As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING AN INTERNAL INSPECTION OF THE ENGINE, WHEN THE PISTONS WERE REMOVED FROM THE CYLINDERS, EACH OF THE FACES OF THE TOP PISTON RINGS HAD STRIPS OF CHROME PLATING MISSING BETWEEN THE TOP AND THE BOTTOM OF THE RING AROUND APPROXIMATELY 70 PERCENT OF THE RING.