Camshaft-Tappet Problems in Ford Overhead-Valve Engines

IN THE first part of this paper dealing with the metallurgical aspects of the camshaft-tappet problems met with in the design of the new Ford overhead-valve V8 engines, Messrs. Laird and Stevens describe the events which led to the adoption of the as-cast alloy-iron camshaft, nitro-carburized martensitic tappet combination. The combination cited works well in the engines described, but it is not implied that it will perform satisfactorily elsewhere.

In the second portion of the paper, Mr. Iles discusses the test schedule devised in connection with the development of the camshaft-tappet materials in the new engines. It is stated that important findings will occur when such tests involve a large number of parts, making possible the study of results on a frequency basis. Tests have shown that a predominantly martensitic tappet structure results in superior performance in combination with the as-cast alloy-iron camshaft used.