As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE FOUND TO MAKE WHISTLING SOUND WHEN PROP PULLED THROUGH ON PRE-FLIGHT. INSPECTION FOUND THE NR 1 CYLINDER HEAD CRACKED AFT OF THE INTAKE VALVE. CRACK LENGTH APPROXIMATELY 2 INCHES IN LENGTH. THIS CYLINDER PRESSURE CHECKED GOOD 5.98 HOURS EARLIER WHEN IT WAS FOUND THAT THE NR 3 CYLINDER HAD THE SAME CRACK AND NEEDED TO BE REPLACED.