cmayna: 235 compression should be in the range of 130/135 PSI for a standard 8.25 CR engine. The engine must be warmed to operating temp to get an accurate test.
Make sure you turn engine over at least 4 compression strokes on each cylinder to obtain a true reading.
Check and record compression for each cylinder.
Any variations between highest and lowest reading cylinders should be less than 20 PSI.
Place oil in plug hole of any suspect/low cylinder and re-test. After re-test if:
Side by side low cylinders means headgasket leakage and/or possible block (crack)troubles.
If compression does come up some, but does not reach "normal" level, this indicates ring troubles, either worn, broken, or sticking.
If compression does not come up after adding oil this usually indicates valve troubles, either burned, broken, bent, sticking.
Also can perform cylinder leakdown test, or vacuum test in conjunction with compression test on any low or suspect cylinders to verify troubles before you proceed with teardown and inspection for problems/corrections. Have Fun!
Think Chevy!
:rolleyes:
