As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE S/N L-19263-51E WAS FOUND WITH A STICKING EXHAUST EXHAUST VALVE AT 385.3 HOURS TOTAL TIME. LYCOMING SB388C WAS PERFORMED, ALL THE GUIDES WERE REAMED WITHIN BALANCE. THIS ENGINE INCORPORATES NI-RESIST VALVE GUIDES AND THE TIME TO FAILURE IS CONSIDERED BY THIS AGENCY TO BE PREMATURE.