As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED ENGINE SHUDDERED IN FLIGHT AND THEN STOPPED SHORTLY AFTER. THE AIRCRAFT LANDED WITHOUT INCIDENT. INITIAL INSPECTION REVEALED AN ENGINE CASE PENETRATION AT THE TOP REAR OF THE CASE AT THE NR 1 CYLINDER IN THE AREA UNDER LEFT MAGNETO, AND THE MAGNETO FLANGE BROKEN. THE ENGINE IS IN PROCESS OF BEING REPLACED, FURTHER DETAILS TO BE SUPPLIED UPON TEARDOWN INSPECTION.