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The Story Behind Deere’s First Diesel Tractor
In 1935, John Deere’s management received a wake-up call when its chief competitor, IHC, introduced a diesel tractor, the model WD-40. Deere dealers, fearful of losing sales to this more powerful tractor, were clamoring for a response. Deere characteristically responded by carefully and methodically taking 14 years to design an engine true to its two-cylinder roots.
Who could blame the company? Deere’s large-block two-cylinder gas tractors were powerhouses, turning out very respectable torque in the field. Nonetheless, farmers were quickly warming to the low cost of diesel fuel and envied the high torque of the engines that burned it. So as early as 1936, Deere’s chief engineer, Elmer McCormick, assembled a team to design a two-cylinder diesel.
how to get it started?
At first, those engineers worked on a procedure to start the engine on gas. It ran on that fuel until the motor warmed up sufficiently to combust diesel. They dropped that concept, though, exploring a 24-volt starter to spin a high-compression engine fast enough for ignition. In the meantime, they toiled over different combustion chamber designs that would deliver high enough compression to ignite diesel.
By the mid-1940s, the basic engine platform had been set, and Deere engineers found solutions to the starting issues. Taking a lesson from Caterpillar (which introduced the first successful diesel in 1931), Deere opted to employ a starter (or pony) gas engine to spin the diesel over.
The result of 14 years’ toil was realized in the model R in 1949. The diligence Deere engineers put into their diesel paid immediate dividends when the R set fuel economy standards at the Nebraska Tractor Test. The tractor was a beast at lugging a load, developing 45¾ drawbar hp.
The R received much acclaim for being Deere’s first diesel. Yet, it was also the first Deere equipped with a live independent PTO and the first to offer an optional factory cab.
The R certainly was popular with farmers. In production for just five years, the R racked up over 21,000 units sold. True, those numbers pale next to the model A, whose sales topped 320,000.
Deere management realized that the R represented the future of tractor horsepower. So much so that it was replaced by not one, but two models: the 70 and the 80. The 70 Diesel hit first, in 1953, and before production of the R ceased. The significance of this introduction lies in the fact that the tractor was Deere’s first row-crop diesel.
In the 70’s belly nestled a 376-cubic-inch two-cylinder diesel even more fuel-stingy and powerful than the R. When it was tested at Nebraska, the model 70 established a new fuel-economy record (beating the record set by the R) while recording a 51½ hp. drawbar pull.
Next came the 80
The 70’s big brother, the model 80 Diesel, hit the market in 1955. It incorporated many of the popular features introduced on the 70 such as the Powr-Trol hydraulic system, independent PTO, and power steering.
The 80 Diesel was in a class by itself, though. Capable of pulling a 21-foot disk, this green beast delivered a third more power than the R, generating 57½ drawbar hp. Both the 70 and 80 had updated pony engines. Gone was the R’s two-cylinder unit, replaced with a four-cylinder (V-formation) motor.
True to Deere form, the 80 Diesel established a new fuel economy standard when tested at Nebraska, topping its little brother’s record.
Deere may have taken its time developing a diesel tractor, but by the 1958 introduction of the models 730 and 830 Diesel, the company’s course was well set as a diesel-engine tractor powerhouse.