As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE O/H, THE ENGINE WAS TEST RUN 5 HOURS ON THE TEST STAND AND THEN DISASSEMBLED BECAUSE OF METAL IN OIL. AS PART OF INSPECTION NOTED THAT NR 4 EXHAUST CAM LOBE APPEARED TO BE WEARING ABNORMALLY. HAS A ROUGH SURFACE WITH SOME PITTING AND APPEARANCE OF METAL SMEARING. CAM FOLLOWER SHOWED BEGINNING OF DISTRESS BELIEVED TO BE CAUSED BY CAM. THE CAMSHAFT WAS NEW.