M189

The 300 d of 1957 brought the first intermittent manifold injection fitted to a Mercedes-Benz passenger car. The 300 Sc and the gullwing sprayed petrol straight into the cylinder, which diluted the oil and demanded a pump made to extreme pressures; spraying into the inlet tract was simpler, and with raised compression it was worth 160 PS against the carbureted 300 c’s 125. A three-speed automatic was standard, air conditioning appeared on a Mercedes-Benz passenger car for the first time, and the heaviest of the state limousines finally moved like a fast one.

In 1961 the engine was recast for the W 112 300 SE with both block and head in light alloy — the first production Mercedes-Benz engine built that way — shedding some 40 kg against the gray-iron versions in the 300 SL and the Adenauer, lightening the front axle and dialling out understeer. From January 1964 a six-plunger Bosch injection pump replaced the two-plunger unit and output rose to 170 PS. In that form it carried the W 108 and W 109 saloons until 1967, when the M 130 took over.