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Pneumatic Shift Added To Vintage Versatile
While rebuilding the engine on his 1974 850 Series Versatile tractor, Jim Hermanski, Enid, Okla., decided it was time to do something about the old tractor's inherent shifting problem.
  "These are great tractors, and their 3-speed transmissions with four ranges allowed them to be used for a wide range of field work," Hermanski says. "The problem was that after you'd used the tractor a little, the remote shifter box wore down and it was hard to keep it from shifting into two gears at once. All the Versatiles with this transmission are notorious for this."
  Having lived with the problem since he bought the tractor used in 1978, Hermanski had given plenty of thought to a solution.
  "I worked for years as a truck mechanic," he says. "A lot of trucks with that same engine had pneumatic shifters, so I decided I could put one on the tractor and solve the problem."
  His first step was to hunt down a used air compressor and an accessory drive assembly that had been used on the same model Cummins engine in an over-the-road truck.
  "The Versatile engine was exactly the same as the truck engine, so all the mounting holes were already there. All I had to do was put it in place and add a coolant line to keep it cool," he says.
  His idea was to replace the manual transmission shift lever with small pneumatic cylinders that would shift the gears. "I worked for an International Harvester truck dealership here in Oklahoma, and we worked on a lot of oil drilling equipment," he says. "So I was acquainted with a type of air spool valve used to control the pto on drilling rigs. They're small cylinders with a very short stroke."
  Hermanski decided on some dual cylinder spools that had been used on a Speed Star transmission. They have buttons on them to control the rams. Since he was replacing the floor shifter (three forward speeds and reverse), two dual blocks were enough. He bolted the two blocks together, allowing him to shift using just four buttons.
  "When all four are down, it's in neutral. Then there's one button for reverse and one for each of the forward gears," he explains.
  "There's a clevis on each end of the pneumatic cylinder. One end hooks to the shift lever and the other to a stationary point, so I had to build stationary pivot points on the tractor frame for the rams to hook to. On the top shifter, I had to build a bracket that came off the side plate of the transmission. And I had to match the angle for the neutral position on the shifter. It took a little designing to get the stationary points made, but it wasn't that difficult," he says.
  "I figured I'd have to make new levers on the transmission to get the stroke right, but the ones that were on it worked just right," he continues.
  He found all the parts he needed (except for air lines, which he purchased new) at Southwest Truck Supply, Pratt, Kansas. "I had to rebuild the spool blocks and, because they were old, I went through several before I could get two that would seal up tight.
  "What took the most time was running the air lines. I think there were 10 of them in all," he says.
  "You still have to use the clutch to shift gears. And if you happen to pull up two buttons at once, it'll still shift into two gears," he says. "But it doesn't jam that way. All you have to do is push down one of the buttons and it corrects itself."
  Contact: FARM SHOW Followup, Jim Hermanski, RR 6, Box 320A, Enid, Okla. 73701 (ph 580 234-0016; email: jimhermanski@hotmail.com).

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2005 - Volume #29, Issue #4