As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE PERFORMING SB 388C, NR 6 CYLINDER EXHAUST VALVE TO GUIDE CLEARANCE WAS FOUND TO BE .010". BELOW ACCEPTABLE MINIMUM TOLERANCE OF .015". HAD 201 HOURS TIS SINCE SB 388C HAD PREVIOUSLY BEEN PERFORMED. VALVE DRIVEN OUT TO REMOVE IT FOR REAMING OF THE GUIDE. AFTER REAMING THE NEW CLEARANCE WAS FOUND TO BE .022".