Virabrequim
Mini: 1275 cc Cooper S
EN40B steel - for 1300cc engine block, stroke 81.3 mm, connecting rod journals 1.625" (Cooper S), main bearing 1.211"
Forged EN40B crankshaft, with 1.75" connecting rod journals for 1300 CooperS block, with thicker keyway for timing gears. Forged EN40B steel nitride racing crankshafts are considered the ultimate in specification, even ahead of the ¡®billet¡¯ types. This is mainly due to the fact that the grain structure of a forged part follows the shape of the webs and bearings, whereas the billet type is machined across the grain structure. The crankshafts have excellent oil distribution channels and are heat-treated for maximum durability. All are machined to fit 1275 Cooper-S size 1.211" main bearings.
These crankshafts have been redesigned to take advantage of the latest technology. The larger crankshaft webs have been designed to produce less vibration and drag at high rpm, resulting in smoother running and easier balancing. They are also mass-centred and balanced.
Always check the air clearance to the gearbox with these large connecting rods. The holes for the connecting rod ends reduce the weight of the crankshaft and do not require the large C-shaped balancing webs to be drilled through.