As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB OUT, PILOT HEARD A BANG/POP SOUND FORWARD OF COCKPIT. LOST SOME POWER AND RPM. NOTICED DROP IN NR 1 CYLINDER TEMP ON ENGINE INDICATING SYS. RETURN TO FIELD, NORMAL LANDING. ACFT SHUTDOWN. POST FLIGHT INSPECTION REVEALED A HEAD TO BARREL SEPARATION OF THE NR 1 CYLINDER.