[CREWZIN]

Found this on PT Do-it-Yourself.net .......

Compression should not be less than 689 kPa (100 psi) and not vary more than 25 percent from cylinder to cylinder. If one or more cylinders have abnormally low compression pressures, the compression test should be repeated. If the same cylinder or cylinders repeat an abnormally low reading on the second compression test, it could indicate the existence of a problem in the cylinder in question.

Low compression in one cylinder usually indicates a bad exhaust valve. Low compression in two adjacent cylinders typically means a bad head gasket. Low compression in all cylinders usually indicates that the rings and cylinders are worn and the engine needs to be overhauled.

If compression is low in one or more cylinders, you can isolate the problem to the valves or rings by squirting a little 30 weight motor oil into the cylinder through the spark plug hole and repeating the compression test. The oil temporarily seals the rings. If the compression readings are higher the second time around, it means the rings and/or cylinder is worn. No change in the compression readings would tell you the cylinder has a bad valve.