High Volume Oil Pump?
- Thread starter ncrobb
- Start date
If you have more internal clearance than the pump can keep up with, then you need more volume. Low idle oil pressure when using the correct weight oil for your normal ambient operating temperature is an indicator. If you've got 15 psi or more and the pressure comes up to a reasonable number, you're good. Hotter climates raise oil temp. Pressure drops as flow increases. Flow increase is fine as long as there is sufficient flow to keep up with the internal leaks. Thicker grade oil can help some. These are not just bearing clearance issues, but other internal leaks as well. Lifter to lifter bore, push rod orifices, rocker to shaft. Race motors have survived on 10 psi per 1000 rpm for years. Can you go lower? Yes but it can be risky for small gains. I would be comfortable with 45-50 on a street car that gets run hard a bit. I've run my racecar as low as 60 @7000. Also tried 45. Didnt break it but there was bearing to crank contact. Shells were polished. Bigger capacity is never a bad idea as long as there is sufficient ground clearance.
Doug
Doug
What he said!!
Really the answer to when you "need" one is, that depends.
Myself I went with one and a 6-qt pan on my current build, because the clearances were set on the loose side. My pressure is 55-60 when turning and about 20 at an 850rpm idle. BUT! I rest easy knowing I'm moving extra oil volume through all my leaks to see those pressures. The end of the line, being the pushrod ends, rockers, shafts etc all look great after 1000 hot miles. I may have come up a little short with a stock pump.
Really the answer to when you "need" one is, that depends.
Myself I went with one and a 6-qt pan on my current build, because the clearances were set on the loose side. My pressure is 55-60 when turning and about 20 at an 850rpm idle. BUT! I rest easy knowing I'm moving extra oil volume through all my leaks to see those pressures. The end of the line, being the pushrod ends, rockers, shafts etc all look great after 1000 hot miles. I may have come up a little short with a stock pump.
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BSB67
Well-Known Member
I'm not sure what you mean here. You are correct if you are saying that the increased volume has resulted in a more desirable pressure. However, you are incorrect if you are saying that you are getting more oil volume at the same pressure.
andyf
Well-Known Member
If it is a new engine then you need to talk to the engine builder about the clearances. If clearances are wider than stock then you might need a high volume pump. Or if you have pushrod oiling or EDM lifters or something else like that then you'll want a high volume pump. The spring is another variable. You can use a low pressure spring or the high pressure spring in a high volume pump. Just depends on what the engine needs.
What I meant was, the extra volume provided by the pump is sufficient to see that amount of pressure with the wider clearances. Maybe that makes more sense?
Obviously if the standard pump could show 20psi at the same RPM, the volume would be the same but I wasn't taking the chance this time..
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One more thing to consider is which type of bearing you're using. In my case I went with a hv/standard pressure because I used full groove mains vs. 180°. Had I used the half grooved, a standard volume pump would have been sufficient.
BSB67
Well-Known Member
I have full groove mains w/ 0.003" clearance, rods with 0.0025". Plus my #4 cam journal is grooved for full time oiling to my rockers. Standard pump.
Full groove main bearings is not the reason to use a high volume pump. The factory used full groove bearing with the standard pump and high pressure spring.
Full groove main bearings is not the reason to use a high volume pump. The factory used full groove bearing with the standard pump and high pressure spring.
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When I pulled my factory assembled bottom end apart it had half grooved mains. Check Clevites website to see the oil pressure loss when using 180° grooved bearings as the baseline vs. 360°.
BSB67
Well-Known Member
Right. But hemis had full goove with the same oil pump, different spring.
So does the chart that I cannot read say that my perfectly fine oil pressure with full groove mains at 0.003" and full time rocker oiling using my standard pump is my imagination?
I was referring to my 440 as an example. The chart (which I can clearly see by clicking on it) shows the potential loss in pressure with respect to increasing the grooving from 180° to 360°. It's an additional leak path. When I switched from a SV to a HV I saw a 10psi increase across the board. It's now right where I like it using the same SV spring.
BSB67
Well-Known Member
Sure, that makes perfect sense. And you now have the pressure that you like. Perfect. But to imply that you need a HV pump because you have full groove main bearings is incorrect.
Never said it's a requirement. It was a personal decision that improved the pressure readings to a more desirable level. Maybe Bob Renton can clarify things since I was discussing switching to the hv with him at that time. If someone wants to run a SV pump and is happy with what they have, fine. If not, it's always an option.
Never said it's a requirement. It was a personal decision that improved the pressure readings to a more desirable level. Maybe Bob Renton can clarify things since I was discussing switching to the hv with him at that time. If someone wants to run a SV pump and is happy with what they have, fine. If not, it's always an option.
Never said it's a requirement. It was a personal decision that improved the pressure readings to a more desirable level. Maybe Bob Renton can clarify things since I was discussing switching to the hv with him at that time. If someone wants to run a SV pump and is happy with what they have, fine. If not, it's always an option.
justcruisin
Well-Known Member
Good idea to use an HD intermediate shaft and a billet timing set when going to the HV pump. ( just my opinion).
Slap Stick
Well-Known Member
Didn't Ma MoPar use a HV pump on cop engines?
Seems I recall when I had a 72 Polara pursuit the oil light started flickering so I replaced the sender. No joy so I bought a new pump and they gave me a Melling HV/HP unit.
Seems I recall when I had a 72 Polara pursuit the oil light started flickering so I replaced the sender. No joy so I bought a new pump and they gave me a Melling HV/HP unit.
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