Bührer B
1 model in this series
Bührer BG4: four-cylinder tractor of the B range with a wood-gas option, 50 hp, 1,600 kg unladen weight, built 1937 to 1942
Bührer, a Swiss tractor maker based in Hinwil in the canton of Zurich, was among the early makers of field tractors developed and built in Switzerland. The BG4 in the B range was built from 1937 to 1942, in the years immediately before and during the Second World War.
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The BG4 carries a water-cooled four-cylinder engine of 3,285 cm³ displacement with rear-wheel drive, running on petrol, low-grade petrol or wood gas, producing 50 hp; a 4V-1R gearbox provides four forward and one reverse gear. With an unladen weight of 1,600 kg, the BG4 was built for the mid-sized Swiss farms of its day, for tillage and everyday draft work around the farmyard.
The wood-gas option reflects the fuel shortages of the war years, when Switzerland was largely cut off from oil imports by the Allied and German economic blockade: an onboard generator produced combustible gas from wood or charcoal to run the petrol engine instead of petrol itself. This conversion was common in Swiss farm machinery and vehicles during the war.
When buying such an old model second-hand, the condition of the engine and carburettor, the tightness of the cooling system, and rust on the sheet-metal parts and chassis matter. If a wood-gas generator survives with the vehicle, its condition further decides the vehicle's museum value, since matching components are no longer made and originality is what collectors look for.
Sources: SpecCodex-Register: Kennwerte des Modells Bührer BG4
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