kiwi ingenuity. Thanks.
Wonder if that one spot cracks because the coolant runs through, that there's enough difference in thermal expansion between the metal closer to the combustion chamber, and metal further from it. One side is trying to contract, while the other expands?
Also considering how many issues from rotaries stem from the uneven thermal expansion, I really wonder if making the engine block out of invar (FeNi36) would help address a number of its issues?
I don't even want to imagine what a set of invar irons would cost 👀
@@F3Ibane may I suggest just make the apex seals out of invar and not the whole engine? There may be some tricks required to make it fit with the coefficient of expansion differentials, granted.
Rotaries are super reliable so long as you can pull the motor every time you have one of these extremely common problems.
Seriously though, love rotaries and love you Rob, keep the videos coming.
Rotary reliability has nothing to do with pulling the engine and rebuilding it often. As with any high-stress application, problems are only "extremely common" if you:
A. Cut corners on your build.
B. Try to ask for more than what your equipment was built to deliver.
C. Ignore proper maintenance.
The only reason you hear about problems with these engines is because most people have no idea what they are doing with them.
@@rotorhead5826 Well that, and alot of folks running rotaries seriously nowadays are pushing them pretty hard.
Speed costs money, how fast do you wanna go?
@@rotorhead5826 seriously, people blow "reliable" engines all the time and acknowledge it was because they over boosted , under cooled them . Peoplr need to understand that 500 hp boosted rotary needs mods to be reliable
not sure if i will ever buy a rotary but watching your channel certainly makes me want to learn more about them, just like you said. i have not seen a clear video with all the rotaryproblems and fixes for them for, so this is an amazing video!!
Rob, are you familiar with the liquid piston engine variation of the rotary engine? Do you think reversing the shapes of the rotor and the chamber is a good idea? It seems to me that putting the apex seals on the wall of the chamber makes sense.
The big win of the Liquid Piston system is that you get three combustion chambers per rotor, while Wankel engines only have one.
no its NOT a good idea . cause in the ( so called liquid piston engine) the crankshaft is also your air intake. and that crankshaft needs to be big enough to both handle the torque/hp that your engine produces as well as allows all the air to enter your engine. you will have a seriously underpowered engine or an engine that constantly twists or breaks its crankshaft
@@cordellej You make a good point. However, the intended usage might be different. They have a really small 4hp motor, great for "small engine" applications.
@@cordellej The top end potential is probably going to be lower but it should be fine for under 200hp applications
Rob’s drug references are hilarious, makes me feel right at home like hanging out with some old high school buddies lmao
Rob, I am unsure if you will ever see this. I am an independent, unschooled, "unprofessional" grassroots engineer. I am working on a new concept for an engine design that shares a lot of similarities, and therefore also base materials, with the Mazda Rotary engine. These videos are instrumental, and if anything inspirational, in my research. Once I'm able to fund my research, I wish to use your guidance to understand more about heat, pressure, stress, and rotary knowledge in general. I can't wait to see the Pikes Peak video to see the culmination of all of your hard work and dedication. Keep up the good work at Dahm Racing Industries! ✌️
I kinda feel like some of these shops stumble upon big hp numbers and thus think oh you need these mods where Rob is being more methodical which I'm here for.
It's usually a case of "well he's running this much power and he said I have to do this" and say one person goes around to 10 different people and they all throw their 2 cents in that's how you end up with a list of unnecessary and pointless work. Some of the crap I have heard over the years being in the engine reconditioning industry is just comical and majority of it usually starts with "my mate at the bar said I need to"
I never have owned or driven a rotary, I still found this interesting. Thanks Rob.
The rotary engine runs so smooth it’s amazing. I could tell just by the sound how fast I was going and it never got stuck in the snow because it delivered the power to the wheels so smoothly.
The best rotary channel on TH-cam!!
I give you that!!
💖💖💖💖💖
I mean, all of this makes so much sense. Love the content rob. Stock stuff, just some overlooked areas from mazda, and you have yourself a pretty sturdy engine.
-Diablo in a rotary shop- *chuckles* "I'M IN DANGER"
So now he gets fenced off at the Super Trofeo at Laguna Seca
That Diablo is so damn cool
In my opinion it’s the most coolest Lamborghini next to the SVJ
I've always wanted to go rotary. But the closer I get to doing it, stories, rumours, horror stories, myths get in the way.
I do most of my own wrenching and the more I see of rotaries, even with their problems, they seem to be so simple to work on and maintain. Even pulling the engine every few 10s of thousands of miles for seal replacement and inspection could be a simple routine. Burning 2 stroke oil is so simple and brilliant.
Thanks for the video. I need to do a bit more homework that will include more of your videos. But a cheap RX8 project might be in my future.
Seeing this makes me want to get another rotary in all honesty. My first rotary was a 2004 Mazda RX8 and I love that car, been wanting one of those or even an FB or FC, FD if I find the right one!
Dahm, this could have been two hours long and I wouldn't have noticed. Great video, loved geeking out on the tech.
Man the 2stroke idea is brilliant.
"This is a corner seal in METH"
Don't be a corner seal on meth
Reckon, 20/80 percentage, casual watchers thought amphetamines, and the automotive fan base thought Methanol. :)
@@PiDsPagePrototypes I immediately thought methanol and then thought about it for a couple seconds and went "Haha funny joke Mr. Dahm"
I actually was thinking of nitromethane myself
@@mattcroft Top Fuel Rotary??? Hrrrrrm.....
To this day I'm still amazed with how much engineering has gone into this engine for it to work.
this makes me super hopeful that if I do succeed in life as planned...
My Veilside RX-7 will survive.
It's my dream and I wanna at least get it around 500hp. Maybe a lil less.
I don't need 3 or 4 rotors... the sound and look is what I'm getting it for.
I wish I coulda met you back in the day when you lived near me.
My friend met you which is so small world. I been watching since 2013 ❤️
I didn’t knew I was in rotary church and reverend Dahm was speaking!
Rob: These are mistakes we have made and lessons we have learnt through experience.
Also Rob: Don't drink the forbidden Coolant milkshake. It doesn't taste good.
...Rob, how you know that?
I have no doubt that he has at some point tasted the forbidden milkshake 😂
mmmMMMmmm forbidden milkshake
@@Matty.Hill_87 Work long enough on cars and something will get in your mouth that you don't intend. Used oil is nasty and bitter. Used coolant actually varies a lot in flavor. When it's not sickenly sweet, you're lucky.
Regardless, I spit it out and clean my mouth a bit. Who needs that in them?
Great great video. Rebuilding my first rotary, doing a ton of research, taking my time and going to see what happens. Basically bought the car for the sole purpose of learning how to build these engines, not gonna lie so far it's been fun we'll see how things come out lol
Fascinating - thanks for the in-depth look at this marvelous bit of engineering!
Imagine what Rob could do with a team if engineers and his "need to know attitude".
Mazda and the Ford motor company gave it a go.....still junk.
I have a completely stock (engine) 2004 RX8 with Mazda installed rebuilt. I have been using Idimitsu in the fuel since day one. It has AEM intake and Borla exhaust with a factory catalytic converter (California). The original engine went 130K (with Idimitsu mixed) and factory specified engine oil (non-synthetic). Internal coolant seal failed on the original engine (white smoke at startup and then eventual flooding from coolant). I used "K-Seal" on the original engine at failure after de-flooding (coolant) and new plugs. I drove it event free in California (with weather temps over 100 many times) for another 12K miles with no issues. My son took over the car to go to College and that is the only reason I had the engine replaced for fear the K-Seal fix could fail. I drove it to Mazda and the mechanic that did the compression test asked why I wanted a new motor as all was good. Anyway, that engine was run only on Shell Premium with the Idimitsu and that is the same for the "new" (Mazda Rebuilt) engine. It has about 60K on it.
What should I (my son) be doing to prolong the life of the engine that is in the car? Why does the internal coolant seal fail and what can we do to ensure the Rebuilt does not suffer the same failure? Thank you!
Rob! i Actually learned something! Never knew about an ApexSeal "SPRING".
Need to watch more of his videos then. Pretty much all of his videos where he puts together motors has them :)
Time to get a rotary for myself...
Yeah, I'm pretty sure that 70% of Rob Dahm videos don't own a rotary, but we still love them.
Excellent Video Rob! It's funny to me that you, as a private tuner, have identified and fixed problems in this motor that Mazda, with $Millions of investment in this engine, hasn't figured out. You are an amazing tuner and I sincerely thank you for your hard work and for sharing your discoveries. I hope to see you out racing some day.
"with $Millions of investment in this engine, hasn't figured out"
Its less that they "havent figured it out", and more that the solutions arent all genuinely viable for a mass market producer that has to abide by global emissions standards.
The Rotary God
The Dorito Deity
The Spin Master
The Triangler Mangler
The No-Outro Bro
The Dowel Stud
Mr ping once said "There is no secret ingredient. Don’t have to. To make something special, you just believe it’s special."
He also said, "Noodle, not noodle."
i've been considering rotary swapping my 944 but i didn't have the knowledge, so i might go along with it now because this video is just enlightening
The thing about the apex seals is interesting to me because you mention "stock internals" if the rest is in order.
I know Mazda 2-piece seals were the first thing to be booted and upgraded back in the 90s when they figured out they crack pretty bad when they do but I wonder how much better 3 piece ones are...just more insurance as you said I'm presuming.
Very interesting vid as always Rob.
You couldn't not cut it that tiny bit short in the end lmao
I pretty sure today somebody sells seals that dont break but not sure if they take 1300hp
There are upsides and downsides to both 2 and 3 piece seals.. 3 piece seal better at low rpm and 2 piece better at high rpm.. the best seals for N.A rotary's are Lannetti ceramic apex seals which are guaranteed for life, lightweight and are reusable, but very expensive.. although don't take well to detonation.. hence why carbon steel are better for turbo rotary's. Racing beat also make great seals.
@@nzuncovered1845 Yeah, ceramic seals work great, until they don't.
Great information Rob. It really blows my mind that people are so secretive about their rotaries. If more people were like you and shared the good, really helpful stuff. Then rotary engines probably wouldn't have such a bad reputation. Sadly there is a lot of misinformation out there. Everything you mentioned makes perfect sense to me. Thanks
I enjoyed this video so much, and it all made so much sense, and so simple to understand. Now I think I'm in love with rotary engines again. I've always thought mass continuing in a circle was way better then reciprocating mass. I've raced 2 stroke dirt bikes growing up (bean oil smells so good) and 2 stroke oil had gotten so good that we were running 100 to 1 mix ratio on synthetic. We just never ran lean on fuel - air ratio. Less oil in the fuel keeps octane higher, and a cleaner combustion chamber. Great video, thanks!
I love how rob doesnt give a dahm about an outro on his vids. "Stop that shit right there im done with the video"🤣🤣🤣🤣🤣
His are the only videos I watch right till the end, as soon as I hear that outro I'm usually done
"I love how rob doesnt give a dahm" I see what you did there 😂
God Dahm it 😂
One day we will see a Gymkhana 12 featuring Rob Dahm's 4 rotor shredding tyres with the hoonicorn. Best believe this is what dreams are made of
Dude if that ever happened it would be insane
That would be great
Ended up here from watching Crighton's 700 CR motorcycle (200hp). That man is brilliant. Good interview with him available.
Dang, Rob with all this science and testing we're gonna have to start calling you Dr. Dorito!
And Prof. Dahm.
I remember way back when, mixing oil into your rotaries gas was common knowledge, but now it's totally unheard of
The dipstick on the RX2 was marked wrong… When it said you were one pint low,, you were two.
Seems to me I heard about that too, a long time ago. I wonder if they "hushed it up" because of fear of alluding to 2-stroke engines. Or maybe they just added the oiling ports on the housing.