Oil Pressure- How Much Do You Need And Why
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- Опубликовано: 2 окт 2024
- Some pressure is good, but too much can hurt horsepower as well as fuel economy. Here are the basics as they apply to the typical production based Ford, GM and Mopar high performance street cars.
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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
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.
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. ;)
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
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 ?
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
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.
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!!!
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.
This video is so good. Experience is what makes good content like this.
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.
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.
If you've ever used an electric drill to prime an engine you can really Feel the resistance of moving the oil.
Great Video..
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!
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..
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'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.
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
Excellent video! Thank you. That helps explain why my big block with a melling high volume pump with a hemi pickup gets so hot!
It's hard to find someone like you, to talk to, about this exact subject! Thanks for all the info!!!
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.
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
Great video finally some true facts. Also I wish somebody would do a video of oil pressure vs oil volume, completely different things.
UT, what makes you great , among other things is youre true passion !!! KUDOS to you man ..
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 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.
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.
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!!
Thank you for this. So interesting. This has put my mind at rest regarding my Healey 3000 oil pressure when engine is hot.
I learned something today, thank you
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.
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
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
Been watching for years and THIS is probably the best info you've put out!! Thank you!!
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.
Luv the wisdom. Its like gettin ya papers, i used to know what it did ,but now i know why it does it.
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.
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.
Just wanted to say, Happy Thanksgiving uncle Tony, and family..
Love it learned in the late 70s about facing round track love the real old school info
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.
Ford's 7.3 Godzilla have variable displacement oil pump and it helps improving the engine efficiency. Gotta find a way to convert your classic with variable displacement oil pump.
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.
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.
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.
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...
You've got pressure and clearances a little bit backwards (at least in what you said - I also have ADD and getting my thoughts into words can be a challenge on the spot).
Race motors have larger clearances, so they need more FLOW to keep the pressure up. You put that 120 psi pump assembly in a stock Hemi and you might see more like 200 psi at idle - if it runs.
Pressure - oil or boost - is merely the result of a choke point in a flow path, so, if blow out your choke point by expanding the bearing clearances in your bottom end or flowing your cylinders heads in a supercharged application, you're going to need a lot more flow to maintain the desired pressure.
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.
The Vaz-2101 russian engines commonly have almost no oil pressure, because right next after the oil filter, the oil gallery goes to the distributor and oil pump drive bushing, which when it wears out, all the oil goes there. my Vaz has barely 1bar (14.5PSI) of oil at 6 thousand rpm, and these engines run fine with this low of an oil pressure, I guess because it still has oil, it's fine, but when you start getting air in the oil you'll seize the engine quickly...
Good info for durability. External oil cooler helps in certain applications. VW bug were air cooled and oil cooled as were Buells. Early engines had no pump, just splash but they had solid lifters, low RPM. Oil pressure on old engines was low like 4 psi at idle, again low compressio, low RPM, solid lifters.
This video is worth a like for sure
Thanks for explaining this. Haven't been able to find anything explaining pressure and where it should be.
I appreciate your knowledge and videos. Keep it up.
I only use stock NOS (Napa Balcamp branded) Melling M55 oil pumps on SBC builds no high flow and no high pressure....High Pressure pumps force the oil filter bypass valve open and high vollume ones fill the top of the motor full of oil...no need for that on street cars. Also the super oil pumps steal HP and torque....normal standard pump is more than adequate for most builds. I add 2-4% MOS2 Molycote oil Additive to oil that prevents cold start wear, Army does the same. Old Ferraris have worse oilpumps compared to a stock Chevy pump ;-)
So glad you are covering this!
brilliantly explained
I was just talking about this with a mechanic! He said the same thing! Great video!
Damn Tony,
I think this is the best video you have ever done.
Bad ass!
351w here 35psi warm typically 40psi on a mild day stock pump never seen any ford stuff on your channel but same with my 302 also had about 60psi cold 40psi warm and thats after the rings disintegrated and the bearings were ran dry it still kept a good 40psi warm
Great video! Goes against what people that never advance past teenaged automotive engineering think.
The makers of performance oil pumps hate you right now. 😆
Tony !!!! you are giving all the secrets away!!!!
Good morning Tony this was very eye opening, could you please do one on oil coolers/ external filters/ good and bad engine temp etc. thank you your videos are the best😊
I’ve run Dyno test on small block Chevy on this very subject no long ago. The amount of power needed to spin oil pump is barely discernible on the machine I use. Tried stock and aftermarket pumps. Different max pressures and even different oils. I never saw anything that would amount to anywhere near 5 hp from the most drastic measures taken. Most engines it’s much less. That being said, Adequate oil flow across the bearing surface to remove heat is much more important than the pressure of the oil being pushed through. I’m all about reducing parasitic losses but I don’t feel the gains from reducing oil pressure is worth the risking damage to your engine. It’s true that some high dollar race engines don’t run as much pressure as they might have at one time, but they also have the resources and research to know that they’ve got adequate flow to keep their bottom end happy. That’s not something your average DIYer is going to know for sure.
Dang I want that XLCH! Quit showing it to us!!!!
Also, my buddy's brother's friend had an oil pump, that used very little oil. Someone came in the middle of the night and stole it! Probably some oil company shenanigans, lucky no one got killed.
Hi uncle tony thank you for your a good video on oil and oil pumps 👍. Would you be able to do a video on mechanical fuel pumps thank you
Great explanation, thanks for posting.
That was very interesting Tony. Thanks.
Harley had to collaborate with Porsche on oiling in developing the Twin-cam 88. Interesting story and a case of less oil = better cooling.
3:12
I remember going through A school in the Navy; was taught oil has three functions; it cools, flushes, and lubricates.
Just switching from a 4-groove crank pulley to a 2-groove on a 440 also saves hp. And of course, the Mopar clutch fan, although an electric fan and water pump are even better. But electric water pumps are expensive.
The old 71 series Detroit Diesel manual said that 2 psi per 100 RPM was just fine.
The other bad thing is with a stock oil pan and a high volume or high pressure pump you can suck the pan dry rather quickly and starve the engine.
I have rebuild several 4.0L engines, and I always find that the camshaft at cylinder 6 needs more oil and pressure. With a high volum/pressure oil pump, that is not an issue any more.
in the 70s i had a 49 ford PU, it had a 292 engine. it had 10psi on the road and 5psi at idle,,,,,,,,,,,,,,,,,,,,,
You got that right! Drove my Jeep with a 360 in it for about 20 years, and that dam thing never had more than 7 psi at idle, and that was running 20w 50. Crappy ass oil pump, is what it was! LOL!
TONY, YOU'RE THE MAN. THANKS FOR SHARING.
Tony do a follow up video on the difference between between a high volume and high pressure oil pumps
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!
On a related note...the "W" in say, 10W40 doesn't stand for weight...it stands for winter...the oil has been chemically treated to flow like a 10 weight at freezing...
The rule of thumb for road racing engines. Was 10 psi per thousand. Unless run on a dyno and verifiyed for that engine at temp and load. But people that lowered their oil pressure would have reliability problems. Have you tryed enlarging the pressure relief passages and a lower spring pressure.
Just what I needed to know. Thanks again UT.
Perfect example of why I watch every single UTG video. Yes I've bought merch. Thank you for sharing Tony.
This video is loaded with info!! Thanks so much!
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.
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 love your stuff. My old Harley Pan gets pretty low at idle when hot. But that's ok.
My 95 mustang 5.0 that's turboed has 22psi at idle in drive but when I start to drive it goes to 45psi instantly and it's been that way for 6 years now I don't know if it's been longer but I noticed that 6 years ago and still drives beautifully and strong
Great video, I have never heard it explained like this. I used to have a couple of v10 dodge trucks, they had almost 60 pounds of oil pressure at idle, I wonder why.
Back in the 80's and 90's when Valiants were affordable (Australia), the idle oil pressure for the Hemi 6's was about 60psi cold and about 50 hot. These were older engines from 1970-77 some of which were re-ring+ rod bearinged, others untouched original. Good oil (castrol gp50 as promoted by top doorslammer racer Ben Bray) which always did a better job of quietening the Hemi's thrashy hydraulic lifters. Only the holden red motors would dip right down to 10 or so psi hot at idle which we considered shit.( those same tired holden sixes would rattle the big ends when started cold if they were revved a bit on immediate startup- flashback to a neighbour 5 houses up the street starting his HQ Kingswood every morning!
@@rossbrumby1957 that's cool, ever since I saw mad max as a kid, I've wanted to see your country and drive some of your cars.
I rebuild my 5.9 magnum engine on my 01 Durango and I used the recommended oil and my oil pressure looked way too low but it performed better than after I started using 10-30w. I felt like it was a little too low the pressure but I think I'm going to switch back and lower the pressure. If I feel like it has more power then that means it's better for the engine.
I rebuilt my 440 in 1991 just rings rods and main bearings direct connection high flow oil pump , windage tray under 500 lift hydraulic cam I have 75 PSI at idle if you put on a standard oil filter it will puff it out like jiffy Pop popcorn this engine was bracket raced Street driven it's had every right to throw a rod several times over and still run strong should I reduce oil pressure or just keep going
Great content. Spot on
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.
Only reason I put a high volume/high pressure oil pump on my sbc is cause for one I have a 8 quart oil pan second I have a remote oil filter and oil cooler. I needed an oil pump that could feed all that extra stuff an keep the motor feed. The shear amount of oil in the pan I know it won’t run dry.
if that what smokey and grumpy went by, that's more than good enough for me!
I remember a mechanic told me that my engine was wearing out cause my oil pressure was dipping too low at idle. I don't quite understand this.
Bearing clearances are increasing from wear. At lower RPMs that thing is bleeding oil faster than it can keep the pressure pumped up. You notice it at idle. Larger tolerances are from a worn engine. That's what he means.
If your engine is high mileage it could be be your bearing clearances are now bigger causing the lower oil pressure. If there's still good compression in the cylinder like UT says experiment with oil viscosities. My 5.3 lost oil pressure due to a bad o-ring between the pickup and oil pump once I replaced that I was back to having good oil pressure, so sometimes it's not the engine that's worn just a $4 rubber piece). In high mileage engines I like to run a heavier oil to bring the oil pressure up if it was a 5W-30 oil new, I run 5W-40 and on some really worn engines just throw HD Diesel oil in there took one worn out 307 from 20 psi cold to pegging the gauge at 60!
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.
you didnt mention volume , and drag racing. its come up alot high pressure vs high volume. what happens on deceleration . this is important as well to the usage of the engine for example oil drain back and restricting oil to the top end on certain priority oiling systems.
completely makes sense!!! definitely got some outa that, thanks!
Your the best dude!