8.5:1, 408 compression test. What readings should I expect?
12-12-2008, 10:30 PM
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8.5:1, 408 compression test. What readings should I expect? I posted this in the LS1 section but thought I'd post a link here since it's on a forged low compression motor. It's a 408 on 8.5:1 and have started seeing more blowby lately. I've done the leak down which showed near identical #'s across the cylinders and so I'm now gonna do a compression test to see if it shows anything.
What #'s should I see for good compression and what would suggest needing new rings?
What #'s should I see for good compression and what would suggest needing new rings?
12-13-2008, 11:39 AM
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I got 160-162 and #8 came up w/ a 158. Any thoughts/comments on these #'s? If it makes a difference, this is the cam I run.
Cam Motion 236/232 dur. @.50" .588/.574 114LSA 110ICL
Leak-down numbers were consistent too.
Cam Motion 236/232 dur. @.50" .588/.574 114LSA 110ICL
Leak-down numbers were consistent too.
12-13-2008, 12:28 PM
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They should all be within 3%-5% of each other.
Seems a bit low to me for a fresh motor, but I'm kinda used to only checking my NA race motor, which had over 240 in every cylinder. My 1994 GMC Sonoma with 240K on it when I bought it had around 150 in each.
Seems a bit low to me for a fresh motor, but I'm kinda used to only checking my NA race motor, which had over 240 in every cylinder. My 1994 GMC Sonoma with 240K on it when I bought it had around 150 in each.
