As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE RUNNING ROUGH. COLD COMPRESSION CHECK SHOWED -0- COMPRESSION ON NR 6 CYLINDER. AIR LEAKING PAST EXHAUST VALVE. DISASSEMBLY REVEALED EXHAUST VALVE STUCK IN OPEN POSITION. EVIDENCE OF PISTON STICKING EXHAUST VALVE. THIS IS THE SECOND OCCURANCE OF THIS CONDITION ON THIS ENGINE. (K)