As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING DIFFERENTIAL COMPRESSION TEST, AIR WAS HEARD LEAKING FROM LOWER CYLINDER AREA. COMPRESSION WAS 40/80. USING LIQUID LEAK DETECTOR, FOUND AIR BLOWING OUT FROM A CRACK IN CYLINDER FIN. REMOVED CYLINDER FROM ENGINE AND NOTED A CRACK IN THE COMBUSTION CHAMBER RUNNING FROM LOWER SPARK PLUG HOLE TO INTAKE VALVE.