The cylinder head is the monolithic type
made from aluminium alloy.The four valves per cylinder are mounted
in their respective guides, operated by two camshafts via hydraulic
tappets. The valve guides are installed by interference
fit in their seats in the cylinder head.The inner diameter is finished off after
assembly, using a specific reamer.The camshafts are fitted in two integral
camshaft housings, without a tappet cover.The cylinder head gasket is the two layer
metal type 0.5 mm thick and there is no need to retighten the cylinder
head at all during the life of the engine.