Is it possible to have too much oil pressure? What is too much? Side effects of too much?

all things are relevant mine is 100 psi and im happy with it

10 lbs per 1000 rpm is a good rule of thumb

Too much oil pressure costs a little horsepower and may put too much oil up on top of motor.

Too little oil pressure gets ugly quickly.

My 454 SBC ran with 50 Lbs of pressure at 7600 RPM for many years with 18" inches of vacuum. Some people use heavier oil to get higher pressure be aware that heavier oil does not drain back into oil pan as quickly. By the end of the run most of the oil was up on top of motor and if I hit brakes hard lost oil pressure. Thinner oil resolved that issue.

If you're running your ignition through your distributor, higher pressures can exacerbate spark scatter.

quote:

Originally posted by racerdude2054:
Is it possible to have too much oil pressure? What is too much? Side effects of too much?

If the pressure is big because of too tight of bearing clearance then it probably won’t stay together long.

quote:

Originally posted by racerdude2054:
Is it possible to have too much oil pressure? What is too much? Side effects of too much?

TOO much could burst an oil filter (extreme). TOO much can stay in the pressure regulator range too much. TOO much can wear out the distributor gear prematurely. There are probably other things it can do but there are just a few.

Excess pressure can only get you HP drag, hot oil, excess wear and tear, and broken small base circle SBC cams.
Pressure has little to do with the volume delivered.
I keep my stuff 70 p.s.i. or less cold, 60-ish hot at 6000 RPMs, 10w30 oil.

Edit: Speaking only about basic wet sump systems in N/A applications.

This message has been edited. Last edited by: Goob,

how much psi is too much ... certainly it can have too much. parasitic drag, cavitation, washing rings down are some issues. what is really important is this a problem from a new build or has the issue came up over time. if reading off racepak verify with a known good gauge too.

100psi myself no problems. External oil pump

As others noted, there are some potential drawbacks to "too much" oil pressure, but what that number might be is subject to the build, the oil being used, and the preference of the owner/driver.

Somewhat unrelated story: Years ago, back when blown engines (as in "she done blowed-up") were a fairly common occurrence in NASCAR racing, some teams pushed their oil pressures way up, (well over 100 PSI), and they started seeing more bearing wear and even some failures, that showed actual erosion of the bearing material due to the excessive pressure. (Belt-driven Dry Sump systems). Those were 500 mile races, so obviously not a concern with what we do... (Unless you go 2,000 passes between freshen-ups and go wild on the PSI).

Too much oil pressure is also hell on the shaft and distributor gear.

Years ago, either the Engineering Department at TRW or Clevite did a study of oil pressure and bearing life. This was done with the best bearing materials at the time. The conclusion was that there was a down side (Power loss) to excessive oil pressure as well as the resulting pattern it created across the face of the bearing surface. I remember the result from that study, (which I believe was done on a small block Chevy), concluded that 10 pounds per thousand RPM produced the overall best result.

I don't know of any other studies and there may be many, but this was the conclusion of the ones conducted by TRW and Clevite.

Janeen (Actually Janine) Sine (Presently the Co-Owner of Bullet Cams) was in charge of the Engineering Department at TRW, perhaps she remembers that study.

Bob
(Sorry about mis-spelling your first name Janine)

This message has been edited. Last edited by: RPROGAS,

The 10 p.s.i. per thousand "standard" was to overcome centrifugal forces in the crankshaft oil passages.

I would love to have seen the bearing pattern they had from to high pressure.