So I built a 340 in 2000 was going to do the high volume pump thing till my dad advised me being a mechanic in the 50 60 and 70s not to. His take was make sure your clearances are right and cam bearings where good am I would have any trouble with a stock oil pump. 20 years later the engine is still running 45 psi hot idle. Been into 6500rpm many times and still going. Old guys rock. Lol
@@fastinradfordable on a freshly rebuilt motor with proper clearances it is fairly normal. Most people run a 15w40 in older engines which will also increase pressure. After 20 years to see that much it is likely not a daily driver and has minimal wear.
Smokey Yunick was a fiend for reducing any unneeded oil pressure to free up horsepower, I've read he often began with the cheapest parts house oil pumps, modified them, and then used them in 100,000 dollar engines. Even Ralph Earnhardt used hardware store screwdrivers for axle keys that wouldn't break.
Facts. I remember back in the day the first engine I rebuilt, I was priming the oiling system prior to starting the engine using a drill and when it started building oil pressure the drill about twisted my adolescent arms into a pretzel because it takes A LOT of power to turn the oil pump and make oil pressure.
@@baby-sharkgto4902 I eventually bought a very heavy duty Milwawkee drill for this reason, I think it turns 850 RPM and sports 3/4HP, got this covered now, lol. ;)
He was saying in the video with the tunnel ram that it actually improved gas mileage when set up right. I think its because the extra time the fuel has to atomize
I've been hearing the 7psi per 1,000 RPM rule of thumb forever but no one could explain what the forces were that determined that. The centrifugal forces explanation seems obvious now that you explain it. Thanks Tony. I just learned something valuable
Great info as always. A quick note for my modern engine guys: Remember that these new generation engines are engineered differently designed with different expectations of idle PSI. Hydraulic tensioners do not like 7PSI, and any flavor of Hydraulic Valve timing (Found in basically every new-age engine) is designed around the engine producing closer for 30-40psi. TL;DR, Don't expect your 2020 Focus to like 7PSI idle oil pressure.
I owned an MGB once upon a time that had approximately 40 psi at cold idle. When i revved the engine the oil pressure dropped. after a short warmup the pressure at idle barely registered and disappeared entirely when revved. a complete teardown revealed nothing obvious. i was examining the oil pump when i dropped it on tbe floor and got a bit of unseen dirt in it. i stuck the driven rotor back in and absentmindedly twisted the shaft. the rotor didn't turn, the shaft did. turned out that the pin securing the driven shaft had sheared . when cold there was enough friction on the shaft from the sheared pin to generate some pressure but revving would make everything slip.
I thought the rule of thumb was 10psi/1000rpm, but not a huge difference. BTW, the tangs on the bearing shells are not there to resist rotation of the shells in the rod/cap/main bore. They are there simply to align things during assembly. Some newer engines don't even have the tanks. Bearing crush is what keeps the bearing from spinning in the bearing bore. I've seen several BMW S62 rod bearings that went metal to metal. What happened was that the tangs ripped off the shell and the bearing rotated a bit. Those pieces of tang then gouged the bearing and rod journal (since the backing is steel). It would have been better to not have the tangs there. I replaced the bearings with King bearings, which have more crush and more eccentricity, along with ARP 2000 rod bolts to stave of spinning the bearings.
10 psi per 1000 is what Smokey wrote in his book "Power Secrets". He also said in there a 350 would survive as low as 55 psi, but not to let it get lower
I never knew this Uncle Tony. I always thought high volume oil pump would be best but, you just educated me on this. You also educated me that sometimes more is not better. It pays to get other opinions and sometimes just listen and not have blinders on. Thank you Uncle Tony. I really appreciate your experience and the time you put into your videos!!! 👍👍
@@AmosMosesJr No it's really not; a higher volume pump with the same engine clearances means you are still wasting power and heating up the oil pumping more of it through the pressure relief valve. You only need a high volume pump on an engine that is internally very leaky, with respect to the oiling system. That is not the case for most engines as UT says in the video.
@@redmondjp my point is a high volume pump is not going to have nearly as much parasitic loss as a high pressure pump. All depends on the application. I've worked on more industrial engines and don't race. I suppose if you're working on a smaller engine it might matter. I have seen hydraulic systems with too high of flow pump that overheated the fluid being pumped. It ultimately melted the sight glasses off the reservoir. That's a whole different issue that should never happen with an oil pump.
@@AmosMosesJr You are not understanding my point. The pump does not work alone. If you do nothing else to the oil system but increase the pump flow, the system pressure will increase and you will heat up the oil blowing it through the relief valve just as you described.
@@redmondjp I suppose you're right. Wish we had real numbers to compare in regard to parasitic losses. I still suspect that higher pressure would play a bigger factor more than volume. I used to play around with vw beetles back in high school and I read that those had no oil filter to save on hp loss. But those only put out 25 to 60 hp.
This is awesome Tony, oil pressure and it's relationship to cooling the rod bearings is one of the most overlooked items that racers and race engine builders miss.Pressure is just the resistance to flow, increased clearances reduce pressure, but that's only part of the story, what a lot of builders don't quite get. I've found you can have great oil pressure and still burn up rod bearings, been there and done that. What I needed was increased oil volume flowing over the journals, to keep the bearing shells cool. Fail keeping them cool, and the plating on the bearings blisters, separates from the steel bearing substrate, like chrome plating bubbling up on an old bumper. The infamous 'glitter in the oil'. Once that happens, it's game over, the bearings need to be replaced pronto, otherwise the plating sluffs off, down to the steel core, and micro-welding takes place, bearing spins, crying and long faces, and a long tow home..
The rest of the video is pretty informative I just got to make one adjustment. note the tangs of a bearing are not to hold it from spinning the tangs are only a reference point to locate the bearing.. what holds the bearing in place is the "crush" how much the Rod Cap and the connecting rod crush the bearing in. the friction on back of the shells is what keeps the bearing from spinning. I'm not trying to take anything away from you Tony🤗 I just wanted to relate that to other people. 🤗 I think you did that to see if we're paying attention 👍🤗
Solid advice as usual UT 💪🏻 Such a common mistake here in Australia on the old Holden V8 engines. People will put a high volume pump on a very mild engine and just end up filling the rockers full of oil and not allowing enough time for it to drain back. Appropriate mods / oiling system work it can be done, but so many combos its not even applicable. Worst one I saw was sustained high-ish rpm (drag race) with a high vol pump which starved the bottom end and spun a bearing or two.
I've always heard a minimum of 7 psi/1000 rpm too so I always assumed that was ok. The only time I've ever used a high pressure pump is on race only engines. High volume pumps can actually damage an engine if you run a stock oil pan. There's a chance that they can empty the sump and starve the pickup before enough oil has drained back down. I do disassemble the pump (new or used) and check the clearances as well as making sure that the mating surfaces are flat when I do any build.
Not true in all cases. I'm using a hv pump with my stock 402 pan in a freshly rebuilt 440 and never had any starvation/pressure loss issues no matter what rpm it's running. Yes, if you're low on oil or have restricted passages there's the potential for aeration, but try suspending over a gallon of hot oil in mid air.
With the 4.6 modular if you have 4v heads, you have to have a HV oil pump, which came factory on 4v applications, but it's because you have to properly oil all 4 cams and give pressure to all 32 lash adjusters.
Tony's explanations are excellent!!! Especially when addressing things like this... Just the knowledge, of the effects of proper bearing clearance and the direct corellation of oil pressure and the condition of the bearings is good to know!!!
My 408 Cleveland hydraulic lifter setup has 2thou clearances throughout, it runs a Mellings hv pump using Brad Penn 20/50 and it achieves around 50 pounds at idle (warm) peaking at around 80 pounds at 6000rpm. It was built with a mild street aim with lower maintenance in mind. It runs most of the internal goodies with 245cfm rated 2V closed chamber heads limiting a couple of factors, home built 14yrs ago, on the dyno it made 250rwkw and still runs just the same today as I've only put around 14k miles on it since the build and it is maintained religiously. Your not wrong about parasitic loss though, it can quickly add up all over the place. It runs a large 7 blade fan surrounded with a good quality shroud, 1 big loss right there but I KNOW it's always doing its job, I carry a spare belt atleast. It's all horses for courses I guess, and what fits the budget at times. Great video once again Tony 🇦🇺👍
@@kramnull8962 Remac Performance here in Australia did the rotating assembly balance and line hone bored the camshaft/crank journals. I'm unsure personally of where the meat is missing, it was along time ago now. If it dawns on me I'll be sure to reply 👍
Amazing presentation once again. Uncle Tony speaks off the top of his head, with the detail and sequence of a thoroughly organized engineering editorial. Must be all that writing experience! Thanks UT!
Good of you to bring to light this oil pressure issue. This is something I also learned many moons ago, how parasitic losses both absorb power otherwise available for performance and decrease fuel mileage in the same manner. This type of thing was a big part of what went into my customers engines. The OEMs have only begun to take the parasitic oil pumping losses to the next level as of late. Several manufacturers before, and now Chevy's C8 Corvette have ECM modulated oil pressure, the bypass used to reduce oil pressure to the much lower level required at a lightly loaded cruise condition, and then ramp it up under high load conditions. And some say hot rodding doesn't contribute to improving production cars - I say bullshit.
I hate when I ask someone why they do something and all they can say is "well it's just what you do" or "this is just how I've always done it and it works fine". I'm not a hot rodder or even really a "tuner" (I just found this channel because I got an 88 Jeep YJ with an Edelbrock carb - first time dealing with a carburetor and was looking for videos about getting it set right) but still found this video hugely enlightening...the bit about how roller bearings will skid on oil reminded me of another video I had watched about how bowling lanes are pretty finely tuned by how much and what kind of oil is put on them and led to an "ohhhh so THAT'S how those things work" moment. I would LOVE to see more videos on topics like this that really dig into exactly WHY certain values are what they are...why do we run thermostats of a certain value? Why do we set spark timing where we do? What changes when we modify these values?
Thank you for backing up what I have been saying for years. Also, getting the oil to flow through the motor is cool. Ask anyone who has built a Cleveland.
I had a good 1970 360 F.E. with 20 p.s.i. and wanted to bump it up. I added a full qt. of Lucas oil stabilizer and got 80 p. s.i. WAY too much! Drained it and put a Pint of Lucas in and got 40 p.s.i. @5000 rpm. It was much happier and so was I!
There are two factors used for calculating horsepower requirements for pumps, flow and pressure . reduce either one and there is a reduction in required HP. Great video Tony.
Always great info! I've messed with oil pressures and oil viscosity for years and ruined a motor or 2 by bad thinking. Best advice is to stay as close to stock as possible if using stock specs on rotating assembly. On an old engine with low oil pressure a high volume oil pump may buy you a few more years. I used 50 w in an old engine thinking it would provide more cushion on my rods and ended up starving front 2 rods! So oil viscosity and not knowing what your doing can have dire consequences
Thanks for breaking it down. I knew higher oil pressure cost horsepower, but I didn’t know the bottom line for running low oil pressure safely. Great job explaining 👍
I'm so happy he got it right concerning oil pressure. So many places wrongly advise high oil pressure is a goal. Not just cars but many heavy duty truck engines also run with low oil pressure from the factory. My International 392 cu in engine has been running less than 10 psi at idle for more than 40 years and I don't baby that work truck.
We learned that lesson back in the early eights. Playing with circle track cars, one year we say we were not going to have time to finish a new car and a new engine. A friend racing ARCA recommended a builder to us and we had a engine built. On delivery the parts list shown a stock mopar oil pump. When questioned his response was try it you will like it. He then ask about any problems in the past with engines. The only thing we ever had was a couple bearing failures. At that point he responded that we must have been running a high-volume oil pump and yes, we had been. He then informed us all were doing was overheating the oil and pumping it all to the top of the engine at which point the oil pump sucked air and the pressure drops to oh shit levels.
So glad you brought up the loose builds and more flow = more heat leaves the journal and less resistance to flow takes a load off the system.. The primary purposes for lubrication is lubrication and includes cooling. I love the oil wedge comments and how the oil enters the journal- it's why the oil holes in the shafts within the journals are located where they are. To maintain the oil wedge, where it feeds into the journal plays into the place where the journal is put under load- the compression stroke and is to cushion the journal as it loads. I hear other rebuild guys talking about journal radius and side clearances. This does play into how well the oil will flow through the bearing- too much clearance will result in an oil pressure drop in the system and the oil viscosity previously run with a different clearance won't provide a familiar result. When refitting old Dodge crank journals with fresh shells, what advice can you offer for appropriate clearance? Not just what the plastigage says, but side clearance. What kind of journal side radius should I check for on a rejuvenated shaft journal and should I be chamfering the shells? I realize that loose is good, but to much of a good thing can be bad, too. Thx in advance.
my 1974 kawi G5 100cc 2 smoker actually "pressure" lubes the crank mains . half goes just past the carb..... the other half drips on the mains OVERKILL for a 100cc smoker that makes 12hp.... . but, ive put 15,000 miles on the rebuild.... and i havent had a break down havent even fouled a spark plug.... (but have replaced it when it wore out) . still starts first kick.... runs SUPER crisp.... throttle response is so good, really easy to rev match shifts up and down . . i just LOVE that bike
Thanks for clearing this up. Guys on the forums are claiming 45 psi warm curb idle. I'm new to this and was thinking I had low oil pressure. The mopar shop manuals say minimum oil psi for 318, 340, and 360 is 8 psi.
Because oil likes to cling to itself and metal the faster a shaft turns inside a bearing the more oil it will pull into the bearing, yea it draws itself in. There are some of the new design engines that need some of that pressure to spray sufficient oil out piston cooling jets and maintain pressure on cam chain tensioners but even then it's not an excessive amount. I remember back in the 80's, Cummins changed there strategy on the 855 diesel in over the road trucks. They went from typical 65 to 75 PIS oil pressure to 40 Psi. Reduced oil shear, and parasitic load a lot. Mainly freaked out experienced drivers but it really worked. We had a small Detroit engine in a truck that at overhaul it got the incorrect spring in bypass. It had about 15 PSI more pressure than it was supposed to. After about 15 to 20 miles running down the road it would develop low oil pressure. Seems the excess pressure caused the oil to get hot from shear then it would be to thin, changed spring to reduce pressure and pressure drop went away. Love your stuff Tony and I'm not even a Mopar fan. Keep up the good work.
Good tips! As a very general rule of thumb if no specs specific to your engine are available, I agree that 7-10 PSI of oil pressure per 1K RPM is typically plenty. The only issue I have with this advice is the suggestion to use a thinner than specified oil to reduce oil pressure. Even if the bearings might be alright, the pistons, rings, cylinders, camshaft, lifters, pushrods, rocker arms, timing chain, etc don't know or care what the oil pressure is and may not like a thinner oil. As the SAE viscosity grade drops, the HTHS viscosity typically drops too. A quick Google search for "hths wear graph" shows why that could be problematic if taken too far.
I found and restored an antique Soviet Union KMZ Dnepr military sidecar motorcycle. You can call it the step brother of Ural sidecar motorcycles. It's oil pressure is 6 bar or 86 psi. While I was reading the manual I found the reason it's so high. It's for cooling and lubricating the Pistons because it's designed to operate at idle for extended periods of time. It's an air cooled boxer engine so you would think idling like that at 5km an hour would burn it up. The way it works is high pressure and volume oil is pumped to the crankshaft where it lubricates shell type bearings on the rods but then it sprays out of the bearings and into the back of the Pistons. It also produces a thick mist of oil that lubricants the ball bearings on the crankshaft and camshaft. That slinging oil also lubricates the cam lobes and lifters. Small channels guide oil down the pushrod tube's to lubricate the rocker arms and other valve components. The heads and cylinders have deep cooling fins as well. What's even more interesting is Harley Davidson made 1,000 copy's of them in 1942 and 43 calling them XA models for experimental. They were going to be used in North Africa but by the time the XA's we're finished testing North Africa was won and done.
Again, You are bang on Tony. I grew up with the old - and I mean "old" school mechanics who had dirt floors in there shops and nicotine and oil / varsol permanently stained fingers. But man O man, did they know how to make mechanical things work and work better than stock in a lot of cases. I wish I could have absorbed more of their wisdom and knowledge but I retained as much as I could, and that knowledge has given me a great base to be able to work on or "hot rod" the modern engines as well. Love your channel and you knowledge man 👍 I would happily push a broom around your shop and even clean the toilets just to be able to be around you when you're thinking out loud. PS; I'm 60 years old, so it ain't no spring chicken doin the talk'n here.
Well your video might be a year old but it certainly answers a lot of questions that I have wondered about for more than 50 years! In the 70's I used to build high revving high hp straight 6's. They often hit 8k Rpm I never went to route of high volume high pressure oil pumps cos I just didn't see the need. That's not to say I really understood, I just chose not to. Who would have guessed.
Tony, Tim Arnott here, GREAT vid!!...and you are correct sir!!...my Pontiac has the RAIV Pump/pickup, usually described as high vol/pres.......it makes about 585 hp......i use a 10-40 wt cuz 20-50 wud create to much pres.....warm, at idle, i got 25psi........as soon as i get to 2500 rpm, i got 75 psi, all the way up to 6200 rpm......thats plenty......my brother wanted me to use 20-50, but i knew that was to thick, and to much parasitic loss, with no lubricity gain.......it runs fine, and 11:07 ET at 120 mph at the track satisfies me nicely.......GREAT VID!!
I DID get something out of this,Uncle Tony!I always thought you needed high oil pressure.This falls under the category of "less is more". This is good to know!
One of the top misunderstood engine rebuild topics! I think I read about this in a Hotrod magazine once back in the 80's. Glad you addressed it here again.
Thank you for crediting Bill Jenkins and especially (my hero!) Smokey Yunick. Over the years Yunick in his HP series books and contributions to Circle Track Racing magazine has enlightened many on the basic principles and physics of engines and related ancillary systems resolving the many unfounded 'myths' that have been around much too long. Keep in mind he 'schooled' the GM engineers more than once proving what actually happens inside motors vs the misconceptions they held for decades. Don't forget the number of times he outsmarted the NASCAR tech inspectors, some of which is legend. He did the same moving to Indy then later to Trans Am. A genius, always looking for answers that most never considered.
I remember my dad had a truck that when it was hot the oil pressure went to 0. Ran well. The real bearing ability comes from hydrodynamic pressure. This is from the “ wedge” that is built from spinning parts. That hydrodynamic pressure is from the lubricant not the oil pump. If you do the math 50 psi will not stop engine wear if there is no hydrostatic pressure.
I have a 1964 Galaxie 500 with the 352 FE motor. When I rebuilt the motor 30 years ago the rebuilder said to use 10w 40 as a break in then 20w 50. He has retired and closed up shop. I talked to another mechanic and he also said to use 20w 50. Although the owners manual from 1964 says to use 10w 30. I use the 20w 50 but change it every year even if I only put 500 miles on the car. I also add 1/2 qut of marvel mystery oil.
My old 55 Studebaker 259 idles at 10 psi hot , I did a lot of clearance work to the oil pump and bearings too . Always thought that was low , but it is the way the engineers designed it . Thank you Tony , another Tony from Hemet , CA.
A Studebaker v8's pressure regulator is to the timing gear teeth, not at the pump. I run near 40psi all the time using 15w40 CC/CD type oils. Do you have the restrictor in line with your oil filter? otherwise you have more clearance than you should. Are you still using the floating oil pick up, and is its pivot not sucking air. If you are using a C4 oil filter, are you carrying your oil higher than the stick, or check the level before the filter drains back to the pan? I inverted the P-50 style filter on a few so the filter is always full. The oil relief valve is what oils the teeth on the timing gear. As a C4 style fills, the level in the pan drops. If using a 56 or newer pan, you are already short a quart. Last oil pump I did involved a little lapping to keep the plate close to the gears. Lastly how was your cam bearings? have fun
This was helpful my 5.7 goes down to 7-10 at idle so I idled it up some. My last van was doing that and on a hot day in summer at a stop light it went to zero or close. Put in an oil pump and it had a knock so installed rod and main bearings while in the van and it spun a bearing after about a year of light use. I hope this van doesn’t do that. 2001 GMC Savana 3500 145,000 miles.
My tired old 350 Buick motor when hot, idles around 10psi and runs 30psi when cruising down the hiway. No knocks. No ticks. And in my 66 Chevy truck with a 3.08 gear and a quadrajet, I can squeak out 17mpg on the hiway. 15.5 if I cruise around 70-80.
Maybe not the safest thing to do, but running 1qt low can keep your crank from dragging through the oil and free up horsepower as well. I run an 8qt pan on my Small Block Olds and only run 7 quarts, no need for fancy windage trays and reduces the parasitic drag.
👍 in the past I never gave or oil pressure of thought Beyond making sure I had "normal pressure". Then I started building VW type 1 air cooled engines for my airplanes. Fortunately at the local engine machine shop the gentleman informed me of the dangers of too much volume when I said I was going to go with a high-flow oil pump. He advised against it stating cooling issues. That plus it has no gear reduction too the prop. Just straight flywheel Drive. 3200 RPMs Max. Cam makes its power between 1,200 and 3,000 rpm. Approximately 160.hp
Thanks for your video I was told my 396 at hot idle was to low between 15-20 when you step on on the gas it raises up to 30-35 at 185-190° cold idle is 50-55. I was considering a high volume oil pump burning after your video I feel much better about it. Thank you. 👊👍
I'm so glad we have tony he has helped me tremendously it's so hard to find good no bullshit information I bought a high volume for my 408 I put in my pickup because everyone tells you to but what your saying makes complete sense I'll use thinner oil to compensate for now lol
243K miles SBC with condensation in the oil. 5lbs Oil Pressure at warm idle. Wore out? Wrong. Factory Dash gauge was wrong. PVC valve at TBI clogged. Installed manual gauge = 20lbs at warm idle. Cleared PVC system= no water in oil pan. Sometimes its the little problems. Rebuilt the Motor then found the real problems. Completely clogged PVC tube in TBI unit was missed by 3 mechanics.
The roller bearing bottom end of your Sportster is pressure fed, as were the rod bearings of the Big Twin V-Twins from that era. The “full flow” roller bearing bottom end on Big Twin machines from ‘73 though the last EVO, stopped pressurized oil to the connecting rods below 12 psi at idle to maintain adequate pressure for the hydraulic lifters; Ironhead Sportsters prior to ‘86 all had solid lifters. The pressure relief valve in the pump would open the passage to the connecting rod roller bearings at 12 psi. This is why at operating temp you would not see an oil pressure rise above 12 psi on a stock machine.
Tony: Thanks for the insight into oil pressure and it's causes. Any information about oil pumps, especially SBC oil pumps, is greatly appreciated as well. The reason for this is that I can't find a great deal of information about oil pumps with the cause and effect situations in my studies. Again, you help is well taken seriously.
I use to sit in smokey yunick office when my old man use to talk to him. U were a big help I have a 300 6 banger at idle is has about 7 psi it has 210000 on it
I have an early HD Panhead and the service manual reads oil pressure 35psi, 20 psi at 20 MPH. It is adjustable. Timing case gears are bushed. The main shaft is roller bearings which are "air cooled". The rod big end is roller bearings that are oil cooled. The rods fling oil all over and need good pressure/flow to not over heat. Thinner oil does ccol better.
years ago, I had a friend who was running a "TRANS AM" at the drag strip. he was always breaking the oil pump shaft tangs off at the distributor, and loosing engines. I asked him what the oil pressure was, he said "I DO NOT KNOW--- IT IS PEGGING THE GAUGE" ( over 100 psi) I told him "THE MOST OIL PRESSURE YOU NEED IS 40 PSI, YOU ARE NOT RUNNING A DUMP TRUCK" he changed the oil pressure relief spring in the pump and got the oil pressure down to 35 psi( when making a pass) he thanked me for the fact he went from a 12 second machine to a 9 second machine, and did not loose any more engines!!!!, you are "SPOT ON" when it comes to oil pressure, I remember the 472/500 cubic inch cadillack engines that were set up with 20 psi oil pressure from the factory and never had any problems. the auto industry had federal mandates that had to be met by a certain date, when it came to fuel consumption, they did it by running ultra light weight oils without modifying a thing on the cars/ trucks that they were producing!!!!
In my fiat punto 188, the manual says at list 0,7 bar at idle and at list 4 bar at 4000 rpm, just saying. Also a lot of truth in this video!!! keep it up!!
oil pressure and recommended oil types is the most misunderstood thing in shade tree mechanics. i know people that run extremely high viscosity oil in their daily drivers just because that's what pro-mods run, so it has to be the best oil, lol. everyone knows someone that knows someone, so that's why they run oil completely different than what the manufacturing engineers specified for their vehicle from the factory. just run the weight that's in the operators manual. if you have low oil pressure then something needs repaired. running extremely thick oil just to increase the pressure may cause wear if the oil is too thick to flow into the actual clearances. uncle tony just put out a great video and clarifies a lot. bottom line- research before choosing an oil if you have a custom build. you should know the targeted clearances before you ever build an engine. the oil you need is based on the clearances you have. using the wrong oil will cause premature death to any engine.
Tony, here's another trick to reduce parasitic losses, and Mopar-specific: The first CAST crank big blocks had a weighted balancer, with EXTRA weight on one side. LATE 70's cast crank big blocks weighted the balancer by REMOVING metal from the OPPOSITE side. The difference is probably 1 pound, a lot of weight at 5500 rpm. I've never heard you mention that.
I have shown people about this with our dirt late model dry sump pump. It has an adjustment screw. When your idling at 900 rpm with 50psi oil pressure and you turn the psi down to 10psi and your rpm goes to 1200 with no carb adjustment they see the light real quick. We run .0025 to .003 for our rods and mains we run restricted oil passages to the lifters because they are solid rollers...
We ran circle track dirt posse car back in the late 80s. 383 mopar 30 over 10.5:1 popup TRW pistons, 8 bolt truck crank, aluminum flywheel on methanol. Holley alcohol carb 830CFM. Solid lifter with adjustable rockers, edelbrok torqer manifold, 1 7/8" headers with spiral wound half muflers. To the point, we ran loose clearances with a high pressure, high volume oil pump and Valvoline racing 50 WT oil. We'd see 60PSI idoling and a bit higher hot at 6,800 RPM. It had a grunt sound like it was trying to shotput the car down the straights. Good times.
Tony I'd love to see you do a piece on oil pressure vs. Oil volume and how misleading oil pressure can be. For example a high oil pressure reading can actually be an obstruction while the engine is actually starving for oil. And on the other hand a lot of oil can be flowing, lubricating everything in the engine without really registering a lot of oil pressure.
Some modern cars have a variable displacement oil pump for saving fuel. The ECU will command a valve to reduce oil pressure. I used to have a VR6 VW where the oil pressure relief valve had failed. On a cold start the pressure would go so high it would overpump the lifters and make the engine misfire!
Man, I've been wondering about oil-pressure ever since I did my last rebuild because I added eight wrist-pin oilers plus one for the timing chain; and even though I used a Melling HV "SharkFin" with a washer in it, my pressure warmed up at idle was still less than the 20 psi I was accustomed to seeing. That kinda freaked me out; but on the other hand I didn't really see anything I could do about it without another engine pull and I consoled myself that it was less drag on the sacrificial distributor drive that would all too often let me know it was done by retarding my timing. I'm running a polymer one now with the hope it will outlast the bronze ones; and I think it already has. I was relatively sure this was a case where less was more; but I certainly appreciate the affirmation you've given because it does give me more peace of mind. I've been turning wrenches for 47 years now; and yet there's always something new to learn and now days, MF-ers are just going off the chain with their CNC billet blocks,carbon-fiber rods, mirror image turbos, and dual OHCs. Everybody is making more than they can put to the ground on a last chance power-glide for numbers. LOL I'm just an old street-freak trying to keep the 2.0 L turbo crowd off my ass. Still fun S though ain't it man? Thanks for sharing.
Most of us already know this but I just purchased a pinned distributor shaft right from Mopar performance. It's amazing they relied on a press fit gear.
I have a 455 olds in my rv, it's low rpm, all the guys that know suggest a high volume pump. Currently on my old 110 000 mile motor I've been using heavy oil 20 50 Lucas with zinc. At idle hot it will be at 11 lbs. If I'm using a 10 30 oil, I'll have less than 5 lbs hot . The manual says straight 30 w for 1976 . My current motor is getting tired I think, compression is 150 lbs across all. One of the gurus on this motor told me not to look at the idle oil pressure at all and run synthetic for the cooling, and to run a thin oil so that it would return to the oil pan quicker.
Interesting. I've always been told and followed for hot pressures. 5 psi per 1000 rpm for lower rpm, lower compression motor (less than 8.5:1). 10 psi per 1000 rpm for average rpm average compression, 6to 6.5K rpm up to 11:1 compression. 15psi per 1000 rpm for engines with power adders. Drop pressures 1-2.5 psi per 1000 rpm if the engine is priority main oiled.
I love all these tips....this one I new not because I am a great mechanic but because I have a memory like an elephant. Its also common sense. At some point in going to build my very first 383 stroker for my square body suburban. People swear I won't be able to get fuel economy out of it but I'm doing enouph research first I will prove em wrong! I wish I lived close, I was like your favorite nephew and you wanted to give me advice on my build......Lol
While I have [relatively] high oil pressure on start-up [50 psi], soon after warmup, the pressure drops down to about 25 psi, and will only go up as the RPMs climb up near the top. While I did nothing to this engine [internally], this is an International Harvester 392 I/C and it seems to self regulate and keep its psi at the right pressure per RPM.
Hi Tony, I'm new to your channel. This video is what ive been looking for. I just finished building my 2005 5.7 hemi with the eagle heads from a 2017 5.7. I installed a MELLING high volume pump thinking the obvious, more oil, more lubrication, more fun. The psi at cold stay would be 40-45, and dropped to like 30 when hot. But I noticed the oil light came on after driving like 20 min, and then it would shut off on me, and it would not wanna start, sorta like limp mode. Psi wouid go down to 15, but i thought that was not normal. I basically have a "stock" rebuild but, after seeing your video, I think ill have to put in a new stock oil pump. Engine barely has 45 miles after being rebuilt.
7 for ever. G I ALWAYS WENT WITH 5 FOR EVER G that was as low as I thought I could go with sticking metal together. I usually have more but the 5 has been in my head since the 70s why? I don't know probably read it one of those silly California car magazines. You live and learn. These was a good video thanks.
Really good, and not talked about much. Remember talking to the Craftsman Series Truck Racers/Drivers in the pits, and I asked about the breathers on their crankcases and a few of them went to explain that they were playing an oil pressure game at (I think) they said @ 8500RPMS; the take away for me at least in this capacity seemed to be less is more.
I don't know for a fact , but oil pressure is also based off journal diameters as well. Small journals need less oil pressure than large journals. Not sure how many, but newer cars are controlling the oil pressure , so it only gets what it needs for MPG . Another thing to touch on with high volume oil pumps is with out added capacity you might pump all the oil up top, run the sump dry and blow up the engine. All engines are different as far as that goes. Olds Engines would do that for sure, and when I bought some parts from Mondello decades back , they pretty much said do what ever it takes to get a larger supply of oil if running a high volume oil pump.
one thing I know, I need more than 0 psi at idle, and more than 5 at 1500 rpm. so I swapped the stock pump for a high volume pump and now I get 5 at idle and 10 to 15 driving around. stock german 2.8 v6 from a 78 mustang in a 77 pinto wagon.
I watched a test where a high volume oil pump only took 5 peak hp from a sbf on the dyno! That being said I ran a HV pump on a well built stroked 8.2 deck ford (302) Would see 7000 Rs on a regular basis , mechanical cam , good heads etc. 3350 mustang ran 10.80s n/a After about 5000 miles I noticed oil pressure was lower than normal..25 psi hot idle when normally it was about 40 hot idle. No noises , ran good etc…parked the car and took the motor apart that winter…..bearings looked absolutely beautiful (in fact I reused them on an old truck motor I was limping a long) …long story short the block had cracked up the front of a main journal into an oil galley…. All the wearable parts in the motor looked great……I’m sold on more oil pressure than needed …. To be fair I ran a 10w-30 all summer too and bearings clearances we’re nominal @ .003 So oil was a little thinner with a high volume pump….work good for me.
Engine masters just did a test on this. The oil pump takes almost zero hp to turn but the point is the same. Alot of times if you don't need the extra volume a high volume pump will fill the heads with oil and not able to drain down enough and starve the bottom end
I really need to get an oil pressure gauge for my 96 Buick LT1. I had a quart a day rear main seal leak. So when I pulled the engine to change the seal, I put in a Melling high volume oil pump. I figured a 25 year old engine with 150k miles might need more flow. Looks like I should've done more research. But I've been driving it for over a year like that so I guess it didn't hurt too much. Not that I can tell anyway. I definitely need a gauge though. I'm really curious about how much pressure it actually has.
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So I built a 340 in 2000 was going to do the high volume pump thing till my dad advised me being a mechanic in the 50 60 and 70s not to. His take was make sure your clearances are right and cam bearings where good am I would have any trouble with a stock oil pump. 20 years later the engine is still running 45 psi hot idle. Been into 6500rpm many times and still going. Old guys rock. Lol
Sounds like she's happy as mate. Some high zinc oil will also help it alot generally speaking
Rebuilt my 77 AMC 360 a year ago, original pump gears, i didnt replace anything in the pump. Its got 50 psi at idle
45 psi is very high for warm idle
Wayyy higher than necessary
@@fastinradfordable not really
@@fastinradfordable on a freshly rebuilt motor with proper clearances it is fairly normal. Most people run a 15w40 in older engines which will also increase pressure. After 20 years to see that much it is likely not a daily driver and has minimal wear.
Smokey Yunick was a fiend for reducing any unneeded oil pressure to free up horsepower, I've read he often began with the cheapest parts house oil pumps, modified them, and then used them in 100,000 dollar engines. Even Ralph Earnhardt used hardware store screwdrivers for axle keys that wouldn't break.
smokey was a hero of mine. loved reading his column in circle track magazine
Facts. I remember back in the day the first engine I rebuilt, I was priming the oiling system prior to starting the engine using a drill and when it started building oil pressure the drill about twisted my adolescent arms into a pretzel because it takes A LOT of power to turn the oil pump and make oil pressure.
It'll put a hurt on your drill if not careful! I've heated up numerous drill motors this way...Don't burn up your drill! ;)
Yup, I jammed my hand between the drill handle and firewall while priming my 327 engine after a rebuild
@@thisisyourcaptainspeaking2259 you are right, it is very hard on a drill
@@superrodder2002 haha I could see that happening
@@baby-sharkgto4902 I eventually bought a very heavy duty Milwawkee drill for this reason, I think it turns 850 RPM and sports 3/4HP, got this covered now, lol. ;)
I love the fact we are getting lessons on better gas mileage whilst a tunnel rammed big block resides in back ground! 😉🤩🖕
LMAO!!
WISEACRE😉
But don't cha just love that? Long live the monsters....
My high school auto shop teacher (who built drag boats) said "we teach high performance because it is also a way to understand efficiency"
He was saying in the video with the tunnel ram that it actually improved gas mileage when set up right. I think its because the extra time the fuel has to atomize
I've been hearing the 7psi per 1,000 RPM rule of thumb forever but no one could explain what the forces were that determined that. The centrifugal forces explanation seems obvious now that you explain it. Thanks Tony. I just learned something valuable
YEAH , he also mentioned the jackhammer effects of the combustion squeezing the oil film out at tdc.
Great info as always.
A quick note for my modern engine guys: Remember that these new generation engines are engineered differently designed with different expectations of idle PSI. Hydraulic tensioners do not like 7PSI, and any flavor of Hydraulic Valve timing (Found in basically every new-age engine) is designed around the engine producing closer for 30-40psi.
TL;DR, Don't expect your 2020 Focus to like 7PSI idle oil pressure.
(laughs in VW 1.5 diesel from the 70s with 100psi at idle on a cold start) 😂
at some point a lot of the old school engine building rules stopped applying to new production stuff
@@andrewgarcia3136 yep,
New machining techniques that give tighter tolerances plays a role in this.
Does the 2020 focus have a variable displacement oil pump? These are becoming common on modern engines.
@@fatasdat yep, same way you can't run 70 weight in a coyote safely.
I owned an MGB once upon a time that had approximately 40 psi at cold idle. When i revved the engine the oil pressure dropped. after a short warmup the pressure at idle barely registered and disappeared entirely when revved. a complete teardown revealed nothing obvious. i was examining the oil pump when i dropped it on tbe floor and got a bit of unseen dirt in it. i stuck the driven rotor back in and absentmindedly twisted the shaft. the rotor didn't turn, the shaft did. turned out that the pin securing the driven shaft had sheared . when cold there was enough friction on the shaft from the sheared pin to generate some pressure but revving would make everything slip.
I thought the rule of thumb was 10psi/1000rpm, but not a huge difference.
BTW, the tangs on the bearing shells are not there to resist rotation of the shells in the rod/cap/main bore. They are there simply to align things during assembly. Some newer engines don't even have the tanks. Bearing crush is what keeps the bearing from spinning in the bearing bore. I've seen several BMW S62 rod bearings that went metal to metal. What happened was that the tangs ripped off the shell and the bearing rotated a bit. Those pieces of tang then gouged the bearing and rod journal (since the backing is steel). It would have been better to not have the tangs there. I replaced the bearings with King bearings, which have more crush and more eccentricity, along with ARP 2000 rod bolts to stave of spinning the bearings.
10 psi per 1000 is what Smokey wrote in his book "Power Secrets". He also said in there a 350 would survive as low as 55 psi, but not to let it get lower
I had a bearing crush on a girl once, but she said it was overbearing, I'm just glad she never ripped my tangs off.
@@damonthomas8955 LOL DID YOU MEAN TAINT OR THANG ?
I never knew this Uncle Tony. I always thought high volume oil pump would be best but, you just educated me on this. You also educated me that sometimes more is not better. It pays to get other opinions and sometimes just listen and not have blinders on. Thank you Uncle Tony. I really appreciate your experience and the time you put into your videos!!! 👍👍
Higher volume low/stock pressure is still good.
@@AmosMosesJr No it's really not; a higher volume pump with the same engine clearances means you are still wasting power and heating up the oil pumping more of it through the pressure relief valve. You only need a high volume pump on an engine that is internally very leaky, with respect to the oiling system. That is not the case for most engines as UT says in the video.
@@redmondjp my point is a high volume pump is not going to have nearly as much parasitic loss as a high pressure pump. All depends on the application. I've worked on more industrial engines and don't race. I suppose if you're working on a smaller engine it might matter.
I have seen hydraulic systems with too high of flow pump that overheated the fluid being pumped. It ultimately melted the sight glasses off the reservoir. That's a whole different issue that should never happen with an oil pump.
@@AmosMosesJr You are not understanding my point. The pump does not work alone. If you do nothing else to the oil system but increase the pump flow, the system pressure will increase and you will heat up the oil blowing it through the relief valve just as you described.
@@redmondjp I suppose you're right. Wish we had real numbers to compare in regard to parasitic losses. I still suspect that higher pressure would play a bigger factor more than volume. I used to play around with vw beetles back in high school and I read that those had no oil filter to save on hp loss. But those only put out 25 to 60 hp.
This is awesome Tony, oil pressure and it's relationship to cooling the rod bearings is one of the most overlooked items that racers and race engine builders miss.Pressure is just the resistance to flow, increased clearances reduce pressure, but that's only part of the story, what a lot of builders don't quite get. I've found you can have great oil pressure and still burn up rod bearings, been there and done that. What I needed was increased oil volume flowing over the journals, to keep the bearing shells cool. Fail keeping them cool, and the plating on the bearings blisters, separates from the steel bearing substrate, like chrome plating bubbling up on an old bumper. The infamous 'glitter in the oil'. Once that happens, it's game over, the bearings need to be replaced pronto, otherwise the plating sluffs off, down to the steel core, and micro-welding takes place, bearing spins, crying and long faces, and a long tow home..
The rest of the video is pretty informative I just got to make one adjustment. note the tangs of a bearing are not to hold it from spinning the tangs are only a reference point to locate the bearing.. what holds the bearing in place is the "crush" how much the Rod Cap and the connecting rod crush the bearing in. the friction on back of the shells is what keeps the bearing from spinning. I'm not trying to take anything away from you Tony🤗 I just wanted to relate that to other people. 🤗 I think you did that to see if we're paying attention 👍🤗
Yes it's all about the crush. I'll take a rod slightly out of round with proper crush over a round one with bad crush.
Solid advice as usual UT 💪🏻
Such a common mistake here in Australia on the old Holden V8 engines. People will put a high volume pump on a very mild engine and just end up filling the rockers full of oil and not allowing enough time for it to drain back. Appropriate mods / oiling system work it can be done, but so many combos its not even applicable.
Worst one I saw was sustained high-ish rpm (drag race) with a high vol pump which starved the bottom end and spun a bearing or two.
Sounds like Oldsmobile Engines especially the Big Blocks 400/425/455.
@@GregHuston Mondello Oldsmobile engines has a fix for that. Go Lansing Ligtning!
I've always heard a minimum of 7 psi/1000 rpm too so I always assumed that was ok. The only time I've ever used a high pressure pump is on race only engines. High volume pumps can actually damage an engine if you run a stock oil pan. There's a chance that they can empty the sump and starve the pickup before enough oil has drained back down. I do disassemble the pump (new or used) and check the clearances as well as making sure that the mating surfaces are flat when I do any build.
Not true in all cases. I'm using a hv pump with my stock 402 pan in a freshly rebuilt 440 and never had any starvation/pressure loss issues no matter what rpm it's running. Yes, if you're low on oil or have restricted passages there's the potential for aeration, but try suspending over a gallon of hot oil in mid air.
My Dad used to say, high pressure oil pumps were good for sandblasting your bearings...
With the 4.6 modular if you have 4v heads, you have to have a HV oil pump, which came factory on 4v applications, but it's because you have to properly oil all 4 cams and give pressure to all 32 lash adjusters.
@@kramnull8962 I've never heard it called sand blasting but I know what he's saying. High pressure pumps can indeed "wash" the bearings.
@@Prestiged_peck It's fine as long as they're designed that way.
Tony's explanations are excellent!!! Especially when addressing things like this... Just the knowledge, of the effects of proper bearing clearance and the direct corellation of oil pressure and the condition of the bearings is good to know!!!
Perfect example of why I watch every single UTG video. Yes I've bought merch. Thank you for sharing Tony.
I was just talking about this with a mechanic! He said the same thing! Great video!
My 408 Cleveland hydraulic lifter setup has 2thou clearances throughout, it runs a Mellings hv pump using Brad Penn 20/50 and it achieves around 50 pounds at idle (warm) peaking at around 80 pounds at 6000rpm. It was built with a mild street aim with lower maintenance in mind. It runs most of the internal goodies with 245cfm rated 2V closed chamber heads limiting a couple of factors, home built 14yrs ago, on the dyno it made 250rwkw and still runs just the same today as I've only put around 14k miles on it since the build and it is maintained religiously. Your not wrong about parasitic loss though, it can quickly add up all over the place. It runs a large 7 blade fan surrounded with a good quality shroud, 1 big loss right there but I KNOW it's always doing its job, I carry a spare belt atleast. It's all horses for courses I guess, and what fits the budget at times. Great video once again Tony 🇦🇺👍
So your cam bearings are 2thou gap as well? Do you have to turn the cam a little to get the gap?
@@kramnull8962 Remac Performance here in Australia did the rotating assembly balance and line hone bored the camshaft/crank journals. I'm unsure personally of where the meat is missing, it was along time ago now. If it dawns on me I'll be sure to reply 👍
@Rick T I just described my build earlier.. Sounds exactly like yours.. High volume vs. High pressure is the answer I was looking for.. Thank you
Amazing presentation once again. Uncle Tony speaks off the top of his head, with the detail and sequence of a thoroughly organized engineering editorial. Must be all that writing experience! Thanks UT!
Good of you to bring to light this oil pressure issue.
This is something I also learned many moons ago, how parasitic losses both absorb power otherwise available for performance and decrease fuel mileage in the same manner.
This type of thing was a big part of what went into my customers engines.
The OEMs have only begun to take the parasitic oil pumping losses to the next level as of late.
Several manufacturers before, and now Chevy's C8 Corvette have ECM modulated oil pressure, the bypass used to reduce oil pressure to the much lower level required at a lightly loaded cruise condition, and then ramp it up under high load conditions.
And some say hot rodding doesn't contribute to improving production cars - I say bullshit.
I hate when I ask someone why they do something and all they can say is "well it's just what you do" or "this is just how I've always done it and it works fine". I'm not a hot rodder or even really a "tuner" (I just found this channel because I got an 88 Jeep YJ with an Edelbrock carb - first time dealing with a carburetor and was looking for videos about getting it set right) but still found this video hugely enlightening...the bit about how roller bearings will skid on oil reminded me of another video I had watched about how bowling lanes are pretty finely tuned by how much and what kind of oil is put on them and led to an "ohhhh so THAT'S how those things work" moment. I would LOVE to see more videos on topics like this that really dig into exactly WHY certain values are what they are...why do we run thermostats of a certain value? Why do we set spark timing where we do? What changes when we modify these values?
Thank you for backing up what I have been saying for years. Also, getting the oil to flow through the motor is cool. Ask anyone who has built a Cleveland.
most people don't know this, glad you did this video!
Finally someone has covered this subject while challenging the myths. I've been wondering about what is right and why for many years :)
I had a good 1970 360 F.E. with 20 p.s.i. and wanted to bump it up. I added a full qt. of Lucas oil stabilizer and got 80 p. s.i. WAY too much! Drained it and put a Pint of Lucas in and got 40 p.s.i. @5000 rpm. It was much happier and so was I!
There are two factors used for calculating horsepower requirements for pumps, flow and pressure . reduce either one and there is a reduction in required HP. Great video Tony.
Always great info! I've messed with oil pressures and oil viscosity for years and ruined a motor or 2 by bad thinking. Best advice is to stay as close to stock as possible if using stock specs on rotating assembly. On an old engine with low oil pressure a high volume oil pump may buy you a few more years. I used 50 w in an old engine thinking it would provide more cushion on my rods and ended up starving front 2 rods! So oil viscosity and not knowing what your doing can have dire consequences
This video is so good. Experience is what makes good content like this.
Thanks for breaking it down. I knew higher oil pressure cost horsepower, but I didn’t know the bottom line for running low oil pressure safely. Great job explaining 👍
I'm so happy he got it right concerning oil pressure. So many places wrongly advise high oil pressure is a goal. Not just cars but many heavy duty truck engines also run with low oil pressure from the factory. My International 392 cu in engine has been running less than 10 psi at idle for more than 40 years and I don't baby that work truck.
We learned that lesson back in the early eights. Playing with circle track cars, one year we say we were not going to have time to finish a new car and a new engine. A friend racing ARCA recommended a builder to us and we had a engine built. On delivery the parts list shown a stock mopar oil pump. When questioned his response was try it you will like it. He then ask about any problems in the past with engines. The only thing we ever had was a couple bearing failures. At that point he responded that we must have been running a high-volume oil pump and yes, we had been. He then informed us all were doing was overheating the oil and pumping it all to the top of the engine at which point the oil pump sucked air and the pressure drops to oh shit levels.
So glad you brought up the loose builds and more flow = more heat leaves the journal and less resistance to flow takes a load off the system.. The primary purposes for lubrication is lubrication and includes cooling. I love the oil wedge comments and how the oil enters the journal- it's why the oil holes in the shafts within the journals are located where they are. To maintain the oil wedge, where it feeds into the journal plays into the place where the journal is put under load- the compression stroke and is to cushion the journal as it loads.
I hear other rebuild guys talking about journal radius and side clearances. This does play into how well the oil will flow through the bearing- too much clearance will result in an oil pressure drop in the system and the oil viscosity previously run with a different clearance won't provide a familiar result. When refitting old Dodge crank journals with fresh shells, what advice can you offer for appropriate clearance? Not just what the plastigage says, but side clearance. What kind of journal side radius should I check for on a rejuvenated shaft journal and should I be chamfering the shells? I realize that loose is good, but to much of a good thing can be bad, too. Thx in advance.
If you've ever used an electric drill to prime an engine you can really Feel the resistance of moving the oil.
Great Video..
my 1974 kawi G5 100cc 2 smoker actually "pressure" lubes the crank mains
.
half goes just past the carb..... the other half drips on the mains
OVERKILL for a 100cc smoker that makes 12hp....
.
but, ive put 15,000 miles on the rebuild.... and i havent had a break down
havent even fouled a spark plug.... (but have replaced it when it wore out)
.
still starts first kick.... runs SUPER crisp.... throttle response is so good, really easy to rev match shifts up and down
.
.
i just LOVE that bike
Thanks for clearing this up. Guys on the forums are claiming 45 psi warm curb idle. I'm new to this and was thinking I had low oil pressure. The mopar shop manuals say minimum oil psi for 318, 340, and 360 is 8 psi.
Uncle Tony you are the best! At age 67 I finally understand the highs and lows of engine oil pressure. Thanks
Because oil likes to cling to itself and metal the faster a shaft turns inside a bearing the more oil it will pull into the bearing, yea it draws itself in. There are some of the new design engines that need some of that pressure to spray sufficient oil out piston cooling jets and maintain pressure on cam chain tensioners but even then it's not an excessive amount. I remember back in the 80's, Cummins changed there strategy on the 855 diesel in over the road trucks. They went from typical 65 to 75 PIS oil pressure to 40 Psi. Reduced oil shear, and parasitic load a lot. Mainly freaked out experienced drivers but it really worked. We had a small Detroit engine in a truck that at overhaul it got the incorrect spring in bypass. It had about 15 PSI more pressure than it was supposed to. After about 15 to 20 miles running down the road it would develop low oil pressure. Seems the excess pressure caused the oil to get hot from shear then it would be to thin, changed spring to reduce pressure and pressure drop went away. Love your stuff Tony and I'm not even a Mopar fan. Keep up the good work.
Good tips! As a very general rule of thumb if no specs specific to your engine are available, I agree that 7-10 PSI of oil pressure per 1K RPM is typically plenty. The only issue I have with this advice is the suggestion to use a thinner than specified oil to reduce oil pressure. Even if the bearings might be alright, the pistons, rings, cylinders, camshaft, lifters, pushrods, rocker arms, timing chain, etc don't know or care what the oil pressure is and may not like a thinner oil. As the SAE viscosity grade drops, the HTHS viscosity typically drops too. A quick Google search for "hths wear graph" shows why that could be problematic if taken too far.
I found and restored an antique Soviet Union KMZ Dnepr military sidecar motorcycle. You can call it the step brother of Ural sidecar motorcycles. It's oil pressure is 6 bar or 86 psi. While I was reading the manual I found the reason it's so high. It's for cooling and lubricating the Pistons because it's designed to operate at idle for extended periods of time. It's an air cooled boxer engine so you would think idling like that at 5km an hour would burn it up. The way it works is high pressure and volume oil is pumped to the crankshaft where it lubricates shell type bearings on the rods but then it sprays out of the bearings and into the back of the Pistons. It also produces a thick mist of oil that lubricants the ball bearings on the crankshaft and camshaft. That slinging oil also lubricates the cam lobes and lifters. Small channels guide oil down the pushrod tube's to lubricate the rocker arms and other valve components. The heads and cylinders have deep cooling fins as well. What's even more interesting is Harley Davidson made 1,000 copy's of them in 1942 and 43 calling them XA models for experimental. They were going to be used in North Africa but by the time the XA's we're finished testing North Africa was won and done.
Again, You are bang on Tony.
I grew up with the old - and I mean "old" school mechanics who had dirt floors in there shops and nicotine and oil / varsol permanently stained fingers. But man O man, did they know how to make mechanical things work and work better than stock in a lot of cases. I wish I could have absorbed more of their wisdom and knowledge but I retained as much as I could, and that knowledge has given me a great base to be able to work on or "hot rod" the modern engines as well.
Love your channel and you knowledge man 👍 I would happily push a broom around your shop and even clean the toilets just to be able to be around you when you're thinking out loud.
PS; I'm 60 years old, so it ain't no spring chicken doin the talk'n here.
It's hard to find someone like you, to talk to, about this exact subject! Thanks for all the info!!!
Well your video might be a year old but it certainly answers a lot of questions that I have wondered about for more than 50 years! In the 70's I used to build high revving high hp straight 6's. They often hit 8k Rpm I never went to route of high volume high pressure oil pumps cos I just didn't see the need. That's not to say I really understood, I just chose not to. Who would have guessed.
Tony,
Tim Arnott here, GREAT vid!!...and you are correct sir!!...my Pontiac has the RAIV Pump/pickup, usually described as high vol/pres.......it makes about 585 hp......i use a 10-40 wt cuz 20-50 wud create to much pres.....warm, at idle, i got 25psi........as soon as i get to 2500 rpm, i got 75 psi, all the way up to 6200 rpm......thats plenty......my brother wanted me to use 20-50, but i knew that was to thick, and to much parasitic loss, with no lubricity gain.......it runs fine, and 11:07 ET at 120 mph at the track satisfies me nicely.......GREAT VID!!
Probably one of your better informational videos. I was wondering about my low oil pressure during idle. Thanks.
Excellent video! Thank you. That helps explain why my big block with a melling high volume pump with a hemi pickup gets so hot!
Been watching for years and THIS is probably the best info you've put out!! Thank you!!
I DID get something out of this,Uncle Tony!I always thought you needed high oil pressure.This falls under the category of "less is more". This is good to know!
One of the top misunderstood engine rebuild topics!
I think I read about this in a Hotrod magazine once back in the 80's.
Glad you addressed it here again.
Thank you for crediting Bill Jenkins and especially (my hero!) Smokey Yunick. Over the years Yunick in his HP series books and contributions to Circle Track Racing magazine has enlightened many on the basic principles and physics of engines and related ancillary systems resolving the many unfounded 'myths' that have been around much too long. Keep in mind he 'schooled' the GM engineers more than once proving what actually happens inside motors vs the misconceptions they held for decades.
Don't forget the number of times he outsmarted the NASCAR tech inspectors, some of which is legend. He did the same moving to Indy then later to Trans Am. A genius, always looking for answers that most never considered.
I remember my dad had a truck that when it was hot the oil pressure went to 0. Ran well. The real bearing ability comes from hydrodynamic pressure. This is from the “ wedge” that is built from spinning parts. That hydrodynamic pressure is from the lubricant not the oil pump. If you do the math 50 psi will not stop engine wear if there is no hydrostatic pressure.
I have a 1964 Galaxie 500 with the 352 FE motor. When I rebuilt the motor 30 years ago the rebuilder said to use 10w 40 as a break in then 20w 50. He has retired and closed up shop. I talked to another mechanic and he also said to use 20w 50. Although the owners manual from 1964 says to use 10w 30. I use the 20w 50 but change it every year even if I only put 500 miles on the car. I also add 1/2 qut of marvel mystery oil.
My old 55 Studebaker 259 idles at 10 psi hot , I did a lot of clearance work to the oil pump and bearings too . Always thought that was low , but it is the way the engineers designed it . Thank you Tony , another Tony from Hemet , CA.
A Studebaker v8's pressure regulator is to the timing gear teeth, not at the pump. I run near 40psi all the time using 15w40 CC/CD type oils. Do you have the restrictor in line with your oil filter? otherwise you have more clearance than you should. Are you still using the floating oil pick up, and is its pivot not sucking air. If you are using a C4 oil filter, are you carrying your oil higher than the stick, or check the level before the filter drains back to the pan? I inverted the P-50 style filter on a few so the filter is always full. The oil relief valve is what oils the teeth on the timing gear. As a C4 style fills, the level in the pan drops. If using a 56 or newer pan, you are already short a quart. Last oil pump I did involved a little lapping to keep the plate close to the gears. Lastly how was your cam bearings? have fun
This was helpful my 5.7 goes down to 7-10 at idle so I idled it up some. My last van was doing that and on a hot day in summer at a stop light it went to zero or close. Put in an oil pump and it had a knock so installed rod and main bearings while in the van and it spun a bearing after about a year of light use. I hope this van doesn’t do that. 2001 GMC Savana 3500 145,000 miles.
My tired old 350 Buick motor when hot, idles around 10psi and runs 30psi when cruising down the hiway. No knocks. No ticks. And in my 66 Chevy truck with a 3.08 gear and a quadrajet, I can squeak out 17mpg on the hiway. 15.5 if I cruise around 70-80.
Maybe not the safest thing to do, but running 1qt low can keep your crank from dragging through the oil and free up horsepower as well. I run an 8qt pan on my Small Block Olds and only run 7 quarts, no need for fancy windage trays and reduces the parasitic drag.
It's totally safe. Even run only 5-6 qts.. Windage trays are still a good idea to use.
👍 in the past I never gave or oil pressure of thought Beyond making sure I had "normal pressure".
Then I started building VW type 1 air cooled engines for my airplanes. Fortunately at the local engine machine shop the gentleman informed me of the dangers of too much volume when I said I was going to go with a high-flow oil pump. He advised against it stating cooling issues. That plus it has no gear reduction too the prop. Just straight flywheel Drive. 3200 RPMs Max. Cam makes its power between 1,200 and 3,000 rpm. Approximately 160.hp
Thank you so much, I could never find any help with oil pressure in my LS2 so this is just what I needed
Love your old school knowledge! Keep it up! You have leaps and bounds more knowledge than most of these builders on YT!
Great video finally some true facts. Also I wish somebody would do a video of oil pressure vs oil volume, completely different things.
Thanks for your video I was told my 396 at hot idle was to low between 15-20 when you step on on the gas it raises up to 30-35 at 185-190° cold idle is 50-55. I was considering a high volume oil pump burning after your video I feel much better about it. Thank you. 👊👍
I'm so glad we have tony he has helped me tremendously it's so hard to find good no bullshit information I bought a high volume for my 408 I put in my pickup because everyone tells you to but what your saying makes complete sense I'll use thinner oil to compensate for now lol
243K miles SBC with condensation in the oil. 5lbs Oil Pressure at warm idle. Wore out? Wrong.
Factory Dash gauge was wrong. PVC valve at TBI clogged. Installed manual gauge = 20lbs at warm idle. Cleared PVC system= no water in oil pan. Sometimes its the little problems. Rebuilt the Motor then found the real problems. Completely clogged PVC tube in TBI unit was missed by 3 mechanics.
The roller bearing bottom end of your Sportster is pressure fed, as were the rod bearings of the Big Twin V-Twins from that era.
The “full flow” roller bearing bottom end on Big Twin machines from ‘73 though the last EVO, stopped pressurized oil to the connecting rods below 12 psi at idle to maintain adequate pressure for the hydraulic lifters; Ironhead Sportsters prior to ‘86 all had solid lifters.
The pressure relief valve in the pump would open the passage to the connecting rod roller bearings at 12 psi. This is why at operating temp you would not see an oil pressure rise above 12 psi on a stock machine.
Tony: Thanks for the insight into oil pressure and it's causes. Any information about oil pumps, especially SBC oil pumps, is greatly appreciated as well. The reason for this is that I can't find a great deal of information about oil pumps with the cause and effect situations in my studies. Again, you help is well taken seriously.
Uncle Tony and Uncle Ted are my favorite Uncle’s!!!
I use to sit in smokey yunick office when my old man use to talk to him. U were a big help I have a 300 6 banger at idle is has about 7 psi it has 210000 on it
I have an early HD Panhead and the service manual reads oil pressure 35psi, 20 psi at 20 MPH. It is adjustable. Timing case gears are bushed. The main shaft is roller bearings which are "air cooled". The rod big end is roller bearings that are oil cooled. The rods fling oil all over and need good pressure/flow to not over heat. Thinner oil does ccol better.
years ago, I had a friend who was running a "TRANS AM" at the drag strip. he was always breaking the oil pump shaft tangs off at the distributor, and loosing engines. I asked him what the oil pressure was, he said "I DO NOT KNOW--- IT IS PEGGING THE GAUGE" ( over 100 psi) I told him "THE MOST OIL PRESSURE YOU NEED IS 40 PSI, YOU ARE NOT RUNNING A DUMP TRUCK" he changed the oil pressure relief spring in the pump and got the oil pressure down to 35 psi( when making a pass) he thanked me for the fact he went from a 12 second machine to a 9 second machine, and did not loose any more engines!!!!, you are "SPOT ON" when it comes to oil pressure, I remember the 472/500 cubic inch cadillack engines that were set up with 20 psi oil pressure from the factory and never had any problems. the auto industry had federal mandates that had to be met by a certain date, when it came to fuel consumption, they did it by running ultra light weight oils without modifying a thing on the cars/ trucks that they were producing!!!!
In my fiat punto 188, the manual says at list 0,7 bar at idle and at list 4 bar at 4000 rpm, just saying. Also a lot of truth in this video!!! keep it up!!
oil pressure and recommended oil types is the most misunderstood thing in shade tree mechanics. i know people that run extremely high viscosity oil in their daily drivers just because that's what pro-mods run, so it has to be the best oil, lol. everyone knows someone that knows someone, so that's why they run oil completely different than what the manufacturing engineers specified for their vehicle from the factory. just run the weight that's in the operators manual. if you have low oil pressure then something needs repaired. running extremely thick oil just to increase the pressure may cause wear if the oil is too thick to flow into the actual clearances. uncle tony just put out a great video and clarifies a lot. bottom line- research before choosing an oil if you have a custom build. you should know the targeted clearances before you ever build an engine. the oil you need is based on the clearances you have. using the wrong oil will cause premature death to any engine.
WELL SAID! Just that simple! A pump creates flow while a restriction creates pressure 8 why it's necessary!
Saw my old buddy Ron Ward in one of your videos. Great guy. Many of us miss the old days!!!!!!!!!!!!!!!!!
UT, what makes you great , among other things is youre true passion !!! KUDOS to you man ..
Tony, here's another trick to reduce parasitic losses, and Mopar-specific: The first CAST crank big blocks had a weighted balancer, with EXTRA weight on one side. LATE 70's cast crank big blocks weighted the balancer by REMOVING metal from the OPPOSITE side. The difference is probably 1 pound, a lot of weight at 5500 rpm. I've never heard you mention that.
I learned something today, thank you
I have shown people about this with our dirt late model dry sump pump. It has an adjustment screw. When your idling at 900 rpm with 50psi oil pressure and you turn the psi down to 10psi and your rpm goes to 1200 with no carb adjustment they see the light real quick. We run .0025 to .003 for our rods and mains we run restricted oil passages to the lifters because they are solid rollers...
We ran circle track dirt posse car back in the late 80s. 383 mopar 30 over 10.5:1 popup TRW pistons, 8 bolt truck crank, aluminum flywheel on methanol. Holley alcohol carb 830CFM. Solid lifter with adjustable rockers, edelbrok torqer manifold, 1 7/8" headers with spiral wound half muflers.
To the point, we ran loose clearances with a high pressure, high volume oil pump and Valvoline racing 50 WT oil. We'd see 60PSI idoling and a bit higher hot at 6,800 RPM.
It had a grunt sound like it was trying to shotput the car down the straights.
Good times.
Tony I'd love to see you do a piece on oil pressure vs. Oil volume and how misleading oil pressure can be. For example a high oil pressure reading can actually be an obstruction while the engine is actually starving for oil. And on the other hand a lot of oil can be flowing, lubricating everything in the engine without really registering a lot of oil pressure.
Some modern cars have a variable displacement oil pump for saving fuel. The ECU will command a valve to reduce oil pressure.
I used to have a VR6 VW where the oil pressure relief valve had failed. On a cold start the pressure would go so high it would overpump the lifters and make the engine misfire!
Man, I've been wondering about oil-pressure ever since I did my last rebuild because I added eight wrist-pin oilers plus one for the timing chain; and even though I used a Melling HV "SharkFin" with a washer in it, my pressure warmed up at idle was still less than the 20 psi I was accustomed to seeing. That kinda freaked me out; but on the other hand I didn't really see anything I could do about it without another engine pull and I consoled myself that it was less drag on the sacrificial distributor drive that would all too often let me know it was done by retarding my timing. I'm running a polymer one now with the hope it will outlast the bronze ones; and I think it already has. I was relatively sure this was a case where less was more; but I certainly appreciate the affirmation you've given because it does give me more peace of mind. I've been turning wrenches for 47 years now; and yet there's always something new to learn and now days, MF-ers are just going off the chain with their CNC billet blocks,carbon-fiber rods, mirror image turbos, and dual OHCs. Everybody is making more than they can put to the ground on a last chance power-glide for numbers. LOL I'm just an old street-freak trying to keep the 2.0 L turbo crowd off my ass. Still fun S though ain't it man? Thanks for sharing.
Last chance power glide , that was good. thank you for your comment
Most of us already know this but I just purchased a pinned distributor shaft right from Mopar performance.
It's amazing they relied on a press fit gear.
Thank you for this. So interesting. This has put my mind at rest regarding my Healey 3000 oil pressure when engine is hot.
I have a 455 olds in my rv, it's low rpm, all the guys that know suggest a high volume pump. Currently on my old 110 000 mile motor I've been using heavy oil 20 50 Lucas with zinc. At idle hot it will be at 11 lbs. If I'm using a 10 30 oil, I'll have less than 5 lbs hot . The manual says straight 30 w for 1976 . My current motor is getting tired I think, compression is 150 lbs across all. One of the gurus on this motor told me not to look at the idle oil pressure at all and run synthetic for the cooling, and to run a thin oil so that it would return to the oil pan quicker.
Man I used to have those manuals in my 20’s. 30 years later I need to find copies.
Interesting. I've always been told and followed for hot pressures.
5 psi per 1000 rpm for lower rpm, lower compression motor (less than 8.5:1).
10 psi per 1000 rpm for average rpm average compression, 6to 6.5K rpm up to 11:1 compression.
15psi per 1000 rpm for engines with power adders.
Drop pressures 1-2.5 psi per 1000 rpm if the engine is priority main oiled.
Ahaa yes...that brought back memories as in Windsor vs Cleveland 👍
I love all these tips....this one I new not because I am a great mechanic but because I have a memory like an elephant. Its also common sense. At some point in going to build my very first 383 stroker for my square body suburban. People swear I won't be able to get fuel economy out of it but I'm doing enouph research first I will prove em wrong! I wish I lived close, I was like your favorite nephew and you wanted to give me advice on my build......Lol
Great info! We novices always think more is better and put a high volume pump on a stock rebuild....
Exactly what you said..been doing this for 40 years street and race motors. Always been 10lbs per 1000rpm
While I have [relatively] high oil pressure on start-up [50 psi], soon after warmup, the pressure drops down to about 25 psi, and will only go up as the RPMs climb up near the top. While I did nothing to this engine [internally], this is an International Harvester 392 I/C and it seems to self regulate and keep its psi at the right pressure per RPM.
Hi Tony, I'm new to your channel. This video is what ive been looking for. I just finished building my 2005 5.7 hemi with the eagle heads from a 2017 5.7. I installed a MELLING high volume pump thinking the obvious, more oil, more lubrication, more fun. The psi at cold stay would be 40-45, and dropped to like 30 when hot. But I noticed the oil light came on after driving like 20 min, and then it would shut off on me, and it would not wanna start, sorta like limp mode. Psi wouid go down to 15, but i thought that was not normal. I basically have a "stock" rebuild but, after seeing your video, I think ill have to put in a new stock oil pump. Engine barely has 45 miles after being rebuilt.
Luv the wisdom. Its like gettin ya papers, i used to know what it did ,but now i know why it does it.
7 for ever. G
I ALWAYS WENT WITH 5 FOR EVER G
that was as low as I thought I could go with sticking metal together. I usually have more but the 5 has been in my head since the 70s why? I don't know probably read it one of those silly California car magazines. You live and learn.
These was a good video thanks.
Really good, and not talked about much. Remember talking to the Craftsman Series Truck Racers/Drivers in the pits, and I asked about the breathers on their crankcases and a few of them went to explain that they were playing an oil pressure game at (I think) they said @ 8500RPMS; the take away for me at least in this capacity seemed to be less is more.
I don't know for a fact , but oil pressure is also based off journal diameters as well. Small journals need less oil pressure than large journals. Not sure how many, but newer cars are controlling the oil pressure , so it only gets what it needs for MPG . Another thing to touch on with high volume oil pumps is with out added capacity you might pump all the oil up top, run the sump dry and blow up the engine. All engines are different as far as that goes. Olds Engines would do that for sure, and when I bought some parts from Mondello decades back , they pretty much said do what ever it takes to get a larger supply of oil if running a high volume oil pump.
one thing I know, I need more than 0 psi at idle, and more than 5 at 1500 rpm. so I swapped the stock pump for a high volume pump and now I get 5 at idle and 10 to 15 driving around. stock german 2.8 v6 from a 78 mustang in a 77 pinto wagon.
Built BBC back in the day, got great advice then: stock oil pump.
Fast forward 20 years later 40k miles- stock oil pump has been great for 400hp
Love it learned in the late 70s about facing round track love the real old school info
I watched a test where a high volume oil pump only took 5 peak hp from a sbf on the dyno!
That being said I ran a HV pump on a well built stroked 8.2 deck ford (302)
Would see 7000 Rs on a regular basis , mechanical cam , good heads etc. 3350 mustang ran 10.80s n/a
After about 5000 miles I noticed oil pressure was lower than normal..25 psi hot idle when normally it was about 40 hot idle.
No noises , ran good etc…parked the car and took the motor apart that winter…..bearings looked absolutely beautiful (in fact I reused them on an old truck motor I was limping a long) …long story short the block had cracked up the front of a main journal into an oil galley….
All the wearable parts in the motor looked great……I’m sold on more oil pressure than needed ….
To be fair I ran a 10w-30 all summer too and bearings clearances we’re nominal @ .003
So oil was a little thinner with a high volume pump….work good for me.
This may be the first video I ever share. And, subtly probably one of your most important yet Tony! Great! Stuff!
Engine masters just did a test on this. The oil pump takes almost zero hp to turn but the point is the same. Alot of times if you don't need the extra volume a high volume pump will fill the heads with oil and not able to drain down enough and starve the bottom end
I really need to get an oil pressure gauge for my 96 Buick LT1. I had a quart a day rear main seal leak. So when I pulled the engine to change the seal, I put in a Melling high volume oil pump. I figured a 25 year old engine with 150k miles might need more flow. Looks like I should've done more research. But I've been driving it for over a year like that so I guess it didn't hurt too much. Not that I can tell anyway. I definitely need a gauge though. I'm really curious about how much pressure it actually has.