As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) WHILE CHANGING AN INTAKE PUSH ROD TO COMPLY WITH LYCOMING 400 HOUR VALVE TRAIN INSPECTION (TAPPET CLEARANCE), THE PUSH ROD WAS FOUND TO HAVE A O.020 INCH DEEP SCORE AROUND THE CIRCUMFERENCE, A HALF INCH FROM THE TOP. CLOSER INSPECTION FOUND THE SCORING CAUSED BY AN EXHAUST ROCKER INSTALLED IN THE INTAKE POSITION. THE INTAKE ROCKER PART NUMBER HAD BEEN ETCHED ON IT.