Chrysler multi-bank tank engine. Click image to enlarge
Article and photo by Bill Vance
The North American automobile industry made such a significant contribution to the Allied cause in the Second World War that it rightly became known as the “Arsenal of Democracy.” Every manufacturer, large and small, played an important part in supplying the myriad types of equipment required to fight a highly mechanized war.
Products included Rolls-Royce Merlin aircraft engines from Packard, B-24 Liberator Bombers from Ford, trucks from General Motors, Reo, Studebaker, International-Harvester and others, Jeeps from Willys and Ford. There were army tanks from several manufacturers.
It was a massive war effort, and recognizing the vital role that the automobile industry would be playing, U.S. President Franklin Roosevelt placed the president of General Motors, William S. Knudsen, in charge of the Office of Production Management, responsible for overseeing and coordinating the production of war material.
One of the vital war machines was the military tank, and since these were foreign to anything the industry had built previously, the approach could best be described as pragmatic. Aircraft engines were initially used to power tanks but when it became apparent that these were urgently needed for airplanes, other power sources had to be found.
General Motors fitted its tanks with Cadillac V8 engines and Hydra-Matic transmissions. Ford, strongly associated with the V8, developed an 18-litre (1,100 cu in.) double overhead cam, four-valve-per-cylinder (remember that this was in the early 1940s!) V8 for use in tanks. It developed 500 horsepower at 2,600 rpm. They also experimented with a 27-litre (1,650 cu in.), fuel injected V12 tank engine producing up to 800 horsepower.
But the most unusual approach was that taken by the Chrysler Corporation to power M4A4 Sherman tanks. Although it didn’t involve the use of any exotic new engine technology, it did demonstrate a very imaginative application of existing hardware.
It was called the Chrysler Multi-bank tank engine, and it was constructed by mounting five Chrysler car engines on one big common crankcase. Each six-cylinder, side-valve engine had a bore and stroke of 87.3 mm by 114.3 mm (3.43 X 4.5 in.), yielding a displacement of 4.1 litres (250.6 cu in.). The total displacement of the multi-bank was 20.5 litres (1,253 cu in.), and approximate weight was 2,404 kg (1,100 lb) with clutch and radiator.