I ve got contract for repairing Tiger II. but i ve got the situation where one engine head is missing, although all things above it, valves, sparkplugs, camshafts and all others are present, but repairing stops when timing cover should be insert. so i reversed the repair until all pistons are removed and reinserted, and the game calls for engine head. but this can not be installed. it switched to bolt camera but now bolt appears to be screwd in. so i am stuck.