As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ENGINE FOUND TO BE CRACKED. THE FRACTURE OCCURRED ON THE LEFT HAND CASE HALF RUNNING FROM THE 9 OCLOCK POSSITION OF THE NR 2 CYLINDER PAD TO THE MAIN BEARING BOSS AREA. THIS CRACK WAS CAUSED BY POOR SCAVENGING OF AIR DURING THE CASTING PROCESS.