The Bugatti Type 30 engine is a straight eight, single overhead cam (SOHC) design. It features three valves per cylinder --- two intake valves, one exhaust valve. The camshaft is a front/bevel type.
Bugatti used these engines in the 1922-1926 Type 30 automobiles and in the Type 29 racer.
The eight cylinder engine was constructed to meet the 1922 Grand Prix regulations limiting engine displacement to just two liters. The 'Type 29/30' was built up of two blocks of four cylinders and featured three valves per cylinder (two intake and one exhaust). Mounted vertically in the head, the valves are actuated by one overhead camshaft.
The crankshaft is supported by just three main bearings. This would become one of the weak spots of the design, particularly in racing. Depending on the state of tune, the engine produced between 75 and 100 bhp.