Gray Marine diesel engines of WW II

grabcad

Human: The Gray Marine series of six-cylinder 426 cu in engines of WW II introduced by Detroit Diesel, a division of GM, debuted the 71 series of diesel engines in 1938 with 71 cu in per cylinder. Initially, four original models were developed, comprising 2, 3, 4 and 6 cylinder engines designed for diverse applications. Two-stroke diesel inline configuration was utilized, with an overhead cam driving exhaust valves and injectors alongside a perforated cylinder sleeve for intake purposes. A gear train powered the camshaft, balancer shaft, blower, and connected pumps behind the engine block. Production of the 71 series persisted until 1998. Detroit Diesel received a critical task in late 1941 as the US prepared for war: adapting the six-71 engine for naval use necessitated accommodating sea water cooling. To meet this demand, Gray Marine developed a separate pump and heat exchanger to maintain internal fresh water cooling within the engine alongside sea water cooling of the exhaust manifold. Early models, like the 64HN5, integrated a Borg-Warner transmission that also harnessed sea water for cooling. This feature was abandoned in all subsequent transmissions designed by Twin Disc. In the 71 series' production phase, key components including blocks, cylinder heads, crankshafts, camshafts, valves, injectors, and mechanisms were identically produced as in the 6-71 engines. Approximately 100,000 of these WW II-era diesel engines were manufactured during wartime by Gray Marine. The engine models varied significantly in applications ranging from 36 foot landing crafts like LCP(L)'s, to others such as LCVP's.