As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING A ROUTINE COMPRESSION CHECK, THE NR 2 CYLINDER EXHAUST VALVE WAS FOUND LEAKING. AFTER THE CYLINDER WAS REMOVED, ALL CAM LIFTERS FOUND PITTED AND THE NR 5 CYLINDER INTAKE CAM LOBE FOUND SCOURED. THE ENGINE REMOVED FROM SERVICE. SUBMITTER SUGGESTED POSSIBLE CAUSE AS DEFECTIVE PARTS AND/OR ASSEMBLY PROCESS FROM THE FACTORY.