Kohler K532

[Ron]

Kohler K532QS Spec 53180 in JD 400
120 lbs compression on one cylinder 35 on other. Removed head a noticed exhaust valve pretty thin. Seat looks ok. Cylinder wall has some scoring but not extremely bad. New valve 48 016 01-S is 80.00. Do you think replacing the exhaust valve will improve compression much? Will new valve have to be cut or just lapped in?

[creia]

Ron,
How about measuring the bore on the low compression cylinder and compare it to acceptable specs? Scoring is only part of the story. You could have a bore that is excessively worn, out of round, tapered, or ALL of the above. It could also be a broken ring. Of course, the best way to determine if the low compression is in the bore or valves is to perform a "leak down" test.
Michael

[KE4AVB]

Agree with creia on the leak down test.

Also depends how low the valve clearances are if valve replacement will resolve the problem. Only a couple ways to find out. I would try getting the valve clearance to spec and see if the compression comes up after reinstalling the head. Won't be prefect but would at least let you know if you're on the right track.

On valve replacement it depends how bad the seat is worn as to if the seat needs replacement too or just lapping but it sounds it will need replacing as they do round over. Just about as costly as the valve @ $51plus shipping . PN M43142 or 230265S. According the IPL I seen they are the same seat for intake and exhaust.