Construction used separate cast iron blocks for each pair of cylinders, mounted on a light-alloy crankcase with an included vee angle of 50 degrees. Each bank had a single
overhead camshaft, shaft-driven through bevel gears. It was equipped with a single dual-choke updraught
Zenith carburettor, and twin spark
ignition through four
magnetos. The
crankshaft was a flat plane with three bearings and four throws, each pair of cylinders sharing a master-slave
connecting rod onto the same crankpin. ==Variants==