Alternative Fuels in Early Farm Tractors

Alternative fuels have long tradition as ag cost-cutter


| July 2013



Massey Ferguson Super 90

Recently purchased in Texas, this rare Massey Ferguson Super-90 high-clearance tractor is now part of the author’s collection.

Photo By Chuck Lyons

Steam tractors could be described as the ultimate in alternative fuel tractors. They’d run on almost anything that would burn, including wood, sawmill slabs, sawdust and shavings, “hog” fuel, coal, coal slack, kerosene, oil, heavy oil and even straw (the burning of which was highly developed and quite popular out West from the late 1890s through about 1915).

But for all that versatility that lowered a steam engine’s fuel cost, other operational costs far overshadowed those savings, so when internal combustion engine tractors achieved reliability, steam tractors quickly faded into obsolescence. The internal combustion engine has ruled the ag power market ever since, but not always as a gasoline burner.

By 1910, refining technology still produced only a limited yield of gasoline from crude oil, and its growing demand as automobile fuel kept gas prices high compared to that of kerosene and heavier fuels. For that reason, many early tractor operators, particularly those with large machines, searched for tractors capable of consuming heavy, cheaper fuels. Efficient kerosene burning made for great advertising copy; just look at Rumely OilPull ads from that era.

Kerosene

At first, the most common alternative fuel was kerosene, which was produced from both crude oil and coal. It cost a fraction of gasoline yet, when burned efficiently, produced approximately the same horsepower hours per gallon as gasoline. (Horsepower hours/gallon is a fuel conversion efficiency value that eliminates engine size from consideration, thus making the result from a 100 hp engine comparable, straight across, to one from a 10 hp engine.)

But kerosene has its drawbacks. Mainly, it does not vaporize as readily as gasoline, and it has a much lower octane content. That usually meant intake air and the intake manifold had to be heated to improve vaporization, the combustion chamber had to be carefully designed and kept clean to prevent knock, and for some engines (Rumely OilPull and the early John Deere D, for instance) water was injected into the cylinders to moderate combustion so as to further prevent combustion knock. These engines do not “burn” water, as some people think. The addition of water merely moderates the combustion rate to reduce knock and prevent engine damage. The trade-off, though, is that water injection reduces overall engine efficiency.

Each solution to these fuel considerations came with its own drawbacks, increasing engine complexity and requiring more skill and attention from the operator. As oil-refining technology improved, gasoline yield increased and gasoline prices fell in comparison to prices for kerosene and oils. Soon, the extra complexity of operating on kerosene no longer made sense financially, and kerosene faded as an ag fuel.