Extra Engine Converts Combine To 4WD

Extra Engine Converts combine to 4WD COMBINES Conversions 13-6-1 "It's great insurance for combining in mud, and it cost far less to build than any commercial rear axle drive system on the market," says Robert Greenlee, Okmulgee, Okla., who convened a 1960 Massey Ferguson 510 combine to 4-WD by replacing the rear axle with the front steering axle from a 4-WD military truck driven by an extra engine and transmission removed from a 1971 Ford Pinto car. 'The add-on engine mounts on top of the combine• behind the grain tank. A driveshaft off the transmission powers a pair of sprockets that chain-drive a pto shaft beneath the rear of the combine that drives the steering The-home-built 4-WD system operates completely independently. To switch from 2-WD to 4-WD, Greenlee simply starts the 4-cylinder, 80-hp Pinto engine and uses a separate throttle and shifter controls in the cab to control axle speed. Greenlee converted the combine in the winter of 1986-87 after a wet fall kept him out of his soybean fields. "I didn't want to spend the money on a commercial rear axle drive system so I bought a used combine to make the 4-WD conversion. That winter I used it to cut 500 acres in the mud. My neighbors couldn't believe the job it did. One custom cutter who owned a big Massey Ferguson 860 combine equipped with a Mud Hog hydraulic-assist rear axle drive system asked me to put a 4-WD system like mine on his combine. It outperforms a Mud Hog-type drive system because I can operate the rear axle independently and at any speed. On Mud Hogs the rear axle always turns with the front axle and at the same speed. Whenever I turn in mud at the end of the field, or when I come to a wet spot and the front axle bogs down, I just start up the engine and the wheels push me right through. "I use this modified combine mainly to harvest wet fields. When we have dry conditions I use a newer and larger combine. However, my modified machine does work well on dry ground and I can drive the combine without even starting the main engine by letting the rear axle provide the power. I didn't want to spend the money on hydraulic components but it would be possible to drive the rear axle with a hydrostatic motor instead of the Pinto engine for better control and an infinite range of speeds. The best thing about the conversion is that I spent about $3,500 compared to $9,000 for a new Mud Hog system. I paid $1,600 for the combine and spent about $500 to repair it. I paid $100 for the rear axle, $150 for the Ford Pinto engine and transmission, and $250 for bearings, sprockets, and roller chains. The rest of the cost was for frame-work, cables, and cab controls. The combine paid for itself the first day when I harvested 1,000 bu. of soybeans. The biggest problem is that we often have to pull trucks out of the field with a 4-WD tractor." To support the weight of the add-on engine, Greenlee welded a frame made from 1 by 2-in. sq. tubing along the sides, rear, and top of the entire rear half of the combine. He welded a sprocket to the end of the driveshaft off the transmission. A roller chain runs from the sprocket on the drive shaft to a 6: 1 gear reduction sprocket assembly half-way down the rear of the combine. A second chain runs from the gear reduction sprocket to the pto shaft mounted beneath the straw choppers. Spring-loaded idler pulleys keep the chains tight. The pto shaft, borrowed from an old self-propelled mower, is supported by a pto housing re-moved from a Minneapolis Moline tractor. When Greenlee doesn't need 4-WD, he simply removes the pto shaft. The military truck drive axle is equipped with 18.4 by 16.1 tires removed from an old self-propelled swather. He split a pair of pickup wheel rims in half and welded in spacers to widen them to 16 in. He then installed the engine throttle, shifter, ignition switch and starter in the cab. He uses the same fuel tank, electric fuel pump, and battery for both engines. Contact: FARM SHOW Followup, Robert Greenlee, Rt. 2, Box 1410, Okmulgee, Okla. 74447 (ph 918 733-2667).

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