Compression Test

Numbers can vary between gauges also. I have seen up to a 10lb. difference between
gauges. The important thing is difference between cylinders.
 
I think 10 percent between cylinders is ok. But in your case it means very little. You need to put some miles and time on it. Before you check it. Then check it hot after a drive with the throttle held wide open. But if it is running ok and it is not missing why worry about it.

The only reason to put oil in the cylinders for a test is to see if the rings or valves are bad.If it raise the compression when the oil is used, then the rings are bad.
 
George Miller said:
I think 10 percent between cylinders is ok. But in your case it means very little. You need to put some miles and time on it. Before you check it. Then check it hot after a drive with the throttle held wide open. But if it is running ok and it is not missing why worry about it.
Click to expand...

agree,,,, thats right on
 
Dodge said:
Numbers can vary between gauges also. I have seen up to a 10lb. difference between
gauges. The important thing is difference between cylinders.
Click to expand...
Yes, Dodge,
Gauges DO VARY. I always let one go for at least 10 strokes or until gauge no longer rises. If one tests low, check it several times. Sometimes you might get a little carbon stuck under a valve, from removing the plugs. I always check valve lash BEFORE removing the plugs, for the same possible carbon problem.
Bill W.
 
If you find that the rings may be stuck you can fill the cylinders with Lacquer thinner and let it sit for several days. Make sure to drain oil and only turn engine over by hand with plugs out until all is drained.
 
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