The main body of the roller type rocker arm is preferably made from aluminium or steel; it is fitted with:

• a pin
• a needle bearing cam roller
• a hydraulic insert element

Advantages:

• Very low valve train friction
• Very little space is required, since all the valves can be activated by a single camshaft

Special designs of rocker arm allow activation of 1, 2 or 3 valves. Each valve contact has one insert element which hydraulically adjusts the valve lash of each valve.

Hydraulic insert element with contact pad

• The contact pad made from hardened steel
• Supported with a swivel facility on the insert element by means of a ball/socket joint
• Very low contact pressures in the cam contact area
• Advantages of hydraulic valve lash adjustment correspond to those of the tappet