As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 4 CYLINDER FOUND CRACK AT BARREL BETWEEN COOLING FINS. CRACK WAS APPROX 300 DEGREES AROUND CYLINDER CIRCUMFERENCE. SYMPTOMS INCLUDED ROUGH RUNNING, LARGE OIL LEAK AND SMOKE. CATASTROPHIC FAILURE WAS EMANATE AND WOULD HAVE CAUSED COMPLETE LOSS OF ENGINE POWER. (K)