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Oil pump question

I like this chart. But it doesn't mean much if you don't know your clearances.
It does support what Doug wrote, the numbers don't lie.

Viscosity.jpg
 
The engines in our classic Mopar muscle cars are over 50 years old. There are problems associated with this. One recurring theme you will hear about on the forums every single month is “low hot oil pressure”. Yes it’s true, you have low hot oil pressure. Don’t panic. Your engine is not going to “blow up”. It will still make plenty of oil pressure when you are driving because the oil pump is turning more rpm’s. But when you are idling the engine is turning 800 rpm’s. That means your oil pump is turning 400 rpm’s. Engines wear. This wear causes the clearances between the parts to become larger. Sooner or later the clearances between the 5 main bearings, 8 rod bearings, 5 cam bearings and 16 lifters will become large enough that the volume of the stock oil pump at 400 rpms isn’t enough volume to build the pressure it used to have when the oil gets hot, so the pressure builds to less psi than when new. Even if your engine has been rebuilt people aren't going to set the bearing clearances as tight as when they were new. There are ways to solve this problem. Sometimes you can just idle the engine up. That will help a lot. If that’s not possible you can go to a heavier oil. People had been running 50w in Mopars for 60 years. Or you can install a Melling M-63HV high volume oil pump. That is probably the best way out for your car. It looks like the stock M-63 Mopar oil pump on your car but the rotors are around ¼” longer to give you 25% more volume. It’s only 4 bolts to replace and it is fairly simple, but I would use ¼” longer bolts to put the HV pump on. Now your “low hot oil pressure” problem should be fixed and the world will be a better place to live.
 
rickseeman said:
The engines in our classic Mopar muscle cars are over 50 years old. There are problems associated with this. One recurring theme you will hear about on the forums every single month is “low hot oil pressure”. Yes it’s true, you have low hot oil pressure. Don’t panic. Your engine is not going to “blow up”. It will still make plenty of oil pressure when you are driving because the oil pump is turning more rpm’s. But when you are idling the engine is turning 800 rpm’s. That means your oil pump is turning 400 rpm’s. Engines wear. This wear causes the clearances between the parts to become larger. Sooner or later the clearances between the 5 main bearings, 8 rod bearings, 5 cam bearings and 16 lifters will become large enough that the volume of the stock oil pump at 400 rpms isn’t enough volume to build the pressure it used to have when the oil gets hot, so the pressure builds to less psi than when new. Even if your engine has been rebuilt people aren't going to set the bearing clearances as tight as when they were new. There are ways to solve this problem. Sometimes you can just idle the engine up. That will help a lot. If that’s not possible you can go to a heavier oil. People had been running 50w in Mopars for 60 years. Or you can install a Melling M-63HV high volume oil pump. That is probably the best way out for your car. It looks like the stock M-63 Mopar oil pump on your car but the rotors are around ¼” longer to give you 25% more volume. It’s only 4 bolts to replace and it is fairly simple, but I would use ¼” longer bolts to put the HV pump on. Now your “low hot oil pressure” problem should be fixed and the world will be a better place to live.
Click to expand...
I think that this is the way to go. I will try the Melling 63hv. If that doesn't help, I'll bring up the idle.
 
I guess I should also say that the 1965 Super Stock Dodge owners manual says 8 psi idling is fine for a Race Hemi. But you and I would like a little more. I get that. But I think your engine is fine just the way it is. You have 15-20 psi. A high volume pump would be to please you, not necessarily for your engine.
 
rickseeman said:
I guess I should also say that the 1965 Super Stock Dodge owners manual says 8 psi idling is fine for a Race Hemi. But you and I would like a little more. I get that. But I think your engine is fine just the way it is. You have 15-20 psi. A high volume pump would be to please you, not necessarily for your engine.
Click to expand...
I agree. I would be happier with a little more. I will try changing the oil, and then try idle speed, and timing. Then, if I feel the need, I will try a different pump.
 
You are seriously overthinking it and are worrying over nothing.

Do some research on lubrication. As long as you have a film to prevent metal to metal contact, additional pressure will not help, and in fact most likely hurts you.

My 574 was built by Tony Bischoff. Don't get better than Tony. That motor I believe is right around 20 psi at idle (over 1000 rpm), and never gets to 70 psi. 1060 hp and spins to 8000 rpm. Have not really put it to test yet, but should have good reliability according to Tony.
 
Do what I do. I was given a couple cases of oil when a friend sold his jet boat and didn't need it any more. I'm determined to use it. So I throw in one quart per oil change on the street/strip cars (8qt cap), and the diesel trucks.(10-14qt cap)



Straight 50wt. 20 quarts to use up...... thick as good maple syrup.
 
65CopCar said:
You are seriously overthinking it and are worrying over nothing.

Do some research on lubrication. As long as you have a film to prevent metal to metal contact, additional pressure will not help, and in fact most likely hurts you.

My 574 was built by Tony Bischoff. Don't get better than Tony. That motor I believe is right around 20 psi at idle (over 1000 rpm), and never gets to 70 psi. 1060 hp and spins to 8000 rpm. Have not really put it to test yet, but should have good reliability according to Tony.
Click to expand...
Yup, I'm a professional over thinker. After reading all the comments, I feel better.
 
To further muddle your mind. My 440 is 30yr old since “put together “ in the 80’s. Don’t even ask me the bearing clearances, probably 20k on motor; 40# idle @750rpm, 80# above idle with 57yo original oil pump and 15w40 Rotella. It does have a 5/16”(?) lock washer behind the spring for little more tension. IMHO, ur over worrying. Even at operating temp it’s still above 30#.
 
oldbee said:
To further muddle your mind. My 440 is 30yr old since “put together “ in the 80’s. Don’t even ask me the bearing clearances, probably 20k on motor; 40# idle @750rpm, 80# above idle with 57yo original oil pump and 15w40 Rotella. It does have a 5/16”(?) lock washer behind the spring for little more tension. IMHO, ur over worrying. Even at operating temp it’s still above
Click to expand...

furyus said:
Guys, I have a 505 stroker that is all new. Roller cam, Indy heads.
When my engine gets warm, around 190*, the pressure drops below 20 psi at around 800 rpm. This is the same thing that it did with the old 440. I used this pump because it was new. So, I need an oil pump that has higher output at idle rpms, but not at higher rpms. So my questions are, if I shim the pump, does that raise the idle psi? If not, then I need recommendations for a new pump. I don't want to use a stock style, cast iron pump. I'm looking for something that is maybe billet, but mostly I just need one that puts out more at idle. Thanks
Click to expand...
A curiosity question.....do you know what the main bearing clearance is??? Do you know what the rod bearing clearance is ??? Are the lifters loose in their bores????...did you check? ALL GALLERY PLUGS ARE IN PLACE..... It's NOT a matter of shimming the oil pump high pressure relief valve spring but very likely a bearing clearance issue. I'm a fan of using a MELLINGS HIGH VOLUME OIL PUMP. I use 0.002" - 0.0025" MAIN AND ROD BEARING CLEARANCE.....w/ 10W-30 MOBILE ONE oil, the same Wix filter and get 60 psi hot idle oil pressure at 1200 RPM and 75 psi pressure at 3000 RPM. The bearings are Clevite 77 tri metal type, FULL GROOVE MAINS to provide 360° Rod bearing oiling.......there are many variations.....pick the one that suits you.....just my opinion.....
BOB RENTON
 
Do you by chance have an oil temperature gauge? As long as you have sufficient volume flowing to keep the bearings cool and lubricated, 15lbs at 800 shouldn’t be a concern.
 
RJRENTON said:
A curiosity question.....do you know what the main bearing clearance is??? Do you know what the rod bearing clearance is ??? Are the lifters loose in their bores????...did you check? ALL GALLERY PLUGS ARE IN PLACE..... It's NOT a matter of shimming the oil pump high pressure relief valve spring but very likely a bearing clearance issue. I'm a fan of using a MELLINGS HIGH VOLUME OIL PUMP. I use 0.002" - 0.0025" MAIN AND ROD BEARING CLEARANCE.....w/ 10W-30 MOBILE ONE oil, the same Wix filter and get 60 psi hot idle oil pressure at 1200 RPM and 75 psi pressure at 3000 RPM. The bearings are Clevite 77 tri metal type, FULL GROOVE MAINS to provide 360° Rod bearing oiling.......there are many variations.....pick the one that suits you.....just my opinion.....
BOB RENTON
Click to expand...
I don't know what the bearing clearances are. I had the machine shop assemble the rotating assembly. Nor does the 440 source website mention whether or not the bearings are grooved. If I idled at 1200, then it would be at a more reasonable pressure.
 
Who knows what clearances are on most of our engines! I have no f'n idea on any of them. Bee was rebuilt in 1986 for $300, it runs 60 all day long, 30+ hot and sitting at a light. The Hemi in the 66 runs too high IMHO.. 90 cold... then 80 hot, but drops hot to 40 at a light. My Superbird has had pretty much zero oil pressure on 20W50 for 35 years... I switched to Penn Grade a couple years back and for the first time it showed 20 psi at speed. Still zilch at idle. Confirmed with a mechanical gauge... doesn't knock and I've been waiting for it to seize up for 35 years! 2 weeks ago on our way to the Wasaga Beach car show my Wife called out on the 2 ways, "I have no oil pressure" and before I could reply the Son did and said "so what else is new, is it knockin' Mom".
 
dadsbee said:
Who knows what clearances are on most of our engines! I have no f'n idea on any of them. Bee was rebuilt in 1986 for $300, it runs 60 all day long, 30+ hot and sitting at a light. The Hemi in the 66 runs too high IMHO.. 90 cold... then 80 hot, but drops hot to 40 at a light. My Superbird has had pretty much zero oil pressure on 20W50 for 35 years... I switched to Penn Grade a couple years back and for the first time it showed 20 psi at speed. Still zilch at idle. Confirmed with a mechanical gauge... doesn't knock and I've been waiting for it to seize up for 35 years! 2 weeks ago on our way to the Wasaga Beach car show my Wife called out on the 2 ways, "I have no oil pressure" and before I could reply the Son did and said "so what else is new, is it knockin' Mom".
Click to expand...
Probably wouldn't run it if it was an actual airplane!?
Bunching up a car motor is one thing.. aero not so cool
 
I should clarify
We know that high oil pressure has no downsides,
Low oil pressure has all down sides. Gamble on that for your own ( financial?) Reasons.
 
RemCharger said:
We know that high oil pressure has no downsides,
Click to expand...
That is just not true. You have to put it in proper context. An example of high oil pressure is the added significant stress on the oil pump drive. For those that have experienced pump drive failure know what I am talking about.

Again - as long as you have oil film additional oil pressure and flow is not necessarily good. Only a tribologist can really give you a holistic picture of lubrication in an engine.
 
65CopCar said:
That is just not true. You have to put it in proper context. An example of high oil pressure is the added significant stress on the oil pump drive. For those that have experienced pump drive failure know what I am talking about.

Again - as long as you have oil film additional oil pressure and flow is not necessarily good. Only a tribologist can really give you a holistic picture of lubrication in an engine.
Click to expand...
Pump drive failure is usually connected to crap seizing up the pump. From my experiences. It would have to be a pretty soft drive for it to fail from turning a pump IMO
 
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