What was found
CYLINDER NR 3 EXHAUST VALVE PUSH ROD BROKE, DUE TO A STUCK VALVE IN THE CLOSED POSITION. THE VALVE WAS NOT STUCK AT THE TIME OF THE INVESTIGATION. NO MARKS WERE SEEN ON THE TOP OF THE PISTON AS VIEWED THROUGH A BORESCOPE. THE SPARK PLUGS HAD ONLY SLIGHT BLACK SOOTY APPEARANCE WITH LEAD FOWLING DEEP IN THE INSULATOR. OTHER SPARK PLUGS HAD A TAN APPEARANCE. THE LIFTER CAME APART AS A RESULT OF THE BROKEN PUSH ROD BUT APPEARS TO HAVE BEEN OPERATING PROPERLY PRIOR TO THE EVENT.