As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER HEAD CRACKS HAD BEEN FOUND ON ANOTHER CYLINDER INSTALLED ON THIS ACFT ENGINE, MECHANICS DECIDED TO BORESCOPE THE REMAINING 3 ENGINE CYLINDERS AND DISCOVERED CYLINDER NR 2 ALSO HAD CRACKING TO EITHER SIDE OF ITS LOWER SPARK PLUG HOLE. THE CYLINDER WAS NOT DISCOLORED AS THOUGH IT HAD SEEN EXTREME HEAT, NOR DID IT HAVE ANY BROKEN OR BENT FINS OR ANY OTHER DAMAGE THAT WOULD CONTRIBUTE TO A CRACKING.