Checking Compession

[kenh1010]

I would like to check the compression on a motor<br />but unable to warm the motor up. How can I expect<br />the readings to vary when checking cold? <br />Could they all be low, all high, or can they<br />vary among cylinders and then read normal after<br />warming up? Thanks

 

[JB]

Re: Checking Compession

Hi, Ken.<br /><br />Usually, cold compression readings will be lower than warm, and likely to vary more than warm readings.<br /><br />Example: OMC V4, 1980. Cold readings were 120,122,118,125. Warm readings were 125,124,125,126. Either set indicates a good engine, but the warm set told me just how good it was.<br /><br />Red sky at night. . .<br />JB

 

[kenh1010]

Re: Checking Compession

Thanks J.B.<br />Nothing better than a real life example.

 

[novacane]

Re: Checking Compession

variation from cylinder to cylinder is what i look for say 120 122 100 121 lets see witch one would be greif? its a no brainer all need to be with in 10% of 1 another good luck