As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) 5 CYLINDER ASSYS RECEIVED FOR REPAIR DUE TO LOW COMPRESSION. ABNORMALLY HIGH WEAR WAS FOUND INSIDE THE EXHAUST GUIDES. WEAR PATTERNS ON THE EXHAUST VALVES AND SEATS INDICATED THAT THEY WERE NOT PROPERLY ALIGNED CAUSING THE VALVE STEMS TO WEAR AGAINST THE GUIDES. (TC NR 20080124013)