Fairbanks Morse 38 8-1/8 diesel engine

The Fairbanks Morse 38 8-1/8 is a two stroke, opposed piston diesel engine developed in the 1930s as a licensed American adaptation of Germany's Junkers Jumo 205 aircraft diesel, with combustion occurring between two pistons within a single cylinder liner rather than against a fixed cylinder head. It became the standard propulsion for United States diesel-electric submarines of the Second World War and the 1950s and still serves as backup power on most U.S. nuclear submarines, remaining in continuous production since 1938 as the modified 38ND 8-1/8 aboard Los Angeles, Seawolf and Ohio class boats.