As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AT THE 50 HRS INSPECTION OF THE AIRCRAFT, DURING ENGINE CYLINDER COMPRESSION TEST, MADE CONTINENTAL ENGINE SB M91-6, AND THE TEST FAILED FOR CYLINDER NR 2 DUE TO A LEAK FOUND BETWEEN FINS AT CYLINDER HEAD. THE CYLINDER REPLACED AND AIRCRAFT RETURN TO SERVICE AFTER THE INSPECTION.