As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A COMPRESSION CHECK ON CYL NR 5 RESULTED IN A RATIO OF 20/80. INSP REVEALED A CRACK IN THE CYL HEAD ALMOST THE ENTIRE WIDTH OF THE HEAD, THAT RAN BELOW THE SPARK PLUG HOLE AND ABOVE THE FUEL INJECTOR PORT. INSP OF THE INTERIOR OF THE CYL SHOWED THE CRACK RUNNING BETWEEN THE INTAKE AND EXHAUST VALVE HOLES. INSPECTION OF THE OTHER CYLINDERS REVEALED A SMALL CRACK RADIATING FROM THE SPARK PLUG HOLE ON CYL NR 3. BOTH CYLINDERS WERE INSTALLED NEW AT ENGINE O/H AND HAD 824 HRS. (K)