that does seem a little low. We run Valvoline 5-40 sinthetic in our motors that we would like to see a little more oil pressure.
one thing you could do is remove the wear plat on the oil pump and see if it is scared. while you have it off, check the end clearances with plastigage. this will make sure at least the oil pump is operating properly. If it is, you can always add a high volume oil pump this will help with the low pressure at idle problem.
Originally posted by victa1 My Buick 231 was built by an engine builder who has some "controversey" around him.
Brand new engine, at hot idle in gear I have 9-11 psi, and at crusing speed I get about 25-30 psi. Basically a little more than 10 psi per 1000 RPM. This seems too low,.... he stated he like to see 20 psi idle in gear.
I have spoke to him, and he strongly recommended straight 30W Shell Rotella T oil. ,,,,,,,... he is not fond of the Castrol 5-30W that is in the pan now, that low pressure scares me. Espcially for a new engine...................
We verify oil pressure on every motor we build before it leaves the shop. Cold, with a drill motor, they have numbers from 50-60 psi. In the car, cold is 70-80 psi, and at operating temp idle is normally 20-30 psi. This is with 10-30W premium oil.
A high volume pump is not a cure for low oil pressure and we never use them on any Buick motor unless supplied by the owner. If the stock cover passages are "blueprinted" and enlarged, this will provide ample pressure and FLOW.
There are many areas in the engine that affect oil pressure besides the oil pump/cover. Always hard to determine the exact cause of low oil pressure w/o looking inside. Guess you should stay in touch with the engine builder with this situation.