Hi Hello.. I am thinking of trying to build my own garden tractor.. I am thinking of connecting two car gearboxes together for very low speeds..first gear from one gearbox onto the another gearbox.. I need low speeds.. weeds are very high..Also need to push pull things around.. { tree branches cement blocks carry bricks,etc,,etc,,, As for the mower system all good there.. I have 2 from which to adapt.. As for the diff not a problem to cut one down.. steering also not a problem have many old car wrecks too choose from ..My problem is my engine still spins too fast.. I need to reduce rpm... Also i need a good clutch system.. Belts will probably burn out too quick.. Any ideas????.... All drive from engine to gear boxes will be done with very heavy duty cogs and chain.. All got from when i worked at a foundry..
Am i crazy thinking thus???...
- Thread starter ALFA156
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gladehound
Veteran Member
There is a fine line between crazy and genius - the two being separated by ability.
quicksandfarmer
Elite Member
Power is torque times RPM. If you keep the same power at lower RPM then the torque goes up. It's likely you're going to overload the second gearbox by subjecting it to more torque than it is designed to take.
k0ua
Epic Contributor
Glade, you said quite a lot there. I like it.
ishiboo
Platinum Member
Not crazy at all... the Ford n-series and similar tractors had several aftermarket second and even third gearbox options to get the necessary ratios for work like tilling, high-speed road transport, etc. There were step-up, step-down, and combination gear boxes.
Billrog
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A fella here use to make small cats he used 2 Datson trans missions one mounted forward and 1 backwards he said for gear reduction. I don't know anything about it except what he told me he did. O do know he sold at least 1/2 doz. of them.
dickfoster
Elite Member
Rock Crawlers stack transfer cases all the time to get taller gears. I have what we call a crawl box in my truck, (the gear reduction part of another transfer case) feeding the regular 2 speed case, so with my five speed tranny, I have 20 forward gears and four reverse gears to choose from. I know one guy who has stacked transmissions. I think a 3 speed and a 4 speed, plus the 2 speed transfer case. He has lots of gear choices to choose from. So far he hasn't broken anything.
/pine
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Not a tractor per se but I know a guy that built a skidder exactly that way...that was 40+ years ago and the skidder is still working fine...!
fidowanttobe
Platinum Member
Years ago a local "crazy" did this with Subaru drivetrains for 4x4. LOTS of tinkering but they were pretty cool. Wouldn't this be a modern day Doodlebug?
Ages ago it was done all the time to make farm equipment.
Worked on a farm with a gadget made from an old school bus that had (3) 4-speeds in it. The original flathead 8 was toast, but was left in as a way to mount the 1st trans. Input power was from a 16hp one-lung Wisconsin with a 6:1 gearbox, with a double pulley. Two "B" belts were run from there down to the original crank pulley on the original motor, now without pistons. This was used to haul around 20 pickers and handlers and a few tons of produce at a very slow walk, up to a medium walk as the vines were picked out toward the end of the season. Whenever possible, the engine was kept at whatever idle that would keep it from stalling to minimize fuel consumption. It replaced a briggs 8hp, also with a gearbox that would also do the job, but at half throttle or more and so used more gas doing it, as well as breaking down more often.
All this to say that 8 to 16 hp, geared down, can do quite a bit of work.
You didn't say if you were planning to reuse the car motor or go with a small engine. If a car engine, I'd be leery of anything much over 2L as being way overkill and capable of breaking parts. Even with a smaller motor, I'd be tempted to add a belt-driven governor both to make the tractor more useful for operating, and to keep you from the temptation to apply a lot of power and break parts.
If using a small engine, don't forget that you can apply more reduction in the first stage of the belt into the first transmission. If you use a "B" section belt like a riding mower uses (except yours will likely be shorter), especially one of the kevlar wrapped ones, you will likely be able to handle most of what any reasonable sized small engine can put out. A lot of the adaptation will get simpler if you use a small engine and a belt drive/belt clutch.
You mentioned mowing. Did you intend to have a "real" PTO, or a mower with its own engine, or were you thinking of ways to drive the PTO from a separate clutch off the "front" of the engine, so you could stop the tractor while the mower "chews through" whatever it was working on? Did you have plans for some sort of overriding clutch, like the 8n/9n guys use, to keep the flywheel effect of the mower from pushing the tractor through the PTO driving the gearbox even after the motor is clutched out?
Just how much thought have you put into the other adaptations that are needed to go from just moving people around briskly to operating implements at a slower pace, besides just slowing the machine down?
Worked on a farm with a gadget made from an old school bus that had (3) 4-speeds in it. The original flathead 8 was toast, but was left in as a way to mount the 1st trans. Input power was from a 16hp one-lung Wisconsin with a 6:1 gearbox, with a double pulley. Two "B" belts were run from there down to the original crank pulley on the original motor, now without pistons. This was used to haul around 20 pickers and handlers and a few tons of produce at a very slow walk, up to a medium walk as the vines were picked out toward the end of the season. Whenever possible, the engine was kept at whatever idle that would keep it from stalling to minimize fuel consumption. It replaced a briggs 8hp, also with a gearbox that would also do the job, but at half throttle or more and so used more gas doing it, as well as breaking down more often.
All this to say that 8 to 16 hp, geared down, can do quite a bit of work.
You didn't say if you were planning to reuse the car motor or go with a small engine. If a car engine, I'd be leery of anything much over 2L as being way overkill and capable of breaking parts. Even with a smaller motor, I'd be tempted to add a belt-driven governor both to make the tractor more useful for operating, and to keep you from the temptation to apply a lot of power and break parts.
If using a small engine, don't forget that you can apply more reduction in the first stage of the belt into the first transmission. If you use a "B" section belt like a riding mower uses (except yours will likely be shorter), especially one of the kevlar wrapped ones, you will likely be able to handle most of what any reasonable sized small engine can put out. A lot of the adaptation will get simpler if you use a small engine and a belt drive/belt clutch.
You mentioned mowing. Did you intend to have a "real" PTO, or a mower with its own engine, or were you thinking of ways to drive the PTO from a separate clutch off the "front" of the engine, so you could stop the tractor while the mower "chews through" whatever it was working on? Did you have plans for some sort of overriding clutch, like the 8n/9n guys use, to keep the flywheel effect of the mower from pushing the tractor through the PTO driving the gearbox even after the motor is clutched out?
Just how much thought have you put into the other adaptations that are needed to go from just moving people around briskly to operating implements at a slower pace, besides just slowing the machine down?