The cylinder head is of the monolithic type,
of aluminium-silicon alloy.Two cast iron camshafts, in a camshaft housing;
driven by a belt and gears.The four valves per cylinder, parallel and
vertical, are positioned in the valve guides and operated by rockers
controlled by camshaft cams kept in contact with the valves by means
of hydraulic tappets.The valve guides are installed by interference
fit in their seats in the cylinder head. The bore is finished off
after assembly, using a specific reamer.Compared with heads with precombustion chambers,
the entire combustion process takes place in the combustion chamber in
the piston.The cylinder head gasket is of the multilayer
metal type, and there is no need to retighten the cylinder head
at all during the life of the engine.