80 hp signified a quantum leap in 1974: The five-cylinder diesel engine on board the Mercedes-Benz 240 D 3.0 produced such an output, making the model series 115, commonly known as the “Stroke/8”, the torquiest and fastest diesel-powered passenger car in the world. The diesel engine combined strong driving power with impressive economy. At the same time, the 240 D 3.0 was the first series-production car with a five-cylinder engine.
The engineers developed the five-cylinder in-line engine OM 617 for use in series-production cars on the basis of a 2.4-litre OM 616 engine. The latter’s proven characteristics were retained, but the five-cylinder engine was provided with a new Bosch injection pump which was connected via oil ducts to the engine’s oil circuit and was thus maintenance-free. A mechanical governor replaced the pneumatic governor which was customary for the smaller diesel engines. This benefited driving comfort – the 240 D 3.0 with manual transmission revealed virtually no load alteration effects, and with automatic transmission gear-changing was substantially smoother in the partial load range.