As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER LANDING PILOT WAS TAXIING FOR SHUTDOWN WHEN HE HEARD A BANKING NOISE AND REAR ENGINE ROUGHNESS. INSPECTION REVEALED A DENT IN VALVE COVER. COVER REMOVED AND FOUND BOTH ROCKER SHAFT HOLD DOWN STUDS SHEARED. IT HAS BEEN NOTED BEFORE ON OTHER AIRCRAFT THAT ROCKER SHAFT HOLD DOWN NUTS HAVE BEEN STRIPING EASILY EVEN WITH TELEDYNE CONTINENTAL NEW ROCKER SHAFT HOLD DOWN NUTS TORQUE VALVES. . .