What was found
REPETITIVE OIL ANALYSIS REVEALED HIGH WEAR METAL LEVELS FROM CYLINDER AREA WEAR (PISTON, RINGS, LINER). REMOVED AND REPLACED CYLINDERS WITH FACTORY NEW CYLINDER KITS. WHILE CYLINDERS WERE REMOVED, PISTON COOLING OIL JETS WERE REMOVED AND TESTED. FIVE OUT OF 6 FAILED INITIAL TEST. AFTER CLEANING ALL SIX, 4 WERE RETURNED TO SERVICE AND 2 WERE REPLACED WITH NEW. THIS IS THE SECOND AIRCRAFT/ENGINE COMBINATION OCCURRENCE. SUBMITTER SUSPECTED CLOGGED OIL JETS NOT PROPERLY COOLING/LUBRICATING PISTONS CAUSING DISTORTION RESULTING IN WEAR.