As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING A 100-HOUR INSPECTION AND FOLLOWING A CYLINDER COMPRESSION TEST, NR 3 CYLINDER COMPRESSION WAS FOUND TO BE 20 OVER 80 PSI. FURTHER INVESTIGATION REVEALED A CRACK IN THE PROXIMITY OF THE UPPER SPARK PLUG HOLE. THE CRACK RADIATED FROM THE TOP SPARK PLUG HOLE DOWN TOWARD THE EXHAUST PORT. CYLINDER WAS REMOVED.