As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKE OFF AND IN CLIMB OUT, THE TOWER REPORTED SMOKE TRAILING THE LEFT ENGINE. RETURNED TO DEPARTURE WITHOUT INCIDENT. REMOVED COWL AND FOUND OIL DRIPPING FROM THE NR 3 CYLINDER. FOUND THE GASKET ON THE NR 3 CYLINDER HAD COLLAPSED IN UPPER RIGHT CORNER. REPLACED THE VALVE COVER GASKET AND CLEANED OIL RESIDUE. RAN ENGINE FOR LEAK AND OPERATIONAL CHECKS, NO LEAKS AND PERFORMANCE NORMAL.