Laboratory development of modern diesel engine lubricants should ideally be done at the high output/speed conditions where the latest engines operate. In the late 1960's, the only engines available to the oil industry were the Caterpillar 1Y73 and the Petter AV-1. While useful test tools, neither of these engines can successfully operate at the desired conditions. Nor can they be successfully modified for that purpose.For these reasons, a joint project was established in 1969 between Chevron Research and List-Rosen-Wittek/AVL. Its purpose was to adapt one of the AVL diesel development engines to lubricant, emission, and fuel research. The design criteria developed included modern speed/output capability, durability, low maintenance, special lubrication features, adaptability, and balancing. These requirements resulted in a completely new design. A prototype was constructed, and this engine ran in October 1972. The design features are described and illustrated. The engine is now being installed in the Richmond Laboratory of Chevron Research Company.