Orenstein & Koppel / Mba SA
1 model in this series
Orenstein & Koppel/Mba SA751 (1938-1943): two-cylinder diesel tractor with water cooling, 22.1 kW output and a top speed of 16 km/h from the SA series
Orenstein & Koppel built farm tractors alongside light railways and construction machinery, and on this model appeared jointly with the Mba designation. The SA751 from the SA series was built between 1938 and 1943, mostly during the Second World War, a period when raw materials for civilian farm equipment were scarce.
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The water-cooled two-cylinder diesel engine displaces 3,532 cm³ and delivers 22.1 kW at 1,300 rpm, equivalent to 30 horsepower. With a weight of 2,245 kg, a wheelbase of 1,930 mm and a width of 1,620 mm, the tractor was noticeably larger and heavier than the smaller SB model from the same maker. The top speed of 16 km/h shows a drivetrain built for drawbar work rather than road travel.
Two-cylinder diesel engines of this size were a common solution for mid-weight farm tractors in the 1930s and 1940s, offering more pulling power than smaller single-cylinder designs without the higher purchase and running costs of engines with four or more cylinders. Water cooling with a radiator, unlike thermosiphon cooling, required a circulation pump but delivered more even cooling under load.
For a used vehicle of this age and origin, the cooling system including pump and radiator should be checked for leaks, since spare parts for wartime model years are rarely available in original condition. The injection pump and fuel lines also deserve attention, as low-quality fuel from the period often permanently damaged the injection system.
Sources: SpecCodex-Register: Kennwerte des Modells SA751
Models
Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.