Engine Compression (1 Viewer)

[ClemsonCruiser]

A couple of days ago I posted regarding rebuilding or reringing my engine, because of low engine compression and burning oil. I went to auto zone this morning and bought an engine compression test kit. Because the last time the compression was tested in my engine was december and the mechanic who did it said the range was 105-115. So I did the test today my self and got an average after 3 runs of 143, 125, 115, 130, 130, 145, and the drop in the #2 and #3 cylynders is bad??? This is quite different from what the mechanic told me 3 months ago. I have added engine restorer, could this make the compression change that much??? Also with the numbers I got today what does it mean for my engine can any diagnosis be made. My engine only has 52000 miles on it and it is a 77 2F if that helps. Your thoughts are appreciated

Thanks
JP

 

[Degnol]

You might try a wet test on 2 and 3. Squirt a couple of squirts of motor oil in the cyl and try again. If the compression takes a jump, you've got ring problems. If no effect then you have valve problems.
Hope for the latter. That way you may just need a head job.
Seriously, no pun intended.
Ed

 

[IDave]

Looks like you probably have good compression overall. "Wet" test all the cylinders with an ounce or two of engine oil and post us the results you get with that. (Snuck one in on me, Ed)

Some of your variation may be improper valve lash, which an hour or two playing with the clearances could straighten out. I doubt that the engine restore (stuff I like, by the way) fixed your compression that much. I would suspect the original data.