1992 - Volume #16, Issue #2, Page #10[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story | Read this issue]
Junked Car Coils For Deere Tractor"The engine runs and starts much better than it ever did before," says Richard Nelson, Mt. Pleasant, Mich., who replaced the original coil on the 4-cyl. "pony motor" on his 1953 Deere 70 diesel tractor with four coils from junked Chrysler automobiles. The pony motor is a small V-4 gas engine used to start the tractor's 2-cyl. diesel engine.
"My Deere dealer wanted $226 for a new coil. I picked up the old car coils from my local junkyard for $5 apiece," says Nelson, who simply wired the four coils to the existing Wico "distributor", using existing points and condensers. "The only modification I made to the Chrysler coils was to remove the drop-ping resistors. (Chrysler used 6-volt coils on its cars until it switched to electronic ignition, so dropping resistors were fitted to the coils to drop voltage from 12 volts to 6. Since the Deere tractor has a 6-volt system, the resistors weren't needed for the conversion)."
"Two coils fire together, one on the compression stroke on one cylinder and one on the exhaust stroke on the other cylinder. When the opposite cylinder comes up on compression, the process is the opposite," explains Nelson, who's an aircraft mechanic and a part time farmer. He simply mounted the 4 coils on a strip of 3/16-in. thick, 1-in. wide flat stock. Then he wired the coils to the points, battery and spark plugs. "The original Wico coil is a double wound coil that fires off each end so it's like 4 coils in one. So I really didn't modify the system. It still works the same except that I'm using 4 separate coils. The benefit is that these four coils have a lot more power so the engine starts and runs better. That's because each of these coils originally ran an 8 or 6 cylinder engine but now each coil fires just one cylinder."
Nelson says the idea would also probably work on Deere 720 diesels because they're also fitted with the gas powered starting motor. "Parts are getting harder and harder to find for these older tractors so everyone's looking for ways to make do with other parts."
Contact: FARM SHOW Followup, Richard F. Nelson, 4985 West Pickard Rd., Mt. Pleasant, Mich. 48858 (ph 517 773-2369).
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