Judge387

Hi everyone. Ill try to make this as short as possible. Last summer i blew the engine in my 07 base. I picked up a 6.0 iron short block, never ran, forged internals... Again keeping this as short as possible and skipping many details.... Got it all together only reusing my old cyl heads but had them cleaned up and inspected. Fired up and ran it for a few hours in the garage, got it hot enough to burp the cooling system ect. Brought it to the shop to get tuned because i did change the cam and put a smaller pulley on the supercharger ect. I was there watching the car get tuned, the guy was just doing small rips making adjustments in small increments. (very impressed how much care he was taking of the car) Then he shuts the car off and explains to me the oil pressure is slowly falling, at idle i was down to 10 psi. I had a 10w30 dyno in there for brake in. we pull the car off the dyno and he checks it again after the car was cooled back down. Oil was in the low 20s He recommends putting in a thicker oil something in the 40 weight range. So i give the approval for that. They fire the car up. oil pressure in the high 20s almost 30 at idle, they let it idle to get hot., oil psi is holding around 25 psi. They get it back on the dyno and as the car gets up to temp again and he said oil pressure is falling.



Any ideas on where to start????? i have video of the car idling in my garage coolant temp around 200 deg. F and oil pressure is a touch above 40 psi.

That was before i installed the oil cooler..... The oil cooler was the last thing i did. I do not know what oil pressure was after the oil cooler though.... I know it was still good. But i dont know if it dropped at all after installing that. i did devolpe a small oil leak from the rear of the engine (starts dripping to the ground after a few min) thinking its the rear main but not sure.... I dont know if the oil cooler has anything to do with this or just poor timing.... Do you think the oil cooler can cause my oil pressure issues???? or should i be looking somewhere else?

Any ideas on where to start would be appreciated.

g23crawler

Not to be that guy but make sure you actually have enough oil in it.
Ls cam bearings are pretty tough, did you make sure to lube the cam well and not nick a bearing? Sounds stupid but I struggled with low oil pressure for months and all it was, was loose valley cover bolts.
Make sure the oil pick up tube isn't clogged and the o ring on the pump isn't pinched. Does the engine have new lifters? It could be a number of different things, do you know who built the engine? If they didn't use the correct size bearings you will never have good pressure.

Judge387

Judge387

Well unfortunately the sensor was reading correctly, no leaks around the sensor area. I pulled the engine out of the car. Verified that it was in fact the rear main seal that was leaking. Not nearly bad enough to cause my low oil pressure. I’ve been really doing a lot of research and I’m really starting to lean towards an issue with the cam bearings. I even called an engine builder in the area and told him I have a fresh rebuild and as it warms up oil pressure falls. His response was, that it sounds like you have to much play on the cam bearings. They do quite a few LS engines and they have seen it a few times. They have seen where “2nd design” bearings were used instead of “1st design”
I don’t know I’m hoping to get the engine torn down to a short block this weekend and inspect. What ever my issue is I’m really hoping it didn’t cause any serious damage