As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
VERY LOW COMPRESSION NOTED IN THE NR 3 CYL ON RT ENGINE DURING ANNUAL INSP. THE CYL REMOVED AND INSPECTED. THE EXHAUST VALVE GUIDE WAS WORN TO THE POINT WHERE THE VALVE COULD NOT SEAT PROPERLY. CYL REQUIRED BOTH VALVES AND VALVE GUIDES TO BE REPLACED. RE-ASSEMBLED, COMPRESSION TEST GOOD. SUBMITTER STATED IT APPEARED THE MATERIAL USED IN THE VALVE GUIDES IS TOO SOFT AND SUBJECT TO PREMATURE WEAR. IT IS SUGGESTED THE MFG REVIEW ALLOY IN THEIR VALVE GUIDES, AND MAKE ADJUSTMENTS AS NEEDED. (X)