As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CYLINDER INSTALLATION ATTEMPTING TO TORQUE ROCKER SHAFT HOLD-DOWN SCREWS RESULTED IN 2 SCREWS STRIPPING BEFORE THE MINIMUM TORQUE OF 180 INCH/POUND WAS REACHED. THIS IS THE 2ND OCCURRENCE ON THIS ENGINE. BOTH TIMES THE CORRECTIVE ACTION WAS REPLACING SCREWS AND CLEANING THREADS IN ROCKER SHAFT. COULD NOT DETERMINE IF THREADS IN SHAFT ARE STRIPPING OR IF SCREWS ARE DEFECTIVE.