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Special test methods under low temperature, low speed, and moderate temperature, moderate speed operating conditions were devised to evaluate the anti-wear properties of engine oils upon the engine valve train. Many commercial and some test oils were utilized to determine the factors affecting valve train wear. Test results indicate that the low temperature and low speed test conditions were the more severe for the valve train. No simple correlation was found between the concentration of Zn-DTP and valve train wear, however, the influence of dispersant-detergent additives was found to be significant. The chemistry of such additives showed different tappet scuffing characteristics.