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Oil Pressure
Posted by: bmarsh52 ()
Date: June 30, 2022 06:26PM

Is it possible to have too high oil pressure and could that cause oil leaks? What is considered normal cold and operating temperature oil pressure? Engine has a Pro Flo high volume oil pressure pump. Cold pressure is over 60 when cold and in the 30's when warm. 10W 30 Rotella oil.

Thanks

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Re: Oil Pressure
Posted by: pvholgado ()
Date: June 30, 2022 06:43PM

What does over 60 mean? My newly rebuilt motor shows 50-55psi on start up and 30 or so warm.... I believe this to be normal.There is a bypass valve and spring that limits the upper range- I don't have any idea what is a normal bypass pressure.

"A sign of great intelligence is being able to say 'I don't know'"
1966 Corsa Turbo Coupe
Located 25 miles East of Rochester, NY

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Re: Oil Pressure
Posted by: cnicol ()
Date: June 30, 2022 06:55PM

Yes, it's possible to have too much oil pressure. The common failure point is the oil filter gasket and that's a messy one!

I look for 40-45 cold and 35 max when warm. The basic concept is 10 PSI per 1000 RPM with the oil pressure regulator bypassing to hold that pressure and return excess to the oil pan.

Hot Rod magazine, as noted and repeated by Bob Helt, found no advantage to high-pressure oil pumps and found they actually raised the oil temperature while providing no benefit except in cases of "end of life", excessive engine wear.

My 215 Olds had similar high oil pressure when cold so I switched to 5W30 oil and that cured the issue.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: Oil Pressure
Posted by: dryenko ()
Date: June 30, 2022 06:56PM

Stock bypass is set in the range of 45 psi.
This applies hot or cold.
For racing, with our Corvair engines, the rule of 10 psi for every 1000 rpm has been used.
So for 6000 rpm in a track application, 60 psi is desirable , at that rpm.
YOMV
BC

Bob C aka Dryenko
Dobson, NC 27017

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Re: Oil Pressure
Posted by: Frank DuVal ()
Date: June 30, 2022 07:00PM

If the pressure is TOO HIGH the oil filter will balloon and then the gasket shoots out! Very interesting to watch.eye popping smiley

This was caused by the oil pressure regulator piston being stuck in its bore. I removed it, cleaned it and it ran fine. You can take yours out and clean it if it was not cleaned during the rebuild.

You running straight 50 or something else really really thick?

Frank DuVal

Fredericksburg, VA



Edited 1 time(s). Last edit at 06/30/2022 07:01PM by Frank DuVal.

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Re: Oil Pressure
Posted by: Wagon Master ()
Date: June 30, 2022 07:34PM

dryenko Wrote:
-------------------------------------------------------
> Stock bypass is set in the range of 45 psi.
> This applies hot or cold.
> For racing, with our Corvair engines, the rule of 10 psi for every 1000 rpm has been used.
> So for 6000 rpm in a track application, 60 psi is desirable , at that rpm.
> YOMV
> BC


So that being said, with the bypass set at approx. 45 p.s.i. how are you achieving the 60 p.s.i. required for 6,000 r.p.m.?

Been aircooled since 1973
Northwest Ohio 45840

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Re: Oil Pressure
Posted by: Frank DuVal ()
Date: June 30, 2022 08:48PM

Bypass spring can be shimmed or replaced to change the pressure relief point.

Frank DuVal

Fredericksburg, VA

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Re: Oil Pressure
Posted by: bmarsh52 ()
Date: July 01, 2022 04:53AM

Frank,

Current oil is 10W30 Rotella. No heavy weight oil.

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Re: Oil Pressure
Posted by: red monza ()
Date: July 01, 2022 05:05AM

After building the 283 I put in my 49 Fleetline, I was bragging to my super smart mechanic about the high oil pressure. On cold start up it goes to 100psi and after warming up stayed high at about 70psi. He sat me down and said "NOT GOOD, it will wear your bearings much faster than one with normal or low oil pressure. He explained it to me by telling me about water in a fast moving stream with a narrow passage way. The rocks will be smooth and rounded in that area with age. I remember taking the oil pan off and we made a change to the oil pump. It still goes to 100 on start up but after warming up, at 2,000rpm (55mph) it runs about 55psi with 10-30 Havoline conventional oil. Ten years on the road it only has 8,000 miles since building the car.

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