As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE RECEIVED FOR O/H DUE TO HIGH METAL. DURING DISASSEMBLY, IT WAS DISCOVERED THAT A PIECE OF THE CHEEK ON THE CRANKSHAFT HAD BROKEN OFF ALLOWING THE COUNTERWEIGHT TO IMPACT CONNECTING RODS AND THE CRANKSHAFT. THE COUNTERWEIGHT PINS WERE UNDAMAGED. THE CRANKSHAFT COUNTERWEIGHT BUSHING WAS BROKEN.