Cylinder Head Assembly: Description and Operation

Cylinder Head/Valve Train:

The cylinder head of the M44 engine has been redesigned to incorporate design features from the M73 engine.

The bucket type HVA tappets and tappet rail have been deleted. The M44 cylinder head uses roller rockers and free-standing HVA elements to actuate the valves. The use of roller rockers reduces the overall rotating friction in the valve train.

The intake and exhaust valves are carried over from the M42 engine, however the exhaust valves are no longer sodium filled. The M44 uses a single, conical design valve springs for weight savings.

The camshafts are hollow cast iron with the concave contour lobes for the roller rockers arm actuation. The lift of the cams is 9.7 mm, however the intake and exhaust cams are different. The opening duration spread is different for each. The intake cam has a opening duration/spread of 240°/104° and the exhaust is 244°/114°.