The Story of the RTX547

In a previous issue of Green Magazine, a reader asked Mr. Thinker what engine was installed in the Case tractor that Deere used to test the farmers’ horsepower preferences. Let’s back up a little and tell more of the story.

Whether fact or legend, a Deere vice president is said to have asserted, after first seeing the new model “R,” that any larger tractor would have to be on tracks, so it is no surprise that when they started working on what would become the New Generation tractors in the early 1950s, Deere engineers weren’t sure what size tractor farmers would be ready for. To find out, Deere engineers put together a 720 with high compression cylinders to run on high octane gasoline, a model “R” they cranked up to more than 100 horsepower and an “LI” Case with a torque converter and 4-71 Detroit Diesel engine.

The whereabouts of the 720 are unknown. Most likely, it was either scrapped or sold as used and it didn’t take long for the crankshaft on the “R” to break and destroy much of the tractor in spectacular fashion. The Case “LI,” though, is alive and well and resides in the collection of Darrel Fischer of Watseka, Illinois.

According to Mr. Fischer, who has spoken to several engineers involved in the project in the 1950s, the “LI” was chosen because at the time it had the heaviest drive train. Perhaps that is why a company in Oklahoma was already building the parts necessary to install a Detroit engine in these tractors. With larger injectors, the engine produced slightly more than 100 horsepower.

The tractor was painted army green and taken to large farms in the western United States, always concealed with a tarp, where farmers were asked to hook it to their largest implement and then give Deere engineers their impressions. In many cases, farmers were able to pull their implements twice and sometimes three times as fast as they had been previously. From the information received, Deere engineers came up with their target horsepowers for the new tractors.

When testing was completed, the “LI” with the Detroit Diesel engine, known to the engineering department as the “RTX547,” found its way to Deere’s factory at Waterloo, where it is remembered as having been used to occasionally move equipment around. From there, though, the trail goes cold for quite awhile although Darrel Fischer guesses that it was eventually sold to a scrap yard, where someone decided to sell it as a whole tractor rather than as parts.

Fischer spied it at a consignment sale only about five miles from his home in central Illinois. It apparently wasn’t the first time the tractor had stood at auction, but a problem with the throttle linkage had kept it from starting and made it a difficult sell. After getting it home, Fischer soon found the problem and started the tractor. Several former Deere engineers inspected the tractor at the Chillicothe, Illinois tractor show in 1996 and found several indicators that proved this tractor to be the “RTX547” they had worked with some 40 years earlier.

That’s the story of the Case tractor that was instrumental in the development of the New Generation tractors that so many people use and co