The single sleeve valve four-cycle automobile engine, designed on a new principle, developed in the automotive research laboratory of Massachusetts Institute of Technology in cooperation with its inventor, Luther A. Gaw, of Cincinnati, who is shown running the engine on a water brake test. the outstanding feature of the new engine which is pronounced a notable advance in sleeve valve motors, is the single light steel sleeve valve of steel, which slides between the cylinders wall and the piston, The engine is almost noiseless in operation and has shown fuel and oil economy in road tests of more than 10,000 miles.