phat82

I would suggest blueprinting the oil pump. Even name brand pumps can be out a specifications. If the housing isn't machined square then the rotor to housing clearances will be off. The Rotor-to-Housing clearance should be between 0.002" and 0.0025", plus the clearance of the two rotors should be fairly close to the same, i.e. if the front measures 0.0020", then the rear should be approximately 0.0022". Also, you should make sure that the gears are pinned to the shafts not pressed on.

Matt Gruber

there is a pipe plug used under #5 main bearing.
if it is missing i have read that oil pressure will be awful.
it is often removed to clean the passages.
if it has 50psi at5000 i would find something else to worry about, and i would switch to 20w50 oil.

R1234

I pulled the oil filter installed a new GM oil filter adapter/relief spring and got the same oil pressure readings. Let motor get up to operating temperature
of 205. Revved to to 4500 rpm and oil pressure only went to 35 .lbs
I guess I'll be pulling the oil pan next and checking the pump.

Clink69

Just another note. Why is your operating temp 205? seems quite high to me. I wouldn't want that above 180 and I run mine at 160 with my new 383.

My oil pressure was the opposite of yours. Start up cold and it pegs to 75 lbs after warm up it idles at 35 and revs to 75 or so. IMHO your pressure is WAY too low for a new engine. GM specs tend to allow low oil pressure as the norm but I think you will find that most people believe their specs are low.:flag