This paper presents a background of the cam and tappet wear problem encountered by the automotive industry during the evolution of the modern overhead valve V-8 engine. Investigation of the numerous factors affecting this problem revealed that engine oil composition was of major importance. The development of a test technique to determine the adequacy of engine lubricant antiscuff properties is described and evidence of correlation with field experience is presented.
This test technique was accepted by Section G-IV of Technical Committee B on Automotive Lubricants of ASTM Committee D-2 on Petroleum Products and Lubricants in October, 1959, as test sequence IV. This test was one of a series of test sequences to be used for evaluating oils for API Service MS. Starting with ASTM STP No. 315, the engine test sequences for evaluating oils for API service MS are prepared and released for publication by Section I on Engine Oils of Technical Committee B of ASTM Committee D-2.
Modifications made in the test procedure since its original publication are described along with a summary of experience obtained to date with this test technique.