LS1 sat for a year wierd compression when checked
#1
LS1 sat for a year wierd compression when checked
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.
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.
Last edited by Littered; 08-04-2012 at 03:04 PM. Reason: Can't spell
#4
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.
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.
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#8
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!
Im not anywhere near a point to have it dropped in and didnt want to worry about it. I appreciate the help!