Catcams mechanical race cam followers are designed to provide a reliable lightweight conversion from OEM cam followers. After dedicated heat treatment of the high grade steel, all cam followers are ground to precision and the top surface gets a superb finish by diamond lapping. As a default, all cam followers are coated to reduce friction against the cam lobe.
hydraulic cam follower conversion
Direct tappet (or bucket) type cam followers with hydraulic lash adjustment have mainly 2 disadvantages: weight and reliability at increased rpm range.
An even more important reason to replace hydraulic cam followers by Catcams solid race cam followers is the reliability of the hydraulic valve element that provides the automatic valve lash adjustment. At increased rpm, the inner valve is no longer able to cope with the inertia forces. In combination with the disturbed oil feed at high rpm, the oil is not correctly released and the hydraulic adjuster starts to expand. In the best case scenario, this phenomenon creates a 'natural' rpm limit for the engine due to compression loss. However, when there is only a limited clearance between valves and piston, the pumping effect will generate sufficient extra valve lift to cause valve to piston contact.
solid 'shim over' cam follower conversion
Many engines that use solid direct tappet cam followers have shims that are located on top of the cam follower. This allows to adjust the valve clearance without removing the camshaft. Although this solution is very appealing for servicing, the available contact surface for the cam follower is limited. Replacement by Cat Cams race cam followers provides extra area for high lift / short duration cam lobes. As a bonus, the weight is reduced significantly.