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Area of application

Agricultural tractor for two-furrow plough. Because the tractors were starting to be fitted with rubber tires, road transportation with tractors became increasingly normal.


At the start of the second World War, a fuel stop was introduced to the private market and for those who wanted to continue driving their tractors, wood gas unit became a solution.

A few hundred BM 2:s were made during the war years under the name Munktells GBM 2.

To be able to drive on wood gas, you had to rebuild the engines with new cylinder caps with sparkplugs and magneto. The pulley was moved to the right side to give space for the wood gas container.

The gearbox’s gearing changed depending on if the tractor had iron- or rubber tires.

Hesselmans wood gas unit was also available for the tractors made previously that were still in use on farms.

When the war eventually ended you could rebuild the industrially made wood gas driven tractors with a conversion kit for compatibility with the conventional fuel.

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Munktells GBM 2

Introduced                                                          1942

Engine                                                                 Bolinders W5, 2-cyl, 2-stroke                                                                                        hot bulb engine rebuilt for                                                                                          wood gas drift

Cylinder bore                                                     150 mm

Stroke                                                                  150 mm

Engine output, normal                                     32 hp vid 1 100 r/min

Birch wood, humidity 10%                               28,8 hp (on the pulley)

Birch wood, humidity 20%                               25,1 hp  (on the pulley)

Fir wood, humidity 16%                                    26,8 hp (on the pulley)

Birch wood, humidity 10%  + methanol         33,9 hp (on the pulley)

Compression ratio                                             8,2:1

Wood gas unit                                                     Hesselman T-500

Wood container, volume                                   1,5 hl

Speed with rubber wheel,

forward gear 1 to 4                                            3,1 - 4,5 - 6,9 - 14,3 km/h

Speed with iron wheel,

forward gear 1 to 4                                            2,8 - 4,0 - 4,8 - 6,0 km/h

Fuel tank                                                              75 L

Cooling system                                                   25 L

Weight, complete with wood gas unit,

filled up wood container and iron wheel        2 400 kg