Please find attached evidence of cam follower failures in our IO540 at at 350 hours following a complete rebuild. The damage was caused by failure of the diamond coating on some cam followers. If we had been regularly sampling these defects could have been detected earlier and possibly the consequently piston damage could have been avoided. There was apparently a bad batch of cam followers distributed at the time our engine was first remanufactured.
After receiving oil analysis from you and before removing engine from aircraft we borescoped the camshaft and follower access via removing the oil filler tube top of engine. In the first image the cam lobe is ok but in others you can see the obvious preening and wear. Also note the photo of metal filings from washed oil filter element!
The moral of our story is don’t hesitate to sample, and don’t wait for engine hours to build up. We missed a warranty claim because because the problem was detected 3 years after remanufacture.
