I've used my compression tester in the past with no ill effects to it.
However, it really is not accurate enough. You need a gauge that will
measure 0-100 lbs. or less. Professional tool companies like "Mac" or
"Snap-On" should have them. If you see one of their trucks, stop them, they
will be more than happy to sell you a tool. Their tools are very nice, but
pricey. Also just look around at flea markets and garage sales, discount
tool dealers, etc.

yug