What was found
AFTER TAKEOFF, PILOT NOTICED ROUGHNESS IN RIGHT ENGINE, HE REDUCED POWER, ENGINE RAN SMOOTH FOR A SHORT TIME THEN BECAME ROUGH AGAIN. AT THIS TIME, OIL WAS NOTED ON THE TOP OF RIGHT COWL. THE PILOT FEATHERED THE ENGINE AND LANDED. NR 2 CYLINDER WAS FOUND SEPARATED FROM THE CASE AND TOP THROUGH-BOLT FOUND BROKEN. CANNOT DETERMINE WHICH FAILED FIRST, THE BOLT OR THE CASE.