As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPON ENGINE DISMANTLE OR OVERHAUL, 5 OUT OF 6 CYLINDERS HAD CRACKED CYLINDER HEADS. THE CRACKS ORIGINATED AT THE LOWER SPARK PLUG HOLE AND RADIATED OUT AT THE 4 O`CLOCK POSITION FOR APPROX 1 INCH. AFFECTED SN: NR 1- 526-A08-6899. NOTE: THIS INFO WAS SUBMITTED BY AN UNKNOWN PERSON TO THE FSDO. NO OTHER INFO AVAILABLE.