The presence of MOS2 in the engine oil did not appear to adversely affect the emission levels of hydrocarbons, CO, or NOx. Clemson University, Dept. of Mechanical Engineering, Clemson, SC in a review of existing technical and test data - Moly has been well proven to be a viable and effective additive to any lubricant in numerous applications and types of equipment. The addition of moly has been shown to improve fuel economy and more importantly, to increase the useful life of a mechanical device through the reduction of wear. Mich. Test Report - Friction modified oils significantly reduce valve train friction. By contrast, oil viscosity had only a minor influence.
Friction reducing oil additives reduce valve friction substantially.