What was found
PILOT REPORTED THE ENGINE DIED WHEN THE LT MAGNETO WAS TURNED OFF AND THE ENGINE WAS ROUGH RUNNING. MAINTENANCE CONFIRMED THE ISSUE, AND WHEN THE RT MAG WAS REMOVED, RATTLING COULD BE HEARD INSIDE. WHEN THE MAG WAS OPENED, THE BROKEN OFF END OF THE ROTOR, INCLUDING THE CAM AND ROTOR GEAR, FELL OUT. THE MAGNETO HAD BEEN IN SERVICE 1 MONTH SINCE INSTALL.