As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 4 CYLINDER EXHAUST LIFTER SPALLED SEVERELY CAUSING DAMAGE TO THE CAMSHAFT LOBE. ALL OTHER LIFTERS LOOKED GOOD. ENGINE WAS FACTORY OVERHAULED 7/97. FOUND METAL IN SCREEN AND FILTER LEADING TO INVESTIGATION WHICH TURNED UP THIS PROBLEM.