The crankcase is made from ductile cast iron.The cylinders are formed directly in the crankcase and sorted into three size categories plus one oversize.The crankshaft is supported by five main bearings (1).Special channels in the crankcase walls carry coolant and lubrication fluid.The lower part of each cylinder contains a jet (2) that sprays oil onto the piston crown to cool it and to ensure the piston pin is lubricated.
LOWER CRANKCASE
The lower crankcase is made from die-cast aluminium alloy with cast iron main bearing caps.The machining of the supports and main bearing caps is carried out together with the crankcase.The matching with the upper crankcase is achieved by means of bolts and locating dowels which guarantee the precision of the fitting.There is a bead of sealant between the two crankcases to prevent engine oil leaks.The upper crankcase (1) and the lower crankcase (2) are illustrated in the diagram below.
