Help Researching Compression Test Results

[FWBennett]

Hi Guys!
I'm still battling it out with Remanufactured dot Com. Of the 3 cylinders my mechanic tested #2-260psi #4-240psi #6-220psi. So they are arguing HOW he's testing them. Is there a definitive way to test compression - I've always just pulled one GP and spun the motor with the starter - put the GP back in then moved on to the next. ALSO - is there a definitive source that I can quote that says what the readings should be on a NA 6.2 that's just been rebuilt?
- thanks so much!

[john8662]

Assuming that the gauge being used is accurate I'd say that those results are TOO low. 275 is the bare minimum for a 6.2.

The procedure to be used is with a warm engine, pull one glow plug out, insert adaptor fully. Unplug the shut off solenoid on the injection pump to keep it from firing, then crank the engine over. You will want an assitant to help you, mainly to crank over the engine for you. You will start cranking the engine over, and count Six puffs, then quit cranking (or remember what the 6th puff is). Your compression results on a rebuilt engine should be 380-400psi.

Do them all if possible, but if you have confirmed that low of compression, sure bet the engine has something wrong with it.
I also want to add, that your starter and batteries should be in good health to get good readings, a slow cranking engine won't give you good results.

How is your blow-by with the engine running with the oil filler cap removed?

I don't know if there is a newly-rebuilt spec for compression on a 6.2. I would assume after the rings seat that you should have the best compression results that you're going to see on the engine throughout it's life. I would think that your ring would have seated by now.

[POINTERMAN]

I bought brand new compression gauge set and gauge wasn't accurate.So it might be good idea to get second gauge.

[EWC]

I would pull all the glow plugs out , this way you are only testing the one cylinder . If the other plugs are still in , the rest of the cylinders will be a drain on the starting system . Make sure the batteries are fully charged and the cables , starter , etc are in good condition . Slow cranking will give you lower results .

[FWBennett]

This is the 2nd motor - or 2nd try with the same motor. First motor tested low psi and would barely start or run, pulled it out and shipped it back - they said that 2 of the pre-combustian cups were rattling around loose in the head - they fixed it and shipped it back to me - I installed for the 2nd time. I've used it for about 200 miles before the mechanic tested the compression. With BOTH installations removing the oil filler cap makes the blow-by look like steam from and overheated radiator! This is the only "newly" rebuilt diesel I've had experience with. How long does it take for the rings to seat, if it's more than my 200mi then what kind of blow-by should I expect?
I'm thinkin' I've got a court case here and I'm looking for a definitive source for Compression Test Results that I can quote from. Basically my old motor that I sent back for a core on 1/11 that I haven't gotten paid for either - ran better than this re-built one!
- Thanks!