Analyze my compression test please!
I own an Ap1 with 169000km on it (105kish miles) and I've been debating between going turbo, or selling the car and getting a lower mileage one and then going turbo.
I did a compression test, and these were the results: Back to front Cylinder 1: 260-260-260 Cylinder 2: 240-240-240 Cylinder 3: 240-245-245 Cylinder 4: 245-250-245 I've had a valve adjustment done within the last 5000kms What's up with Cylinder 1? Should I be concerned, or just run something through the car to try and clean the cylinder of any excess carbon buildup? Cylinder 1's plug had a little more carbon than the others... Thanks guys |
My manual says nominal compression should be 228 psi with a maximum variation between cylinders of 28 psi. Hope this helps.
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I would be happy about it and go for a long drive
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Do it again, start with cylinder 4. see if your numbers change. high compression usually means excessive oil in the rings, or fauly reading. Carbon COULD cause it, but that is highly unlikely.
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did it 4 times, exactly 260 each time
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If the car runs and sounds fine, it probably is. I wouldn't worry about it.
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The fact that it's consistent is good, and while your variances aren't "perfect", they're within OEM specs. Cyl 1 reading high is weird, but things could be worse.
Drive the car a bit and do the test again. Maybe an exhaust valve of Cylinder #1 isn't opening all the way? It could also be oil, or carbon buildup. I'd bet it's carbon buildup. |
Originally Posted by vividracing.com
(Post 20840632)
The fact that it's consistent is good, and while your variances aren't "perfect", they're within OEM specs. Cyl 1 reading high is weird, but things could be worse.
Drive the car a bit and do the test again. Maybe an exhaust valve of Cylinder #1 isn't opening all the way? It could also be oil, or carbon buildup. I'd bet it's carbon buildup. Car runs perfectly btw guys. |
There's probably a reason for it. Fix that reason, and eventually the carbon will get burned off. You could try a steam cleaning or sea foam, but I've always been wary of putting fluids other than gasoline in my engine. Sea Foam would be my choice between the two.
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