As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CYLINDER INTAKE SEAT NOT SEATED INTO MACHINED PORTION OF CYLINDER HEAD ALL THE WAY IN. UPON INSTALLATION AT FACTORY, NOT TAPPED IN COMPLETELY OR SEATED TO MACHINED HOLE. SUBMITTER STATES ALWAYS INSPECT NEW CYLINDERS FOR CORRECT SEATING OF VALVE SEAT INTO CYLINDERS.