As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT THE AIRCRAFT OWNER/OPERATOR NOTICED A DRONING VIBRATION AT CRUISE. UPON LANDING, ALL CYLINDERS WERE INSPECTED AND BORE-SCOPED. MOVED PROPELLER BACK AND FORTH AND HEARD A CLUNKING NOISE, NARROWED DOWN TO CYLINDER #2 PISTON SHOWING SIGNS OF EXCESSIVE MOVEMENT INSIDE CYLINDER BORE. ENGINE WAS DIFFICULT TO TURN OVER BY HAND. REMOVED CYLINDER #2 AND FOUND CONNECTING ROD STICKING STRAIGHT OUT AND NOT FALLING DOWNWARD UNDER THE WEIGHT OF THE PISTON. REMOVED WRIST PIN AND FOUND ABNORMAL WEAR ON THE CONNECTING ROD WRIST PIN BUSHING AND WRIST PIN. FOUND CONNECTING ROD VERY HARD TO ROTATE ON THE CRANKSHAFT.