Oliver Hart Parr CROSS-MOTOR-Baureihe
2 models in this series
Oliver Hart-Parr Cross-Motor range – transverse-engined tractors from Charles City, Iowa: 18-36 G and 28-50, 27.2 to 37.5 kW, 800 to 850 rpm, kerosene and petrol operation
Hart-Parr of Charles City, Iowa, is credited as one of the originators of the term 'tractor', which the firm coined in its advertising from 1907. The Cross-Motor range denotes the Hart-Parr tractors built from 1918 to 1930 with the engine mounted transverse to the direction of travel; in 1929 Hart-Parr became part of the newly formed Oliver Farm Equipment Company. Model designations such as 18-36 G and 28-50 follow the two-figure convention then common in the United States, naming drawbar and belt horsepower.
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The register lists here 2 versions with 27.2 to 37.5 kW from two- to four-cylinder engines of 8,210 to 11,064 cm³, an unladen weight of 3,323 to 4,715 kg, a length of 3,353 to 3,581 mm, a width of 1,854 to 2,235 mm, a height of 1,549 to 1,638 mm and a rated speed of 800 to 850 rpm.
These slow-turning large tractors were used for ploughing and stationary belt work, such as threshing, on the grain farms of the American Midwest, running on kerosene, paraffin or petrol, the cheaper fuel of the pre-diesel era.
On these nearly century-old machines, the condition of the plain bearings, magneto ignition and cooling system matters, along with cracks in the cast-iron frame; spares come almost exclusively from collectors, tractor clubs and specialist restorers, as no factory service remains.
Sources: SpecCodex register, model data: Oliver Hart-Parr Cross-Motor-Baureihe
Models
Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.
