Lemme do a run down on my oil pressure, mind you this is a brand new rebuild with some mods and the oil pump is Melling M155 standard pres, standard volume with the GM white spring and stock pan.

When I first start its about 70 psi until it warms up.

When warm it is about 40psi at idle.

When under big load it will go up to like 60 but sometimes the gauge will flutter as the RPM's rise and it will go to like 40psi.

What do you guys think this could be. I am starting to think the sender could be wrong, I have never seen a motor make less oil pressure under a load before, and the fact that it seems to flutter around.

Lemme know what you guys think,
James

BTW- I ran ND 30wght for the first 10 mins, then went to Castrol 10-40 dino oil for the first 500. I am at about 20-30 of that 500miles right now.

-James

 

Sounds like cavitation to me. You got a windage tray in there? Turbulence in the oil and/or running out of oil are both possibilities. I've seen this happen on lt1s many times with similar setups. Fine pressure, WOT, up, up, up, flutters a little above 40 psi.

 

I'll second that, buddy of mine had a similer problem after a rebuild, turned out to be a lack of windage tray.

 

I built it myself, and the stock windage tray is definitly in there. Do you guys think adding a 1/2 quart would help anything?

I havent gave it 100% yet because of this. But I'd think 40+psi is okay under throttle?

Also, is there any way to put a aftermarket pan/windage tray/oil pump on with the motor in the car?