Engine Block: Pistons

The pistons are made of light alloy and have grooves for two compression rings and one oil scraper ring.

The upper compression ring is flat and chrome or molybdenum plated. The lower compression ring acts as an oil scraper, is somewhat wider than the upper compression ring and has three sections. The pistons are internally reinforced and designed for trapezoid connecting rods. The pistons are tin plated and their upper parts hard anodized. The gudgeon pins are nitro-hardened. The compression ratio of the B205 is 8.8:1 and of the B235 9.3:1.