Too much oil pressure?

[JSeery]

As Ron stated it is like medium blasting the bearing surfaces! There are no positives to it that I am aware of and a lot of negatives. Short periods of time might not be that bad, but not sure why you would want it that high. If it were me I would switch to a lighter weight oil.

[Ronnie]

Yup^^^^ x2 Can't see any advantage of oil pressures that high.I am not aware of any benefits of having it high.If someone can state advantages of high oil pressure in a flathead lets hear them. Just sayin.

R

[Bored&Stroked]

For a street driven engine with normal crankshaft clearances, naturally aspirated horsepower levels and normal RPM ranges, I can see no advantage of higher pressures and heavy oils. I'd probably run 10w/40w in most engines - with good quality machine work, maybe even 5w/30w.

In a full-competition engine - especially a supercharged one, one will typically run much larger bearing clearances, much higher rod side clearances, heavier oil and a dry-sump system. We need the larger bearing clearances and heavy oil to account for crankshaft flex and load - and with the heavier oils, we'll have high pressure on the beginning of a run (like 110 - 120 psi at 2000 rpm), but by the end of the run, it will be closer to 70 - 80 lbs. (Note: this is at Bonneville).

[Drbrown]

Have 59AB with 80 lb pump; use 10w-30 oil; get 70 lbs cold any rpm; 40 to 50 lbs highway hot; 15 to 20 lbs idle hot.