MB862

Set the MB 862 alongside the water-cooled MB 852 and they are the same engine in different clothes: 115 × 140 mm cylinders, 2.9 liters, 40 PS at 2,000 rpm, 18.5:1 compression, overhead valves. Even the scales barely separate them, the air-cooled unit coming in at 411 kg dry against a little over 400 for the version with a jacket and a radiator — finning and a blower cost roughly what a cooling system costs. Peak torque of 152 N·m arrived at 1,500 rpm, which tells you plainly what the engine was drawn to do.

Daimler-Benz ran the two families in parallel rather than choosing between them, and the workshop literature admits it: a single parts book covered the MB 854 with the MB 864, and the MB 856 with the MB 866 — water-cooled and air-cooled fours and sixes bound into one volume because so much of the hardware was common. For a machinery builder the decision was about the site rather than the engine. Where dust, frost or an absent maintenance man made a water circuit a liability, the 860 went in; where it did not, the 850 did.