I just finished lapping-in-place a leaking exhaust valve on a Lyc O-320. The compression went from ~40:80 to 76:80. Borescoping the valve and seat had shown the seat to be rough and pitted (1900 hours), but now it's smooth.
My question: is it possible to overdo this treatment? Specifically, are Lyc valve seats through-hardened, or can one lap through a hardened surface into a softer material - which would presumably wear quickly post-procedure?
My question: is it possible to overdo this treatment? Specifically, are Lyc valve seats through-hardened, or can one lap through a hardened surface into a softer material - which would presumably wear quickly post-procedure?