As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PROBLEMS ENCOUNTERED WITH SUPERIOR CYLINDERS, B OR B SERIES. NR 4 CYLINDER HAD STUCK EXHAUST VALVE AND BENT PUSH ROD. NR 1 AND NR 2 CYLINDERS HAD CRACKS EXTENDING FROM THE SPARK PLUG HOLE TO THE FIN AREA LEFT OF THE SPARK PLUG HOLE TO THE FIN AREA LEFT OF THE SPARK PLUG HOLE (WHEN FACING THE CYLINDER). FIELD INFORMATION INDICATES THIS IS A PROBLEM WITH B SERIES CYLINDERS AND NOT THE D SERIES.