As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON DISASSEMBLY OF ENGINE FOR OVERHAUL, A SETSCREW FROM THE PROPELLER IDLER GEAR SHAFT WAS DISCOVERED SLIGHTLY EMBEDDED INTO THE INSIDE OF THE REAR-LT SIDE OF THE CRANKCASE. SETSCREW WAS PROBABLY IMPROPERLY PEENED FOR RETENTION IAW OVERHAUL MANUAL SEC 7-74, AT THE PREVIOUS OVERHAUL AND MIGRATED THROUGH THE ENGINE TO ITS FINAL RESTING PLACE. (K)