As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)THE OWNER REPORTED THAT #5 CYLINDER PISTON ROD MOVED ABNORMALLY AND THERE WAS A LOT OF METAL IN THE OIL FILTER. INTERNAL INSPECTION REVEALED THE ENGINE HAD LACKED OIL BECAUSE THE OIL PUMP DRIVE KEY (W OODRUFF KEY) HAD BROKEN. THE OIL PUMP AND THE ENGINE WERE ALMOST TOTAL WRITE OFFS DUE TO LACK OF LUBRICATION.