PPRuNe Forums - View Single Post - Engine specs for dummies anyone?
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Old 29th Mar 2009, 19:53
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SNS3Guppy
 
Join Date: Oct 2005
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Compression values are highly overrated, and given far too much importance by the average layman.

The chief value of performing a compression test isn't the compression numbers, but the ability to identify the leak location, if indeed there's a leak. Pressurize the cylinder, listen for the leak (exhaust, crankcase, intake).

Compression values go up and down with the test unit in use, the person performing the test, the temperature of the engine, and vary from time to time when the tests are performed. It's not uncommon for test values to go up since the last time the test was performed. The actual values identified during a cmpression test...aren't really very significant unless a substantial decrease occurs.
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