The cylinder head is he 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 of the Aramide
fibre type, and there is no need to retighten the cylinder head
at all during the life of the engine.
BI-FUEL/METHANE
The cylinder head specifications are the
same as for a petrol fuel system with exhaust valve seats made from
a special material to prevent the oxidation by the combustion products
of the methane.