So now you need to have an episode on Bob Glidden and welding iron heads to get dual quench areas and small "heart shaped" chambers. A lot of pioneering work was done in his shop. And he never showed his heads to anyone. They were always covered. 10 Pro Stock championships with 5 in a row tells you that he knew what he was doing. Many aftermarket heads emulate Glidden's pioneering work. 👍
If no one ever saw the heads then how did they even know he was legal to race? I hear stories like this all the time and I dont see how that makes sense. Dont they see the engine bay during inspection? Do they just take his word it's a legal size engine? I dont get it.
@@contraband1543 It's possible that if the heads are just meeting the requirements of what getting the requirements of what metal they are, That they wouldn't have to see anything. I would assume they are allowed larger valve size and port work the port work but probably they do inspect the cylinder diameter and the piston compression And the intakeAnd feel delivery system... Outside of that I don't think they care too much about the rest because you really can't cheat any other way with heads unless you change the metal? ... Especially if it's a stock Sized cubic inch class, Heads might not even matter at all.
When the Ford Cleveland heads came out, they had real good combustion chambers. Then to meet emissions Ford adopted a lousy open chamber. The worst thing wrong with the Cleveland heads were the exhaust ports. Every one of the racers spent a lot of time trying to improve them.
@@fustyblatherskite2142 I think I know what you're talking about because I Opened up those exhaust ports... It's almost like for a mission's reasons they just close closed up the exhaust hole and recast the head the same with smaller ports... It's almost like you could see how much to take off off by the casting marks
I don't have a project car, never have, not really any plans to ever build one. I just love how Tony explains the (frankly pretty complex) physics of what's going on in a way that's easy to visualize. Find these videos super interesting.
This is why I watch your videos religiously. You didn't say ANYTHING that I didn't already know, BUT I still learn extremely valuable lessons. Thanks for reminding to look beyond the nuts and bolts and remember to look at the effects on the WHOLE system.
I wish Uncle Tony would have been my shop teacher in High School.('67-'71) I learned, yes , but nothing like what he teaches in these videos. Thanks for doing these.
I just commented the same "I learn from his contents and teachings". He uses details that no others eather skip or don't know themselves. Your looking for specific detail and can't find it in 2022 on the web? I just hate it. Hehe
That concept of exhaust scavenging to help fill the combustion chamber has been used on two stroke diesel’s from conception. Never thought of it in gasoline engines. It makes sense. Thank you for bringing that information to the forefront.
In the 2 stroke Detroit diesel a blower does all the scavenging, there is no "exhaust stroke" all the "intake timing" is in the port size and location. There is one camshaft for the exhaust valves.
Interesting to see what you configure with the combustion chambers- Dave Vizard would be the perfect brain to pick for insights. He also has an appreciation for classic Mopar engineering from those days, and rightly so!
He has several videos out on quench pads, swirl port, valve unshrouding and different degree valve angles with a flow bench numbers to back it up. He has some really in-depth videos where he cut cylinder heads in half and shows you how to port and polish and open up heart-shaped cylinder heads. The man is a wealth of knowledge. 💪
I'm 31 years old and I've never heard this talked about anywhere! The visualization using slaghammer was excellent! The yearning I have for knowledge like this is worse than trying to quit smoking..... I NEED IT. I was going to say " this is what I subscribed for" but I found out I wasn't subbed anymore...
Best way to achieve what you yearn is to get in there, get your hands dirty and just start doing it. I know life, family comes first but try to leave yourself some time for you. Don't take from the family budget but put a little aside for projects and buy, sell, barter parts and services to pay for go fast stuff on a real world budget. It can be done! Just don't wait too late to get started. There is no such thing as waiting too late, the only reason I said that is you are missing out if you don't start now!
Instead of an Edit I just wanted to add this comment... Find some like minded people near you and try to hang out with them. Sometimes one can satisfy their car guy yearnings thru others projects and then you are not even on the hook for the overall cost! It's at least one way to "get into it". Of course I still think you need something of your own as well. Good luck bro. Wish you the best.
@@williamstamper442 Thank you for the kind and inspiring words! I gotta tell ya though, I was born into the "sickness".... Literally. My grandfathers were hot rodders in the 50's, one with cars the other with OTR trucks. One passed when I was 5 the other when I was 9. The majority of what I've learned I've learned by doing what you've stated and through books. I'm a lot like uncle Tony.... Junk everywhere.... Cars everywhere... But it's these little tidd bits of info I wouldn't otherwise think about that I long for. There's only so much that can be learned from a book.
@@DwayneRouthierJr drag strip is another good place to hang out and talk and learn info and maybe a new crew to hang with. If we lived nearby I'd get fired up by your enthusiasm and before you know it we could be knee deep into a project. Try car shows and local shops. Find like minded people to hang out with
@@DwayneRouthierJr I'm 53 and live in Detroit. I'm half hillbilly from eastern Kentucky too. There are like minded people all over our beautiful country called America! Seek and ye shall find!
Great explanation Tony. I was always curious as to the differences in the Boss 429 and the Hemi. Maybe you can do a video on static compression, dynamic compression, and cylinder pressure. There seems to be a lot of confusion in this area. Thanks, and keep it up!
Excellent educational video on combustion chamber dynamics, flow, overlap etc. I really learned something new watching this video. Thank you for your lecture and knowledge. 👍
Fascinating. I learned of the importance of overlap in air cooled aviation engines but it was to cool the exhaust valve, thank you Tony. PS I thought pointing the spark plug towards the exhaust valve gave it the most boom.
Pointing it towards the exhaust valve was to prevent pre-ignition. That's pretty much when the incoming charge gets ignited before it has filled up the combustion chamber. By pointing to the exhaust, the intake charge fills up the cc and is fully ignited, but the rate by which it ignites also becomes a factor. Igniting a full intake charge and the rate by which it burns is directly affected by overlap.
Great video, I keep applying v8 head knowledge to my 3 wheeler. It's like your Harley head, hemi shaped, canted valves, I raised the compression and it definitely helped.
I’m glad you brought forced induction into the vid it’s often assumed it’s exactly the same as n/a but it’s definitely not, my own gm v6 had a closed chamber but with dished pistons with a detonation prone large squish point so I’ve been developing and trying different chambers and the most recent are completely open and it’s got excellent off boost drivability and response and it’s almost detonation proof with 9.3:1 comp running under 30psi of boost on 98octane
Scenario, big block with non hemi heads and a 6-71 supercharger with a Howard’s cam ground for a blower. If the blower is removed, should the cam also be changed? I’m having trouble getting may machinists car tuned
The engine will run fine with a blower grind but it depends on what ha wants the engine for. It wont be optimum for a drag engine but would be great in a heavy car with a stock converter. I ran a turbo cam for a while in a non turbo engine and it worked great, but not as good as the cam that optimized the whole package
The new gen hemi has quench pads and the straight through flow and the engine does not like tones of overlap in the cam. And as a small block chevy guy we pay big attention to combustion chambers . Lots of old pistons for mopars had a quench dome ,it was for closing that open style chamber up
I was 12 and loving engines for the first time. I ran a little Clinton engine with various exhaust pipes and noticed that the thing wouldn’t run without some kind of pipe. My dad built houses so I had piles of copper pipe to play with so I would hammer out pipes that looked Kool and fasten them it the little Clinton engine. What I found was a piece of 3/4 inch ran the best. But if I held a pices if pipe about 1/8 inch from the exhaust port it would run but moving farther away the engine would sputter and quit. Later in college physics class I learned why. Interesting you bring this up today. Boy I love high performance engines! Can’t wait to see your development on those heads.
Uncle Tony, your explanation makes total sense to me! I have read a lot of textbooks, articles and always seek good information. This video of yours is an out of the park home run! I have learned a lot from you. Thank you for sharing such good information!
A couple other things you don’t hear much about the SBM is that the plug is about as centrally located in the chamber as you can get for a wedge head, and the valves open closer to the centerline (max width) of the bore for less valve shrouding. But the factory ports aren’t ‘great’ so they need all the help they can get, as in, swap ported 360s on! lol
One way to evaluate the effectiveness of a combustion chamber is the spark advance needed for best power. According to mopar performance, best for SB mopar is 35, Hemi 36 and BB 38 degrees total. In a Magnum it's about 32.
Question, if you're going after a max performance 318 then why would you even mess around with them junk head's? I mean you could port those until the cows come home and still aren't going to flow worth a crap! And TrickFlow just came out with some killer small block Chrysler head's! So why would ya? Them heads will never be worth the time and effort and money you'll put into them, then theirs the weight savings of going with an aluminum head as well, much more efficient chamber design's, etc.etc.etc.
I think it follows with the "run what ya have" mentality. Sure, a stock set of heads will flow poorly compared to an aftermarket set of heads, but not everyone has aftermarket heads money. It's a learning curve to learn to port heads and a great self teaching tool. Most people wouldn't believe the seat of the pants improvement you'd get by porting a set of stock heads and doing some gasket matching.
David Visard discusses this in his books and on his channel. It is sometimes called scavenging, a term more often associated with 2 strokes. Thats also why cleaning up the intake valve bole and a 5 angle valve job has disproportionate increases in performance than one may expect.
I think tony is genius! Down to earth and truly caught up in his presentation. If he taught math i would probably learn math- and enjoy it, Impossible!!!
I always figured the quench parts of the head were to raise the compression without having a big flame-front blocking mountain on the piston as well as getting some swirl; I've never heard of the concept of it influencing the overlap but as soon as I heard it explained it made perfect sense! Thanks for giving us gear-heads something new to ponder!
I love how much information you give thank you.! I translated to my Volkswagens and it is extremely helpful. VW has a long intake manifold and everyone says get dual carbs but I didn't listen and got a single two barrel.. so I need a strong signal to pull the fuel from the center carburetor and now I know how to fix my problem you're a genius
Very informative and helpful. On My '68 396 BBC (bored to 402) short block Im running some late 70's open chamber large OVAL port heads from a dump truck 366 bbc w/ SMALL valves ( 1.92 intake /1.64 Exhaust). The small valves give REALLY nice low end torque for taking off from a stop but arent designed for much above 4500 RPM. I found a set of 68 closed chamber Heads with the 2.08 int/1.75 exh more suited the the original 396 power levels which i may swap at some point. In a 58 Chevy Bel Air low RPM is just fine though...w/ 5000 RPM roller cam
Tony , best video you've made! ,, look at Bob Glidden 351C pro stock heads ... basically they have been copied by every automaker ... I think you'll need to incorporate port bias to optimize exhaust pulse assistance with the intake as you'll have to have a far more open chamber near the plug side. Anti-reversion added to ex port will help too. Welding and grinding that cheap iron is going to be dreadful...any aluminum versions available?
Now ya just blew my mind. I always thought overlap was the delay between the exhaust valve closing and the intake opening. I still can’t picture this yet. Piston traveling down = intake Piston traveling up = exhaust
This is a very good episode Tony!!! The movement of exhaust gas through the exhaust system, causing a vacuum behind each pulse that helps to initiate the flow of the fresh air/fuel mix into that cylinder, because of the breif moment of both valves being slightly open at the same time - aka- valve overlap.... When I was going through A&P school, the instructors explained that valve overlap was an event that took place to cool the exhaust valves... Looking back at that training, I remember that everything was to emphasize the reliability of airplane equipment.. A very small emphasis of how to tune for more power and speed was being taught in those schools... But I now tend to believe the reasoning that You give here Tony... The overlap is a function to improve responsiveness and performance of 4-stroke reciprocating engines...
That is actually wrong information about the vacuum behind the exhaust gas column. It used to be believed that way a long long time ago, but has been disproven since then. The moment the pressure wave from the exhaust column exits the primary pipe into a chamber with a volume change, there is a negative pressure reflection backwards towards the valve due to that volume change. That negative pressure (vacuum) wave then accelerates the charge towards the exhaust valve. The same happens on the intake side when the positive pressure wave from the intake valve closing reflects and goes back towards the plenum. The moment it hits the plenum a vacuum wave (negative pressure) goes back again towards the intake valve. Depending on the length of the runner plus port it will create an additional charge effect. This is called pressure wave tuning.
It's called making things simple so that anyone can understand. I've done several videos on sonic pulses and waves, mostly having to do with intake manifolds.
@@UncleTonysGarage it’s nonetheless wrong from a physics standpoint. You can also explain what I said in a fairly simple way, especially standing in front of an engine and the headers. Exactly what you said in the video has been commonly believed for a long time and many people still believe it today, but it’s a completely different concept to what actually happens.
it's not strictly necessary for a 4 stroke too, you just can get more power out of cc. additionally you can drive scooters around with header hanging off. plup plup plup plup plup, still better power/cc ratio than 1981 usa factory v8.
as i understand there is not a low pressure wave following the particles instead there is a low pressure wave going against the direction of propagation when area(velocity and pressure) is changed. please correct me if i am wrong
Excellent video and valuable insights. Love how it was all explained! Supercharged applications I totally agree that there is always a high pressure gradient available to move things in the right direction but turbocharged comes with inherent drive/backpressure that varies greatly with the setup and across the operating range- making scavenging, or residual exhaust gas which is what's left if you don't scavenge the rest of the chamber, displacing what would otherwise be filled in the following intake stroke. What you're describing is what we've attributed to some significant changes in power psi and response in turbo applications with an exhaust manifold change alone. That effect scales well with the valve overlap and whether the overlap phase is a good thing or a bad thing
Hey Uncle Tony! I enjoy videos like this where you explain things. Unfortunately, I must have a fixation on cubic displacement ( "No replacement for displacement", right?) Maybe you explained this before but why build a 318 when you can have the extra displacement of a 340 or 360? Would a 340/360 bump you up to another bracket class? I'm trying to learn something here...
A natural instructor! Could give training lectures on any scale to any audience! World class !! A snazzy suit or casual, he could teach surfing ! A very- very interesting instructor. He makes learning fun!!!
Another educational jem....thank you Unk ! Question....Larger valves gets the exhaust and intake closer together. Will that affect the overlap to any real degree?
Uncle Tony. The absolute best example of overlap and collector design is the rotary engine. If you talk just overlap 2 stroke is where you look. There can be 100% plus change in power out put along with rpm of said power out put by the over lap and collector and header design in a rotary and 2 stroke
Like an expansion chamber on a 2-stroke but without the reverse cone to force the fuel/air mixture back into the cylinder. Hey Tony, a great thing to add to this would be an explanation on how motorcycles have smaller combustion chambers (and hence shorter heat path) allowing higher compression ratios on pump gas. Another interesting thing would be an explanation of Anti-Reversion headers. There were some really good ones for VW/Porsche Type 4s in the early 80s that outperformed standard headers (there were rotary scavenge designs as well). These anti-reversion headers had a sort of cone with small aperture facing away from the port so if gas tried to revert back to the cylinder it blocked reverse flow. This is done sometimes now by having header ports a bit larger than cylinder head exhaust ports creating a sharp edge. But this tech changes. When I was a kid racing go karts we didn't use expansion chambers but just exhaust megaphones. So, we fabbed up port plates with semi-circular protrusions into the crankcase to decrease its internal volume thereby raising scavenge pressure to the intake port. These were referred to as "Rabbit Ear Stuffers". When chambers started showing up these seem to have gone away as the chamber was used to suck the fuel/air mixture out of the crankcase (via the transfer/intake and then exhaust port) and tuned to length to push the mixture back into the cylinder after the intake port closes. It was/is effectively a form of supercharging as it can fill the cylinder with more than a cylinder's volume of fuel/air mixture. It is so long ago now that my Power Products, Westbend, and McCullough engines (MC10) are actually antiques. Ha Ha
I’ve never taken an engine apart or done any of this stuff but I love UTG! I’m just a home noodles trying to learn. I changed my timing belt on my 99 CRV and now I realized I got my intake cam off by one tooth. It runs but uses too much gas. Now I understand the importance of the intake and exhaust valve timing.
Wow! That was a really good video Tony. Job well done! Your dead on right about most people don’t pay attention much less know a whole lot about that chamber and gas flowing issue during overlap. Big power in the overlap and if the chamber is a good one, in your own words, the magic happens.
That definitely explains the pent-roof chamber thing...They wanted the benefits of the hemi's canted-valve setup with the more-direct intake signaling, but they wanted the non-valve areas closed down as much as they can. Hadn't thought about it like that before.
Most interesting Tony. It's almost like listening to my grandfather explain the very same things years ago to me, (I'm almost 69 now). About 20 years ago I created a set of 400M heads with "squish" areas like a 460, but built for the 531/400M engines. They ended up working very well. I have a set off, and if you would like I will dig them out and take a few pics and send them to you for any sort of reference that they might be good for.
Excellent information. Really great to bring this up and mind people about the combustion chamber valve placement valves, valve sizing ports. All of that stuff. The cylinder head truly is one of the best places to make power from
Tony I'm not a mopar guy and not a chevrolet guy, but always been a fan of closed chambers, compression and cam timing with intake closing being the most important event. And testing is the only way to find the sweet spot on the cam design. I haven't bought an off the shelf camshaft for my own projects in over 30 years. Yet with all I said, I know there is much more to be learned about combustion chambers design. Ok I'll let the cat out of the bag, I'm a lowly oldsmobile guy. I have a stock stroke .030 bore 455 that makes 625hp/640tq on the pump with a single carb single plane. Currently running a custom crane hyd roller with a standard iron distributor drive gear on the billet shaft so I didn't have to worry about bronze gears. The cam is based on LS chevrolet lobes, it's .620ish lift 255/260ish @ .050 duration on a 110 lobe sep. I know there is more power if I tweak the grind but I'm tired of juice lifters and wanna go solid roller next. Goal is 700hp normally aspirated all Olds, and I'm on my way. The info in this vid is just part of the answer but well done presentation and I hope others pick up on what you are throwing down!
Instead of doing an Edit on my own comment thought I would just throw out another one. All this combustion chamber talk revitalizes my desire to build a custom head for the brand of my choice, which is Oldsmobile, and what I want to achieve is a canted valve, a la big block chev (the porcupine) and fit them within the space given. Reason is this cross flow theory/dynamics Tony is talking about in the video, but doing so by unshrouding the flow around the outer sides of the valves. Valve shrouding kills more power than many other things when the inherit design is a 10 degree head with the valves in the same plane. I believe a canted valve in an aftermarket aluminum rough casting cyl head for Olds may finally achieve the 400+cfm mark to make this engine more competitive. I could be wrong with this but sure hope to try it before I die. Around 1969 Olds engineers designed a near "hemi" design based on a standard 455 short block. I'm a die hard Olds guy and forget the freaking designation they gave this engine. Maybe it was called a W-43? I don't know I gotta look it up... But they actually built a running version decked out with stock accessories of the time to actually go into production. But 1971 and emissions kinda killed it. I believe they only built 2 or 3 of them. One is on display in the GM car show trailer showing innovations and different engines the company built over the years. Far as I know there are no running examples out there in the real world as of 2022. Thing is I wanna make a cyl head out of aftermarket aluminum to kinda achieve the same thing. I'm not gonna set the world on fire but if I can bring a new found respect for the Olds name then I'll be happy.
Great video. The primary header tube length and diameter in conjunction with the sizings of the collector create a low pressure pulse. Plus the column of hot air racing away from the exh port draws or sucks the initial incoming intake charge into the cylinder. Yes small amounts of raw fuel air are siphoned away but it kick starts the int charge moving. Add that to ram tuning the arrival of the fresh int charge pooling up behind the intake valve and you gain serious horsepower. Ram tuning both int and exh to certain rpm ranges. Extra compression almost always adds more power too across the rpm range. The gigantic amount of deep scientific variables is a key reason I love drag racing so much
I'm running a Cleveland with 2v heads and wanting to figure out how to "close" them. Wish I could afford to change over to 4v closed or , in my happy dreams , Aus 3v heads. I e thought about filling with weld but then came to my senses when I thought about the weld breaking off and trashing a rare engine! I hope UT can make those open chambers into closed and even chamber cc across the bank! Cant wait to see how its done!!!
Very good video, when I was in school my teacher tought us ,cam profile, overlap are your starting points ,and your video like he did explaining why. Thanks for the video.
Now I am filled with questions like "how does this then relate to you picking camshaft?" and "wouldn't a raised piston of some design be the best way to tackle the combustion chamber shrinkange or would it hurt?" or how about this being the reason behind that idea that an exhaust system promotes more of that pulling action thru the chamber, single vs dual... all kinds of questions now that this little piggy must know the answers to! haha I like these learn em videos.
a raised or domed piston (to create compression) can impede airflow into a cylinder and sometimes can block the flow of the spark--some domed pistons come with a "flame tunnel" milled into the dome. but it is interesting how many will pick a camshaft design to help the ports flow more air by keeping the valve open longer....yet if the combustion chamber doesn't burn well enough, you're just moving raw fuel in and out. Now, if you can do a good angle grinding job on the valve seats in the head and on the back of the valve face, you can help the port flow more air/fuel at low valve lifts. which will create the effect of more overlap at the cam as the intake valve begins to open off the seat and the exhaust valve returns to the seat. so you can have less overlap in the camshaft profile if vacuum to drive power accessories was an issue.
When I listen to you talk cars and mechanic stuff I harken back to the days when I went to school to learn the trade. Bill Pfeifer was my instructor. Real cool old school no nonsense kinda guy who could explain the whole lesson in basic words. The only difference between him and these videos is you never mention "Joe Blow's Garage down the street".
Hi Tony Great video, I love in depth engine tuning, and have been playing with engines about 30 years now. To be fair though David Vizard does also talk all about this stuff and is also a wealth of knowledge . Great Video, loved it. 👍👍👍👍
David is a friend of mine, and we've done a couple of shows together. He's been under the weather lately, but I hope to do something with him again soon.
Very well done video brother. I think I am going to keep my 318 in my dodge shortbox pickup but I would like to learn how to port heads is there a good casting number small block Mopar head. Cuz I am going to keep my 440 727 for a 66-67 charger or a 70 superbee my dream dodges. And I want to get some power out of my small block dodge
I'm confused. The Hemi design improves flow by (essentially) placing the intake valves in-line with the exhaust valves, but the lack of a quench pad hampers flow. So is it good or bad, or what?
Not sure if you will see this Uncle Tony but interesting enough back in Hondas glory days they used open chamber heads on there type R, B series engines. There was always a debate on what was better but my opinion was always they knew what they were doing. (Highest hp per litre N/A production engine records for 15 years until Ferrari finally beat them). I think they went open because it helped de shroud the valves. They flowed like crazy and reved in the 8-9k range . Also just as interesting spoon was running such high RPMs on the B series they had issues with pistons out accelerating the flame front. Maybe another reason for open chamber?
On an LS3 engine, does a .010 thinner head gasket only help the engine run more efficiently or does it gain hp/to. Calculations say .3 tenths compression change.
When my mentor Clif Kolostow worked at Ed Miller's in the late 60's early 70's they would take brand new 340's and mill the heads .060" That turned the open chamber head into a closed chamber head. I think they were more interested in upping the compression, but what you are talking about here was no doubt a part of why they were doing that. One thing is for sure. Their 340's ran better than most. Like MoPar said, "340...the Big Bore Hunter"
I've learned what Uncle T is talking about over many years of going to Bonneville... As Gray Baskerville called it, The Great White Dyno. Dollar per Hp, the recycled blown fuel Hemis that guys use have the most bang for the buck. The two fastest Blown Fuel Roadsters at Bonneville are nitro powered Hemis... one is naturally aspirated on nitro and actually went faster than the blown car. The N/A gas classes are ruled by wedge type engines. Blown gas powerplants seem to do slightly better with non Hemi designs as well. One friend of ours ran a 500 inch TFX nitro fuel Hemi on 4 cylinders on one bank and the car went just as fast as the full configuration. They estimated it had to be making 500-600hp per cylinder to go the speed it did with 250cu. in (E record 303mph). Car number 125 has blown fuel competition coupe records starting at AA 305.241mph A 305.607mph B 311.149mph C 300.022mph D 296.278mph E 303.231mph Keep in mind these engines are de-tuned from a drag racing setup... they have to last up to about 80 seconds under load each pass and it takes 2 pass average to set a record. Also Bonneville is around 4000ft above sea level.
Exactly what I'm setting up to do is welding to fill in key spots of the combustion chamber for a better burn and round all sharp spots for ceramic coating and modify a dome pistons with a unique pistons shape. I'm only truing the heads. 045 cast steal. Heads crack and fail when shaving to much for a certain combustion raio. Filling in parts of combustion chamber cause of what IL experimenting with.
Tony You forgot to tell your audience why and how the 5th cycle does what it does nd why - So the Lobe Separation Angle generates the overlap event = the 5th cycle The closer the LSA the more overlap and wider the LSA the less overlap The squish/quench area is the most important part of all wedge heads and the optimum for that is zero clearance when the engine is running a max RPM - the problem then becomes the trapped end gasses between the piston and the head at TDC - but there is also a solution for that called the "V" Groove - With the proper amount of swirl and the v groove you can run 12 to 1 on pump gas
Hemisphereical combustion chambers, 4 valves per cylinder, and modest turbocharger is how my car makes 300 hp from 139 cubic inches. In a 3300 lb wagon, it will get 26 - 28 MPG.
OK. Now, how does the 30 degree intake valve angle used by Pontiac, and followed by Buick and AMC, play into this? The 30 degree valve seat flows from 0.030" lift instead of 0.050" lift with the standard 45 degree angle, having the effect of more cam than is actually there. Doesn't flowing sooner give the effect of just that much more overlap?
this video is pretty good but theres a few things id add, im not suprised that anyone would be lacking knowledge on this stuff becase of how sparce the info is and how hard it is to find. the hemi chamber bolth has the least serface aria for a given volume whitch helps retain heat in the combustion charge whitch ofc is responsable for the power you make and due to this it wont form hotspots adding to the spark plug point you made. the performince also has to do with the fact you can fit massive valves to the engine whitch allows large flow along with the geomitry advantage you mentioned. open combustion chabers came about becase the lack of high octane gas so they wanted to decrease surface aria and compression whitch also aids in emmisions kinda. high surface aria reduces the temp of combustion whitch does decrease nox emmisions. though the increased swirl and turbulace also helps with emmisions due to having a more homogonus and complete combustion. this also aids in high rpm performince sence you have alot less time to complete the combustion event so any added turbulince helps. though high rpm induces turbulance due to the increased flow whitch is one of the reasons why why we see hemis perform pretty well at high rpms. its always intresting to me that designs like the hemi and the rotary whitch i conciter to be on opposite sides of the spectrum due to the rotarys large surface aria per volume making combustion happen very slowly. bolth of them suffer from a large lack of turbulace.
Why do you have a traffic cone on the work bench. I'll see myself out!
LOLOLOL HAHAHAHA 😆
Can't you see? That's clearly a Tennessee Vols megaphone.
Orange you guys going to be serious?
That's not a traffic cone! It's a Turboencapulator!
It's for autocross later
So now you need to have an episode on Bob Glidden and welding iron heads to get dual quench areas and small "heart shaped" chambers. A lot of pioneering work was done in his shop. And he never showed his heads to anyone. They were always covered.
10 Pro Stock championships with 5 in a row tells you that he knew what he was doing. Many aftermarket heads emulate Glidden's pioneering work. 👍
If no one ever saw the heads then how did they even know he was legal to race?
I hear stories like this all the time and I dont see how that makes sense.
Dont they see the engine bay during inspection? Do they just take his word it's a legal size engine? I dont get it.
@@contraband1543 It's possible that if the heads are just meeting the requirements of what getting the requirements of what metal they are, That they wouldn't have to see anything. I would assume they are allowed larger valve size and port work the port work but probably they do inspect the cylinder diameter and the piston compression And the intakeAnd feel delivery system... Outside of that I don't think they care too much about the rest because you really can't cheat any other way with heads unless you change the metal?
... Especially if it's a stock Sized cubic inch class, Heads might not even matter at all.
Bob gliddens clevelands ran like a Big block 😎
When the Ford Cleveland heads came out, they had real good combustion chambers. Then to meet emissions Ford adopted a lousy open chamber. The worst thing wrong with the Cleveland heads were the exhaust ports. Every one of the racers spent a lot of time trying to improve them.
@@fustyblatherskite2142 I think I know what you're talking about because I Opened up those exhaust ports... It's almost like for a mission's reasons they just close closed up the exhaust hole and recast the head the same with smaller ports... It's almost like you could see how much to take off off by the casting marks
I don't have a project car, never have, not really any plans to ever build one. I just love how Tony explains the (frankly pretty complex) physics of what's going on in a way that's easy to visualize. Find these videos super interesting.
This is why I watch your videos religiously. You didn't say ANYTHING that I didn't already know, BUT I still learn extremely valuable lessons. Thanks for reminding to look beyond the nuts and bolts and remember to look at the effects on the WHOLE system.
I have only heard one other person talk about this subject. Smokey Yunick talked about this back when he was doing a column in Circle Track Magazine.
And that's exactly where I learned about this 40 years ago
I wish Uncle Tony would have been my shop teacher in High School.('67-'71) I learned, yes , but nothing like what he teaches in these videos. Thanks for doing these.
I just commented the same "I learn from his contents and teachings". He uses details that no others eather skip or don't know themselves. Your looking for specific detail and can't find it in 2022 on the web? I just hate it. Hehe
This was super informative and well explained. Thank you!
Uncle Tone's mechanical talks are the ultimate mental health therapy!...😎
That concept of exhaust scavenging to help fill the combustion chamber has been used on two stroke diesel’s from conception. Never thought of it in gasoline engines. It makes sense. Thank you for bringing that information to the forefront.
In the 2 stroke Detroit diesel a blower does all the scavenging, there is no "exhaust stroke" all the "intake timing" is in the port size and location. There is one camshaft for the exhaust valves.
Im doing the same thing with a hi output 318. I put 1.88 valves and ported 302 heads. Fun winter project.
Interesting to see what you configure with the combustion chambers- Dave Vizard would be the perfect brain to pick for insights. He also has an appreciation for classic Mopar engineering from those days, and rightly so!
He has several videos out on quench pads, swirl port, valve unshrouding and different degree valve angles with a flow bench numbers to back it up. He has some really in-depth videos where he cut cylinder heads in half and shows you how to port and polish and open up heart-shaped cylinder heads. The man is a wealth of knowledge. 💪
I'm 31 years old and I've never heard this talked about anywhere! The visualization using slaghammer was excellent! The yearning I have for knowledge like this is worse than trying to quit smoking..... I NEED IT.
I was going to say " this is what I subscribed for" but I found out I wasn't subbed anymore...
Best way to achieve what you yearn is to get in there, get your hands dirty and just start doing it. I know life, family comes first but try to leave yourself some time for you. Don't take from the family budget but put a little aside for projects and buy, sell, barter parts and services to pay for go fast stuff on a real world budget. It can be done! Just don't wait too late to get started. There is no such thing as waiting too late, the only reason I said that is you are missing out if you don't start now!
Instead of an Edit I just wanted to add this comment... Find some like minded people near you and try to hang out with them. Sometimes one can satisfy their car guy yearnings thru others projects and then you are not even on the hook for the overall cost! It's at least one way to "get into it". Of course I still think you need something of your own as well.
Good luck bro. Wish you the best.
@@williamstamper442 Thank you for the kind and inspiring words! I gotta tell ya though, I was born into the "sickness".... Literally. My grandfathers were hot rodders in the 50's, one with cars the other with OTR trucks. One passed when I was 5 the other when I was 9. The majority of what I've learned I've learned by doing what you've stated and through books. I'm a lot like uncle Tony.... Junk everywhere.... Cars everywhere... But it's these little tidd bits of info I wouldn't otherwise think about that I long for. There's only so much that can be learned from a book.
@@DwayneRouthierJr drag strip is another good place to hang out and talk and learn info and maybe a new crew to hang with. If we lived nearby I'd get fired up by your enthusiasm and before you know it we could be knee deep into a project. Try car shows and local shops. Find like minded people to hang out with
@@DwayneRouthierJr I'm 53 and live in Detroit. I'm half hillbilly from eastern Kentucky too. There are like minded people all over our beautiful country called America! Seek and ye shall find!
Great explanation Tony. I was always curious as to the differences in the Boss 429 and the Hemi. Maybe you can do a video on static compression, dynamic compression, and cylinder pressure. There seems to be a lot of confusion in this area. Thanks, and keep it up!
Excellent educational video on combustion chamber dynamics, flow, overlap etc. I really learned something new watching this video. Thank you for your lecture and knowledge. 👍
Fascinating. I learned of the importance of overlap in air cooled aviation engines but it was to cool the exhaust valve, thank you Tony.
PS I thought pointing the spark plug towards the exhaust valve gave it the most boom.
I heard that to. I remember guys indexing the plugs back in the day.
Pointing it towards the exhaust valve was to prevent pre-ignition. That's pretty much when the incoming charge gets ignited before it has filled up the combustion chamber. By pointing to the exhaust, the intake charge fills up the cc and is fully ignited, but the rate by which it ignites also becomes a factor. Igniting a full intake charge and the rate by which it burns is directly affected by overlap.
Great video, I keep applying v8 head knowledge to my 3 wheeler. It's like your Harley head, hemi shaped, canted valves, I raised the compression and it definitely helped.
Nobody talks about how awesome you are. Thank you for another mind opening video.
I’m glad you brought forced induction into the vid it’s often assumed it’s exactly the same as n/a but it’s definitely not, my own gm v6 had a closed chamber but with dished pistons with a detonation prone large squish point so I’ve been developing and trying different chambers and the most recent are completely open and it’s got excellent off boost drivability and response and it’s almost detonation proof with 9.3:1 comp running under 30psi of boost on 98octane
I wish somebody would have explained this to me like you just did 30 years ago! Would have saved so much trial and error. Thanks
Scenario, big block with non hemi heads and a 6-71 supercharger with a Howard’s cam ground for a blower. If the blower is removed, should the cam also be changed? I’m having trouble getting may machinists car tuned
The engine will run fine with a blower grind but it depends on what ha wants the engine for. It wont be optimum for a drag engine but would be great in a heavy car with a stock converter. I ran a turbo cam for a while in a non turbo engine and it worked great, but not as good as the cam that optimized the whole package
@@superrodder2002 it’s in a T bucket, mild stall, C6, 4.30s. It’s a cruiser
I always learn something (that I consider to be) important when I watch your presentations.
The new gen hemi has quench pads and the straight through flow and the engine does not like tones of overlap in the cam. And as a small block chevy guy we pay big attention to combustion chambers . Lots of old pistons for mopars had a quench dome ,it was for closing that open style chamber up
I was 12 and loving engines for the first time. I ran a little Clinton engine with various exhaust pipes and noticed that the thing wouldn’t run without some kind of pipe. My dad built houses so I had piles of copper pipe to play with so I would hammer out pipes that looked Kool and fasten them it the little Clinton engine. What I found was a piece of 3/4 inch ran the best. But if I held a pices if pipe about 1/8 inch from the exhaust port it would run but moving farther away the engine would sputter and quit. Later in college physics class I learned why. Interesting you bring this up today. Boy I love high performance engines! Can’t wait to see your development on those heads.
Please continue to shoot videos on your progress I am very interested in this sounds like a really cool project
I'm planning on a full build for this coming spring
Tony,
What a great way to explain how engines work!
I love the details of stuff like this - learn so much from your videos Tony!
Great explanation Tony, I learn a lot for free, thanks!
Uncle Tony, your explanation makes total sense to me! I have read a lot of textbooks, articles and always seek good information. This video of yours is an out of the park home run! I have learned a lot from you. Thank you for sharing such good information!
A couple other things you don’t hear much about the SBM is that the plug is about as centrally located in the chamber as you can get for a wedge head, and the valves open closer to the centerline (max width) of the bore for less valve shrouding. But the factory ports aren’t ‘great’ so they need all the help they can get, as in, swap ported 360s on! lol
One way to evaluate the effectiveness of a combustion chamber is the spark advance needed for best power. According to mopar performance, best for SB mopar is 35, Hemi 36 and BB 38 degrees total. In a Magnum it's about 32.
@@vipottaja good points but it also depends on bore size. Typically bigger bore you need more advance all else being equal.
@@vipottaja like Chevy Vortec heads versus anything they made before them.
Question, if you're going after a max performance 318 then why would you even mess around with them junk head's? I mean you could port those until the cows come home and still aren't going to flow worth a crap! And TrickFlow just came out with some killer small block Chrysler head's! So why would ya? Them heads will never be worth the time and effort and money you'll put into them, then theirs the weight savings of going with an aluminum head as well, much more efficient chamber design's, etc.etc.etc.
I think it follows with the "run what ya have" mentality. Sure, a stock set of heads will flow poorly compared to an aftermarket set of heads, but not everyone has aftermarket heads money. It's a learning curve to learn to port heads and a great self teaching tool. Most people wouldn't believe the seat of the pants improvement you'd get by porting a set of stock heads and doing some gasket matching.
David Visard discusses this in his books and on his channel. It is sometimes called scavenging, a term more often associated with 2 strokes. Thats also why cleaning up the intake valve bole and a 5 angle valve job has disproportionate increases in performance than one may expect.
I think tony is genius! Down to earth and truly caught up in his presentation. If he taught math i would probably learn math- and enjoy it, Impossible!!!
I always figured the quench parts of the head were to raise the compression without having a big flame-front blocking mountain on the piston as well as getting some swirl; I've never heard of the concept of it influencing the overlap but as soon as I heard it explained it made perfect sense! Thanks for giving us gear-heads something new to ponder!
I love how much information you give thank you.! I translated to my Volkswagens and it is extremely helpful. VW has a long intake manifold and everyone says get dual carbs but I didn't listen and got a single two barrel.. so I need a strong signal to pull the fuel from the center carburetor and now I know how to fix my problem you're a genius
Great tutorial Tony love to see how you weld those heads to get the desired results thanks mate
Very informative and helpful. On My '68 396 BBC (bored to 402) short block Im running some late 70's open chamber large OVAL port heads from a dump truck 366 bbc w/ SMALL valves ( 1.92 intake /1.64 Exhaust). The small valves give REALLY nice low end torque for taking off from a stop but arent designed for much above 4500 RPM. I found a set of 68 closed chamber Heads with the 2.08 int/1.75 exh more suited the the original 396 power levels which i may swap at some point. In a 58 Chevy Bel Air low RPM is just fine though...w/ 5000 RPM roller cam
Tony , best video you've made! ,, look at Bob Glidden 351C pro stock heads ... basically they have been copied by every automaker ... I think you'll need to incorporate port bias to optimize exhaust pulse assistance with the intake as you'll have to have a far more open chamber near the plug side. Anti-reversion added to ex port will help too. Welding and grinding that cheap iron is going to be dreadful...any aluminum versions available?
Now ya just blew my mind. I always thought overlap was the delay between the exhaust valve closing and the intake opening.
I still can’t picture this yet.
Piston traveling down = intake
Piston traveling up = exhaust
Love your engine stuff ! Often thought provoking and achievable without remortgaging the house 👍
I milled a pair of 360 heads till the combustion chamber is nearly closed. Maybe not wise, but they didn't crack. They work great on my 318.
This is a very good episode Tony!!! The movement of exhaust gas through the exhaust system, causing a vacuum behind each pulse that helps to initiate the flow of the fresh air/fuel mix into that cylinder, because of the breif moment of both valves being slightly open at the same time - aka- valve overlap.... When I was going through A&P school, the instructors explained that valve overlap was an event that took place to cool the exhaust valves... Looking back at that training, I remember that everything was to emphasize the reliability of airplane equipment.. A very small emphasis of how to tune for more power and speed was being taught in those schools... But I now tend to believe the reasoning that You give here Tony... The overlap is a function to improve responsiveness and performance of 4-stroke reciprocating engines...
Yes! Lets see how much gusto a 318 can have!
Ohh my favorite topic! Cylinder heads and intakes.
Cheers Tony 🏁
That is actually wrong information about the vacuum behind the exhaust gas column. It used to be believed that way a long long time ago, but has been disproven since then. The moment the pressure wave from the exhaust column exits the primary pipe into a chamber with a volume change, there is a negative pressure reflection backwards towards the valve due to that volume change. That negative pressure (vacuum) wave then accelerates the charge towards the exhaust valve. The same happens on the intake side when the positive pressure wave from the intake valve closing reflects and goes back towards the plenum. The moment it hits the plenum a vacuum wave (negative pressure) goes back again towards the intake valve. Depending on the length of the runner plus port it will create an additional charge effect. This is called pressure wave tuning.
It's called making things simple so that anyone can understand. I've done several videos on sonic pulses and waves, mostly having to do with intake manifolds.
@@UncleTonysGarage it’s nonetheless wrong from a physics standpoint. You can also explain what I said in a fairly simple way, especially standing in front of an engine and the headers. Exactly what you said in the video has been commonly believed for a long time and many people still believe it today, but it’s a completely different concept to what actually happens.
What you're saying is true. What I'm describing is the effect.
it's not strictly necessary for a 4 stroke too, you just can get more power out of cc. additionally you can drive scooters around with header hanging off. plup plup plup plup plup, still better power/cc ratio than 1981 usa factory v8.
as i understand there is not a low pressure wave following the particles instead there is a low pressure wave going against the direction of propagation when area(velocity and pressure) is changed. please correct me if i am wrong
BBC tall deck " peanut" heads came to mind when watching this video. The old dump truck motors.
I’ve seen there are different thicknesses of head gaskets, how much can u affect the compression ratio by using a thick gasket versus a thin one?
Excellent video and valuable insights. Love how it was all explained! Supercharged applications I totally agree that there is always a high pressure gradient available to move things in the right direction but turbocharged comes with inherent drive/backpressure that varies greatly with the setup and across the operating range- making scavenging, or residual exhaust gas which is what's left if you don't scavenge the rest of the chamber, displacing what would otherwise be filled in the following intake stroke. What you're describing is what we've attributed to some significant changes in power psi and response in turbo applications with an exhaust manifold change alone. That effect scales well with the valve overlap and whether the overlap phase is a good thing or a bad thing
Hey Uncle Tony!
I enjoy videos like this where you explain things. Unfortunately, I must have a fixation on cubic displacement ( "No replacement for displacement", right?) Maybe you explained this before but why build a 318 when you can have the extra displacement of a 340 or 360? Would a 340/360 bump you up to another bracket class? I'm trying to learn something here...
A natural instructor! Could give training lectures on any scale to any audience! World class !! A snazzy suit or casual, he could teach surfing ! A very- very interesting instructor. He makes learning fun!!!
There’s some good videos on TH-cam that shows intake and exhaust flow on engine’s with clear cylinder heads
Another educational jem....thank you Unk !
Question....Larger valves gets the exhaust and intake closer together. Will that affect the overlap to any real degree?
YES, I thought I was the only 1 who got the idea to weld and wedge the combustion chambers down to about 60cc from 64. kicked my sbc up to like 10.2:1
My buddy had a 340 that dynoed in the low 600hp range back in the 90s so I would except a max effort 318 should be close to that number today.
Thanks for all the information and sharing it with everyone. Take care 👍
Uncle Tony. The absolute best example of overlap and collector design is the rotary engine. If you talk just overlap 2 stroke is where you look. There can be 100% plus change in power out put along with rpm of said power out put by the over lap and collector and header design in a rotary and 2 stroke
Like an expansion chamber on a 2-stroke but without the reverse cone to force the fuel/air mixture back into the cylinder. Hey Tony, a great thing to add to this would be an explanation on how motorcycles have smaller combustion chambers (and hence shorter heat path) allowing higher compression ratios on pump gas. Another interesting thing would be an explanation of Anti-Reversion headers. There were some really good ones for VW/Porsche Type 4s in the early 80s that outperformed standard headers (there were rotary scavenge designs as well). These anti-reversion headers had a sort of cone with small aperture facing away from the port so if gas tried to revert back to the cylinder it blocked reverse flow. This is done sometimes now by having header ports a bit larger than cylinder head exhaust ports creating a sharp edge. But this tech changes. When I was a kid racing go karts we didn't use expansion chambers but just exhaust megaphones. So, we fabbed up port plates with semi-circular protrusions into the crankcase to decrease its internal volume thereby raising scavenge pressure to the intake port. These were referred to as "Rabbit Ear Stuffers". When chambers started showing up these seem to have gone away as the chamber was used to suck the fuel/air mixture out of the crankcase (via the transfer/intake and then exhaust port) and tuned to length to push the mixture back into the cylinder after the intake port closes. It was/is effectively a form of supercharging as it can fill the cylinder with more than a cylinder's volume of fuel/air mixture. It is so long ago now that my Power Products, Westbend, and McCullough engines (MC10) are actually antiques. Ha Ha
best...or one of the top ten tech episodes...love it...i wish you were a big block chevy man....
I absolutely adore the Big Block Chevy, but my investment in time and parts is all centered around Mopars
I’ve never taken an engine apart or done any of this stuff but I love UTG! I’m just a home noodles trying to learn.
I changed my timing belt on my 99 CRV and now I realized I got my intake cam off by one tooth. It runs but uses too much gas. Now I understand the importance of the intake and exhaust valve timing.
experience is more valuable then reading info imo. Keep at it
Wow! That was a really good video Tony. Job well done!
Your dead on right about most people don’t pay attention much less know a whole lot about that chamber and gas flowing issue during overlap. Big power in the overlap and if the chamber is a good one, in your own words, the magic happens.
Hotdamn I love engine theory on a tuesday night.
Still need more uncle Cathy 👍👍
Great video. The problem is knowing how much overlap to use
That definitely explains the pent-roof chamber thing...They wanted the benefits of the hemi's canted-valve setup with the more-direct intake signaling, but they wanted the non-valve areas closed down as much as they can. Hadn't thought about it like that before.
Most interesting Tony. It's almost like listening to my grandfather explain the very same things years ago to me, (I'm almost 69 now). About 20 years ago I created a set of 400M heads with "squish" areas like a 460, but built for the 531/400M engines. They ended up working very well. I have a set off, and if you would like I will dig them out and take a few pics and send them to you for any sort of reference that they might be good for.
Excellent information. Really great to bring this up and mind people about the combustion chamber valve placement valves, valve sizing ports. All of that stuff. The cylinder head truly is one of the best places to make power from
Tony I'm not a mopar guy and not a chevrolet guy, but always been a fan of closed chambers, compression and cam timing with intake closing being the most important event. And testing is the only way to find the sweet spot on the cam design. I haven't bought an off the shelf camshaft for my own projects in over 30 years. Yet with all I said, I know there is much more to be learned about combustion chambers design.
Ok I'll let the cat out of the bag, I'm a lowly oldsmobile guy. I have a stock stroke .030 bore 455 that makes 625hp/640tq on the pump with a single carb single plane. Currently running a custom crane hyd roller with a standard iron distributor drive gear on the billet shaft so I didn't have to worry about bronze gears. The cam is based on LS chevrolet lobes, it's .620ish lift 255/260ish @ .050 duration on a 110 lobe sep. I know there is more power if I tweak the grind but I'm tired of juice lifters and wanna go solid roller next. Goal is 700hp normally aspirated all Olds, and I'm on my way. The info in this vid is just part of the answer but well done presentation and I hope others pick up on what you are throwing down!
Instead of doing an Edit on my own comment thought I would just throw out another one.
All this combustion chamber talk revitalizes my desire to build a custom head for the brand of my choice, which is Oldsmobile, and what I want to achieve is a canted valve, a la big block chev (the porcupine) and fit them within the space given. Reason is this cross flow theory/dynamics Tony is talking about in the video, but doing so by unshrouding the flow around the outer sides of the valves. Valve shrouding kills more power than many other things when the inherit design is a 10 degree head with the valves in the same plane. I believe a canted valve in an aftermarket aluminum rough casting cyl head for Olds may finally achieve the 400+cfm mark to make this engine more competitive. I could be wrong with this but sure hope to try it before I die.
Around 1969 Olds engineers designed a near "hemi" design based on a standard 455 short block. I'm a die hard Olds guy and forget the freaking designation they gave this engine. Maybe it was called a W-43? I don't know I gotta look it up... But they actually built a running version decked out with stock accessories of the time to actually go into production. But 1971 and emissions kinda killed it. I believe they only built 2 or 3 of them. One is on display in the GM car show trailer showing innovations and different engines the company built over the years. Far as I know there are no running examples out there in the real world as of 2022.
Thing is I wanna make a cyl head out of aftermarket aluminum to kinda achieve the same thing. I'm not gonna set the world on fire but if I can bring a new found respect for the Olds name then I'll be happy.
Great video. The primary header tube length and diameter in conjunction with the sizings of the collector create a low pressure pulse. Plus the column of hot air racing away from the exh port draws or sucks the initial incoming intake charge into the cylinder. Yes small amounts of raw fuel air are siphoned away but it kick starts the int charge moving. Add that to ram tuning the arrival of the fresh int charge pooling up behind the intake valve and you gain serious horsepower. Ram tuning both int and exh to certain rpm ranges. Extra compression almost always adds more power too across the rpm range. The gigantic amount of deep scientific variables is a key reason I love drag racing so much
I'm running a Cleveland with 2v heads and wanting to figure out how to "close" them. Wish I could afford to change over to 4v closed or , in my happy dreams , Aus 3v heads. I e thought about filling with weld but then came to my senses when I thought about the weld breaking off and trashing a rare engine! I hope UT can make those open chambers into closed and even chamber cc across the bank! Cant wait to see how its done!!!
th-cam.com/video/qEvbrybtt60/w-d-xo.html watch this to see how Bob Glidden modified those heads.
Why go threw welding and machining the heads the cost would cover just buying good heads
I'm guessing it goes along with the premise of the channel 'work with what you have '
Because there are no heads available that incorporate these features and retain the standard LA intake and exhaust patterns/hardware
Wholly cow my head is full!
No joke, your best video yet!
Hi Tony, When you mock the head chambers will you be using clay to make the best surface that you are looking to use?
Very good video, when I was in school my teacher tought us ,cam profile, overlap are your starting points ,and your video like he did explaining why. Thanks for the video.
Now I am filled with questions like "how does this then relate to you picking camshaft?" and "wouldn't a raised piston of some design be the best way to tackle the combustion chamber shrinkange or would it hurt?" or how about this being the reason behind that idea that an exhaust system promotes more of that pulling action thru the chamber, single vs dual... all kinds of questions now that this little piggy must know the answers to! haha I like these learn em videos.
a raised or domed piston (to create compression) can impede airflow into a cylinder and sometimes can block the flow of the spark--some domed pistons come with a "flame tunnel" milled into the dome.
but it is interesting how many will pick a camshaft design to help the ports flow more air by keeping the valve open longer....yet if the combustion chamber doesn't burn well enough, you're just moving raw fuel in and out. Now, if you can do a good angle grinding job on the valve seats in the head and on the back of the valve face, you can help the port flow more air/fuel at low valve lifts. which will create the effect of more overlap at the cam as the intake valve begins to open off the seat and the exhaust valve returns to the seat. so you can have less overlap in the camshaft profile if vacuum to drive power accessories was an issue.
I think I'm starting to understand the "open" vs "closed" chamber head. Can you recommend a source for further reading on this feature? Thanks
I love the idea of welding the combustion chamber! Rock on UTG! 🤩🤩🤩🤩
When I listen to you talk cars and mechanic stuff I harken back to the days when I went to school to learn the trade. Bill Pfeifer was my instructor. Real cool old school no nonsense kinda guy who could explain the whole lesson in basic words. The only difference between him and these videos is you never mention "Joe Blow's Garage down the street".
Hi Tony
Great video, I love in depth engine tuning, and have been playing with engines about 30 years now.
To be fair though David Vizard does also talk all about this stuff and is also a wealth of knowledge .
Great Video, loved it.
👍👍👍👍
David is a friend of mine, and we've done a couple of shows together. He's been under the weather lately, but I hope to do something with him again soon.
That would be gold..
You should build a magnum and push it to the breaking point to compare it to the strength of an L.A.
Welding and modifying a cast iron head combustion chamber, you know I’m going to be following this series closely.
I'm surprised you haven't done this video till now, good stuff man, really good stuff.
Very well done video brother. I think I am going to keep my 318 in my dodge shortbox pickup but I would like to learn how to port heads is there a good casting number small block Mopar head. Cuz I am going to keep my 440 727 for a 66-67 charger or a 70 superbee my dream dodges. And I want to get some power out of my small block dodge
Great video, this is definitely a variable I’ve never thought about or heard of.
HOWdy U-T-G, ...
Thanks for the EDUCATION
COOP
the WiSeNhEiMeR from Richmond, INDIANA
...
Hope next Sunday's live goes better. Definitely enjoy the sit down Q and A type video.
In your opinion how much horsepower gain can I get from reducing a 76 CC head to a 73 CC combustion chamber?
I'm confused. The Hemi design improves flow by (essentially) placing the intake valves in-line with the exhaust valves, but the lack of a quench pad hampers flow. So is it good or bad, or what?
He reminds me of my Saab mechanic whose dad was the midwest's best lotus mechanic.
I'll subscribe
Not sure if you will see this Uncle Tony but interesting enough back in Hondas glory days they used open chamber heads on there type R, B series engines. There was always a debate on what was better but my opinion was always they knew what they were doing. (Highest hp per litre N/A production engine records for 15 years until Ferrari finally beat them). I think they went open because it helped de shroud the valves. They flowed like crazy and reved in the 8-9k range . Also just as interesting spoon was running such high RPMs on the B series they had issues with pistons out accelerating the flame front. Maybe another reason for open chamber?
On an LS3 engine, does a .010 thinner head gasket only help the engine run more efficiently or does it gain hp/to. Calculations say .3 tenths compression change.
When my mentor Clif Kolostow worked at Ed Miller's in the late 60's early 70's they would take brand new 340's and mill the heads .060"
That turned the open chamber head into a closed chamber head. I think they were more interested in upping the compression, but what you are talking about here was no doubt a part of why they were doing that. One thing is for sure. Their 340's ran better than most. Like MoPar said, "340...the Big Bore Hunter"
I've learned what Uncle T is talking about over many years of going to Bonneville... As Gray Baskerville called it, The Great White Dyno. Dollar per Hp, the recycled blown fuel Hemis that guys use have the most bang for the buck. The two fastest Blown Fuel Roadsters at Bonneville are nitro powered Hemis... one is naturally aspirated on nitro and actually went faster than the blown car. The N/A gas classes are ruled by wedge type engines. Blown gas powerplants seem to do slightly better with non Hemi designs as well. One friend of ours ran a 500 inch TFX nitro fuel Hemi on 4 cylinders on one bank and the car went just as fast as the full configuration. They estimated it had to be making 500-600hp per cylinder to go the speed it did with 250cu. in (E record 303mph). Car number 125 has blown fuel competition coupe records starting at AA 305.241mph A 305.607mph B 311.149mph C 300.022mph D 296.278mph E 303.231mph Keep in mind these engines are de-tuned from a drag racing setup... they have to last up to about 80 seconds under load each pass and it takes 2 pass average to set a record. Also Bonneville is around 4000ft above sea level.
Exactly what I'm setting up to do is welding to fill in key spots of the combustion chamber for a better burn and round all sharp spots for ceramic coating and modify a dome pistons with a unique pistons shape.
I'm only truing the heads. 045 cast steal. Heads crack and fail when shaving to much for a certain combustion raio.
Filling in parts of combustion chamber cause of what IL experimenting with.
Tony
You forgot to tell your audience why and how the 5th cycle does what it does nd why -
So the Lobe Separation Angle generates the overlap event = the 5th cycle
The closer the LSA the more overlap and wider the LSA the less overlap
The squish/quench area is the most important part of all wedge heads and the optimum for that is zero clearance when the engine is running a max RPM - the problem then becomes the trapped end gasses between the piston and the head at TDC - but there is also a solution for that called the "V" Groove - With the proper amount of swirl and the v groove you can run 12 to 1 on pump gas
Hemisphereical combustion chambers, 4 valves per cylinder, and modest turbocharger is how my car makes 300 hp from 139 cubic inches. In a 3300 lb wagon, it will get 26 - 28 MPG.
OK. Now, how does the 30 degree intake valve angle used by Pontiac, and followed by Buick and AMC, play into this? The 30 degree valve seat flows from 0.030" lift instead of 0.050" lift with the standard 45 degree angle, having the effect of more cam than is actually there. Doesn't flowing sooner give the effect of just that much more overlap?
this video is pretty good but theres a few things id add, im not suprised that anyone would be lacking knowledge on this stuff becase of how sparce the info is and how hard it is to find. the hemi chamber bolth has the least serface aria for a given volume whitch helps retain heat in the combustion charge whitch ofc is responsable for the power you make and due to this it wont form hotspots adding to the spark plug point you made. the performince also has to do with the fact you can fit massive valves to the engine whitch allows large flow along with the geomitry advantage you mentioned. open combustion chabers came about becase the lack of high octane gas so they wanted to decrease surface aria and compression whitch also aids in emmisions kinda. high surface aria reduces the temp of combustion whitch does decrease nox emmisions. though the increased swirl and turbulace also helps with emmisions due to having a more homogonus and complete combustion. this also aids in high rpm performince sence you have alot less time to complete the combustion event so any added turbulince helps. though high rpm induces turbulance due to the increased flow whitch is one of the reasons why why we see hemis perform pretty well at high rpms. its always intresting to me that designs like the hemi and the rotary whitch i conciter to be on opposite sides of the spectrum due to the rotarys large surface aria per volume making combustion happen very slowly. bolth of them suffer from a large lack of turbulace.
Brilliant treatment of combustion chamber design wrt performance. Thank you ;^)
I would like to see the best la360 head next to the best la318 head. Maybe in a video as the plan comes together!