Detroit Diesel Series 71
The Detroit Diesel Series 71 was introduced as the initial flagship product of the Detroit Diesel Engine Division of General Motors in the division's 1938 founding. It is a two-stroke cycle diesel engine series, available in both inline (the company's initial available engine configuration) and V (introduced in 1957) configurations. The inline types ranged from one to six cylinders and the V types ranging from six to 24 cylinders. Power ratings ranging from 15 to 1100 hp.
The 71 series engines utilized uniflow scavenging, where a Roots blower mounted to the exterior of the engine providing air at greater than cylinder pressure (positive displacement), and exhausted through two or four exhaust valves per cylinder. The supercharger was used to provide positive displacement, required for a two stroke cycle, instead of using the crankcase as commonly used on small high speed gasoline motors. Later high performance versions were available with turbochargers, and turbochargers with aftercooling. This was signified with a "T" or "TA" model name suffix respectively. An "N" suffix was used for a naturally aspirated engine.
The most popular incarnations of the Series 71 diesel as used for highway vehicle applications included the inline 6-71 and the V-block 6V71. An eight cylinder V-block (8V71) was introduced for sale in 1957.
The inline 6-71 engine, in all of its versions, was also available as a horizontal or 'pancake engine'. This was called the 6L-71 or 6N-71. It saw use in Crown Coach Corporation and Gillig school buses and articulated puller transit buses such as the Orion Bus Industries Orion III/Ikarus 286.
Models Used In Buses
- 6-71 - I6, 7.0 litre
- 6V71N - V6, 7.0 litre
- 8V71N - V8, 9.3 litre
- 8V71T - V8, 9.3 litre, turbocharged
- 8V71TA - V8, 9.3 litre, turbocharged and aftercooled
- 8V71TAE - V8, 9.3 litre, turbocharged and aftercooled (environmental)
- 12V-71N - V12, 14 litre