As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CYLINDER WAS INSTALLED USING NEW RINGS AND GASKET SET FROM ECI ALSO. REMOVED CYLINDER DUE TO LOW COMPRESSION AND EXHAUST STAINS AROUND THE EXHAUST AREA. FOUND THAT HEAD WAS CRACKED BETWEEN BOTH SPARK PLUG HOLES AND BY THE EXHAUST SEAT, WHICH IN RETURN BURNED A HOLE NEXT THE EXHAUST FLANGE.