Munktells BM 4

To ensure that the manufacture of tractors did not come to a complete standstill during the war, Volvo purchased one hundred FCG carburettor engines for producer gas operation, to be installed in BM 2 chassis. The engine delivered 30 hk at 1 500 r/min in the tractor. This meant that the gear ratios had to be changed. The gearbox was available with a ratio of iron wheels and two different ratios for rubber wheel, with top speeds of 14 and 15 km/h respectively.
Engine and gearbox were mounted on BM 2 chassis. The producer gas unit required an electric fan, so the machine was equipped with a battery, a generator and a starter motor. The overall length of the tractor was 1 900 mm, compared with 1 780 mm for the BM 2. The only other major change that had to be made was to move the pulley to the right-hand side of the machine, since the producer gas equipment was better suited fo r mounting on the left.
BM 4 specifications
Engine Volvo FCG
Cylinders 6
Cylinder capacity, l 4,4
Rated output, hk 32
Gears, forward/reverse 4/1
Wheelbase, mm 1 900
Weight, kg 2 350
Production no. 100
Production year 1939–1945