As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAGNETO APPARENTLY SUFFERED A STOPPAGE CONDITION DUE TO UNKNOWN FAILURE OF IMPULSE COUPLING. DISINTEGRATED INTO SEVERAL PIECES. PARTS FOUND IN FILTER AND PRESSURE RELIEF VALVE. PROBLEM NOTED AT OIL CHANGE AND PILOT REPORTED GRIP OF LOW OIL PRESSURE. MAGNETO HAD BEEN CHANGED PREVIOUSLY AT DIFFERENT LOCATION.