any chemists here?

The prep would have to be bad to come off in sheets. Sounds like he's just trying to get one over on you Steve.

It was just a good amount of overspray on the valvetrain. I didn't catch it before my employee buttoned up the valve cover. It was a reseal/paint job on a TIRED motor. There must have been 1/4" of gunk on his intake valves and about 1 1/4" inch of slack in the timing chain.