The crankcase is in ductile cast ironThe cylinders are formed directly in the
engine block, and are graded into three sizes plus one oversize.The crankshaft is supported by five main
bearings (1).There are special channels in the engine
block walls which allow the flow of coolant and lubricating oil.At the bottom of each cylinder, there is
a jet (2) from which oil is sprayed onto the piston crown to cool
it and ensure the lubrication of the gudgeon pin.
LOWER CRANKCASE
The lower crankcase is made out of pressure
cast aluminium alloy, with cast iron main bearing caps.The mounts and main bearing caps are machined
together with the upper crankcase.The lower crankcase is fitted to the upper
crankcase by means of bolts and locating dowels to ensure greater
precision.A strip of sealant is applied between both
crankcases to prevent engine oil leaks.The figure below shows the upper crankcase
(1) and the lower crankcase (2).
