Actuality. Meaning of efficiency coefficient of internal combustion engine fully depends on type and construction. Common world practice of automobile construction is directed on increasing of quality of indicators of usage of internal combustion engine, which is linked to directions of increasing efficiency. Leading overseas firms that “dictate” the engineering direction of the design improvement of internal combustion engines in connection with the improvement of the technology of processing fuel into mechanical work in the engine use various technological opportunities in conjunction with the design developments in the cylindrical piston group. That’s why modernization elements research of cylinder piston group is relevant. Goal. Research possible ways to increase efficiency internal combustion engine by modernization of cylinder piston group due to the scientific work plan. Task. Design measures for internal combustion engine modernization for increasing of quality of its usage. Research methodology. Due to methodology [2] we performed theoretical calculations of efficiency of real engine and efficiency of engine which cylinder piston group was upgraded. While we defied indicating efficiency of patrol engine ZMZ-406 we used auxiliary equation of B. Stechkin. We performed theoretical calculations of functional dependence of efficiency because of working body parameters changes simultaneously.