Design

Camshafts, Valve system
The camshafts are cast iron. The cams lobes which press against the valve lifters are harder to tolerate the contact pressure. The valve lifters are steel and mechanical, not hydraulic.

There is a certain amount of valve clearance between the valve lifters and cam lobes. The valve clearance is adapted to compensate for differences in length between the valve and cylinder head due to expansion when warming up. Mechanical valve lifters ensure more precise valve timing, reduced friction, more stable combustion and reduced mass.

The material in the lifters is casehardened steel. The surfaces between the camshaft and valve are slightly convex to guarantee centered contact.