As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
INTAKE VALVE AND SEAT, CYLINDER NR 1 NOT SEALING. APPEARS THAT VALVE SEAT AND / OR VALVE WERE IMPROPERLY GROUND. THIS PATTERN IS NOT CONSISTANT AROUND CIRCUMFERENCE OF VALVE. ONE SECTION OF SEAT (APPROX .7500 INCH)APPEARS TO HAVE ON CONTACT WITH VALVE.