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The study described in this paper covers the development of the Sequence IVB low-temperature valvetrain wear test as a replacement test platform for the existing ASTM D6891 Sequence IVA for the new engine oil category, ILSAC GF-6. The Sequence IVB Test uses a Toyota engine with dual overhead camshafts, direct-acting mechanical lifter valvetrain system. The original intent for the new test was to be a direct replacement for the Sequence IVA. Due to inherent differences in valvetrain system design between the Sequence IVA and IVB engines, it was necessary to alter existing test conditions to ensure adequate wear was produced on the valvetrain components to allow discrimination among the different lubricant formulations. A variety of test conditions and wear parameters were evaluated in the test development. Radioactive tracer technique (RATT) was used to determine the wear response of the test platform to various test conditions.

With the impending development of GF-6, the newest generation of engine oil, a new standardized oil oxidation and piston deposit test was developed using Chrysler 3.6 L Pentastar engine. The performance requirements and approval for passenger car light duty gasoline engine oil categories are set by the International Lubricants Standardization and Approval committee (ILSAC) and the American Petroleum Institute (API) using standardized testing protocols developed under the guidance of ASTM, the American Society for Testing and Materials. This paper describes the development of a new ASTM Chrysler oxidation and deposit test that will be used to evaluate lubricants performance for oil thickening and viscosity increase, and piston deposits.