SheltonLS

Hello all, i have a rather odd problem that i would like opinions on.

I recently put a 2000 (i believe) LS1 into my 1997 nissan 240sx. The engine had burnt a piston with the previous owner, so i took it to a machine shop and had them re-do the shortblock with Mahle pistons and Scat rods. Stock crank polished and oil hols chamfered.

I put an SLP high volume oil pump in and was very careful about the o-ring on the pickup tube. I was very meticulous when finishing the longblock and the rest of the engine.

Upon startup the engine showed 20-25psi and would stay there until revving up to 4k or so, then jump instantly up to 40-45psi.

The gauge is a Stewart Warner maximum performance electric oil press. I returned it and got another identical gauge just in case it was faulty.

Same readings.

I thought "maybe these gauges are cheap for a reason" and drove it around like that.

I did probably 50miles of 1/2 to 2/3 throttle and 2/3 max rpm driving around to load the rings and properly seat them.

When i dumped the oil it came out as a golden slurry which i must assume is bearing material (extremely fine particles)

Does this sound like an improperly installed cam bearing or something?

I'd like to believe it's the shop and not me. Such an odd pressure right off the bat and shavings like that even with 20psi hot idle and 30-40psi cruising leads me to believe it's not a low oil pressure issue that's eating bearings, but a bearing installation issue that's causing both symptoms (oil hole in the bearing not lined up with the block maybe?)

Obviously i am going to tear it down to see (i would take it to them but at this point i don't trust them) what's wrong but was curious about opinions first. It's been such a long expensive process to finish this car and i just want to drive it. I'm so disgusted with this problem that i'll probably wait a week to start tearing into it to keep myself from breaking stuff.

BTW i don't trust the machine shop because when i picked up my engine and heads (had them check out the heads since i figured a burned piston could have flung aluminum between the exhaust valve and seat) they said "we didn't charge you to check out the heads" as if they had done me a favor. I think they might have put them in the parts washer but that's it.

This is the dead piston:



I bought a valvespring compressor and removed the exhaust valve from the dead hole to find this:


I can't believe it would have held pressure and definitely would have burned the valve pretty quick i think. I removed all the aluminum and lapped the valves until they were perfect again before re-installing.

FML sometimes i hate cars.

Ideas? Course of action?

Old Geezer

iTrader: (3)

Course of action: Even if I didn't trust them, I would take it back to the shop and ask them to determine what happened. [While I am watching]. SAVE an oil sample!
Force the issue, and take action if warranted. If they messed it up, let them either at least refund the cost, and you go away. Or, if they want to get nasty...Let them explain it to your lawyer, in ft of a judge....

My gut is the oil pump... 20-25psi at cold start is waay low, IMO.

SheltonLS

I'm thinking about doing just that.

I agree that 20psi is low, but it's a brand new oil pump. Also, 20psi at 800rpm should not make a golden slurry.

KCS

iTrader: (20)

Pull the engine and take it back. Let them take a look while you're there and discuss the options. Take pictures and post them if you want a second opinion.