As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE HAD LOW COMPRESSION AT INSPECTION. MECHANIC FOUND BURNED EXHAUST VALVE. THE CYLINDER WAS DISASSEMBLED AND THE EXHAUST GUIDE WAS FOUND TO BE WORN BEYOND LIMITS. GUIDE WAS WORN TO .5080", MAX WEAR IS .5025". THIS IS THE THIRD LOW TIME ENGINE WE HAVE FOUND WITH WORN EXHAUST GUIDES IN THE LAST YEAR. THE CYLINDER WAS REMOVED FROM SERVICE.