Some Factors Governing the Performance of Crankcase Lubricating Oils

Abstract

The paper deals in turn with the basic requirements of a crankcase oil; chemical and physical tests on new and used oils; viscosity, S.A.E. numbers, and viscosity index; common problems arising in lubrication; ring sticking; engine wear; oil consumption; bearing failures; engine deposits; the grouping of oils; the influence of Diesel fuel and gasolene on engine deposits and wear; engine laboratory tests; the rating of oil performance on an engine test; and finally, the correlation between field and laboratory tests. It attempts to show that unsatisfactory engine life is not necessarily connected with the quality of the lubricating oil, and that many of the faults often attributed to the lubricant are, in fact, controlled by incorrect engine design, excessive operating conditions, or poor maintenance. Better results can usually be obtained by the use of additive treated oils. Reference is made to the Supplement 1 series of oils which effectively deal with high-sulphur Diesel fuels, and examples are given of bench and field tests carried out on straight and treated oils.