As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE OIL FILTER CONTAINED MANY FINE FLAKES OF FERROUS MATERIAL. PREVIOUS SOAP SAMPLE SHOWED ELEVATED IRON CONTENT. VALVE LIFT OF THE NR 3 AND NR 4 INTAKE VALVES WAS APPROXIMATELY .15 INCH LESS THAN THAT OF VALVES IN THE OTHER CYLINDERS. REMOVING THE NR 3 CYLINDER ALLOWED A VIEW OF SPALLED TAPPETS FOR THE NR 3 AND NR 4 INTAKE VALVES AND LOSS OF MATERIAL FROM THE TOE OF THEIR SHARED CAM LOBE. (M)