 However, most advanced engine research is concentrated on improving other internal combustion engine designs, such as the Wankel.Mike Hewland with his assistant John Logan, and also independently Keith Duckworth, experimented with a single-cylinder sleeve-valve test engine when looking at Cosworth DFV replacements.Hewland claimed to have obtained from a 500 cc single-cylinder engine, with a specific fuel consumption of 177-205 g/HP/hr (0.39 - 0.45 lb/HP/hr), the engine being able to work on creosote, and with no specific lubrication supply for the sleeve.