Early engines used a crankshaft, connecting rods and pistons from Lotus. The crank was cast iron, and the pistons had a slight crown and were fly-cut to clear the valves. A revised Twin Cam was released in 1966. In this version the fly-cuts were smaller, and the con-rods were Ford 125E parts. The flywheel was also attached to the crankshaft by six bolts, an increase of two over the previous model. The Twin Cam had a problem with oil surge, and the attachment of the starter motor was subject to flexing when trying to spin the high-compression engine.