As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER TAKEOFF, PILOT HAD VIBRATION IN ENGINE. RETURNED TO AIRPORT, MAINTENANCE FOUND NR 2 CYLINDER CRACKED AT SPARK PLUG HOLE TO EXHAUST VALVE. CRACK APPROXIMATELY 5 INCHES LONG. CYLINDER REPLACED WITH NEW CONTINENTAL CYCLES AND RETURN TO SERVICE. (X)