As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED LOUD BANG ON CLIMBOUT. RETURNED WITHOUT INCIDENT TO FIELD. UPON EXAMINATION FOUND NR 4 CYLINDER HEAD SEPARATED FROM CYLINDER AT 5TH COOLING FIN ON HEAD. ENGINE TSO AND CYLINDER TSN 817.6 HRS. LAST COMPRESSION CHECK WAS AT 100 HR INSPECTION 19.2 HRS PRIOR WITH COMPRESSION 69/80.