Well, I'm using a Matco dial back, I figuredit was a good light, traded a chainsaw fer it, got it from a mechanic pal o mine...Not 100% sure that my damper is "dead on" TDC.... been driving that mill for 12 years, some years daily.. Hmmm Rob, don't know if Ya remember, but remember the Detonation scare? Could the thing have spun, showing Less ?