As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE PILOT REPORTED A ROUGH ENGINE AND MADE A PRECAUTIONARY LANDING. A COMPRESSION GAUGE REVEALED THE NR 2 CYLINDER LEAKING BETWEEN THE HEAD AND BARREL (6 INCHES FROM THE MOUNTING FLANGE). THIS IS BETWEEN THE COOLING FINS AT THE BASE OF THE EXHAUST PORT. THE CRACK IS ABOUT 4 INCHES LONG. THE CYLINDER WAS WAS REMOVED AND A NEW ONE INSTALLED.