Littered

Been lurking here for a while gathering info for my project. Love the site.

I recently picked up an 2001 ls1 and have been getting it ready to drop in. When I purchased the motor last week I was told it came out of a running car that was wrecked in the rear. I did a vin check and can see that it was salvaged almost one year ago next month. So it sat for a while drained of oil.

I did a compression check this morning after adding new oil and filter, and pouring some inside of the valve covers. With it still on the engine stand I also turned it over a few times by hand. My first compression check showed:

1) 120. 2) 180
3) 210. 4) 210
5) 210. 6) 60
7) 210. 8) 60

So I added a little oil to the cylinders and turned it over a few times and then let it sit for about 4 hours. When I rechecked it I got:

1) 150 2) 175
3) 195 4) 180
5) 190 6) 180
7) 180 8) 170

I checked the compression per the service manual, 4 cranks per cylinder. I recheked it 2 hours later with the same results as above.

My motor is still covered by the yards warranty and I wont be getting it running for a few more months, but I am at the stage where I am getting parts and having the ECU and wiring harness done. So Im not sure if the low compression was a result of sitting and being dry or I should take this one back and get another one?

I am very new to these motors so please excuse my lack of knowledge. I appreciate any insight you can provide.

Littered

Does anyone have experience with a motor that sat dry for a while?

chevymec

iTrader: (19)

Sounds like the rings were sticking.

Littered

Thank you for the input

I have checked a few more times since then and I'm getting a constant compression variation of 12% across all cylinders. Also I am only getting a difference of 6% at most between a dry wet compression check. Keep in mind this is on a cold motor.

bww3588

iTrader: (49)

If the motor is not in the car, how were you cranking the engine? By hand? Or did you have a starter hooked up?

bww3588

iTrader: (49)

The engine should also be a operating temp for a more accurate compression test since the pistons are cam ground meaning the clearances aren't where they should be cold.

redtail2426

iTrader: (10)

you wont get very accurate results turning it over by hand,and with it not being warmed up.I would drop it in and fire it up

Littered

I had it on a stand with a starter and battery hooked up. I ended up trading for a 20,000 fewer miles motor. I dont think the pressure should be 60psi even when cold. Especially when all other cylinders were hitting 180s.

Im not anywhere near a point to have it dropped in and didnt want to worry about it. I appreciate the help!