My Father Duane bought a brand new Cub Lowboy with a belly mower to mow his acreage back in the late seventies. I recall going home and looking it over and thinking with my background as an auto tech I should be able to build one similar using cast off auto parts.
This write up details the following build which after a long crooked road gave our family a little home-built which has done everything we have asked, and more. No project I have been involved in has gave more satisfaction, a better return on the time and money spent.
Some of the parts used are no longer readily available making an exact copy difficult to build. Some of the ideas though I hope will spark interest and get your head thinking, yes, I could build that, I could do that. Hang on, here we go.
I first thought of using a 1600 CC Datsun L-16 engine from an early Datsun pickup truck. I was familiar with the motor and they were very available all the body's having rusted off them. The problem, one you will run smack into, is they are too long. Not the motor itself but the package. Almost all rear wheel drives setups like this have a long tail-shaft on the transmission. This would not be so bad but you need to slow the speed down which calls for a second transmission. Add the second transmission and you now have the engine perched way up front hanging out over the front tires while the back transmission is under your butt with the differential flipped around so the input shaft is pointing backwards driven with a chain off the second transmissions tail shaft.
A spare 84 Nissan transfer case.
In short a cobbled up mess. One day I was looking under the hood of a customers little Nissan Sentra, 1984 or so, when it the solution struck me. If I used a front wheel drive power-train all the length problems were resolved. Pay attention here as this is the key to the build.
The little five speed manual trans-axle not only has the five speeds, and reverse, but a further 3.5 to 1 reduction gear set after the five speed, all this built into one very compact case, no long tail-shafts. And hang on, it just keeps getting better. In the Sentra, as in most front wheel drive cars the engine sits sideways the driveshafts sticking out to the right and the left going directly to the front wheels.
What if we turn the engine 180 degrees so the front of the engine points to the front the axles now pointing to the front and the back? And what if we take the trans-axle apart and weld up the spider gears in the differential so we can throw the back drive shaft away? What is left is one CV shaft pointing forward running along the right frame to the front of the tractor.
Now to take this geared down power source and direct it to the back axle where we need it. The 1984 Nissan 4WD pickups incorporated a divorced transfer case. Rather then hanging off the back of the transmission these units were frame mounted and had flanges to which were bolted three separate shafts, one in and two out. Taking one of these units and bolting it to our frame right in front of the engine we can hook our output shaft from the trans-axle to the input and use the flange that formerly drove the front axle of the pickup truck to power up our rear end though a driveshaft which passes right under the engine.
And that is the breakthrough without which our little home-built would be a cobbled up mess. What this shortened set up allowed us to do was locate the engine and transmission where it best fit the build. I was able to have it on temporary mounts I could slide up and down the frame. This lets you locate your seating position and slide the power-train unit forward and back until it sits right where wanted.
My plans for this story include pictures of individual projects involved, the steering, the differential used, the wheel adapters, fenders, power steering, hydraulics, front axle, ect..along with some account of how problems were met and resolved. For now though a account of how the tractor has performed.
What we ended up with, a five speed manual with high low range. Power steering, small separate pump for hydraulics. A simple hoist or cherry picker off the back of the tractor capable of lifting a small block Chevy with heads. The cherry picker is also used as the lift for the three point hitch.
Our little tractor has been up and going for nearly 30 years now. It has held up surprisingly well. Several years ago we replaced the clutch due to its slipping. If was not for doing some tractor pulling I am sure our original would still be in place. One other failure is the spider gears in the nine inch Ford differential would shatter every time we got into a hard pull on a tacky pulling track. We put in a unit with an extra set of pinion gears in it to resolve this issue. During normal use we just have not seen any breakage. I thought the welded spiders in the little five speed trans-axle, the ones welded up, would be the weak link, they have never been an issue.
The first five years the home-built was used to mow grass. Took an old five foot Arts-Way PTO finish mower and modified it to be driven with a 16 horse Briggs Van Guard engine. It was a little awkward around trees and obstacles but was much faster than what we had before. County fair time we put a straight pipe on and go tractor pulling. We run the 3000 and 3500 lb classes. On a good day we can beat a B John Deere. Wind it up, slip the clutch, get it going and then hammer down. Not really competitive we do make lot of noise and have a lot of fun.
With a front mounted boom and rear mounted tank it is our chief spraying tractor. We have one small pasture and about ten residential yards to spray each year. We now have other tractors but the home-built works best for spraying. A bonus is the heavy duty flat top fenders. In the pasture spot spraying thistles with the hand wand you can stand on them to get a little more distance and better see what is out there.
How does it drive? As Bob Dylan would say, “Smooth as a rhapsody.” Honestly it drives like a dream, best part of it. We have a nice little Kubota L3000DT. About the same size as the home-built it has ag tires which are rough on smooth roads. The 3000 tops out at maybe twelve MPH. A four speed with hi/low range you have to pick your gear before starting out as the gears are not synchronized.
Our little home-built has relatively smooth tires on it giving a nice quiet ride. All five gears are synchronized so shifting is smooth. Fifth gear hi range our home-built will run along nicely at about twenty or so. Feel racy you can open it up and it will run just over fifty. You can accomplish almost anything you wish to do in high range, dropping it into low will slow all gears by about one half. We do all our pulling in low range, second gear. Great traction, getting stuck has never been an issue. We do have a set of chains for the rears, they certainly take the smooth out of it.
Not what it was built for but what our little tractor is best for is after supper summer tractor rides. With plenty of gravel roads and quiet black tops available here in north west Iowa my Grandson Evan and I, we have put in side by side seating, enjoy taking it out for spins. We often go ten or even fifteen miles out just poking along and enjoying the sights and feel of an Iowa summers evening. For this task it has no equal, way better than a motorcycle or side by side.
As mentioned I will be following up
with some pictures and details of the build. In the meantime I hope
this has got your interest up and your brain to thinking about what you could build.
A link to a video explaining our tractor.
https://m.youtube.com/watch?v=rWrNm9uKWs8&t=15s
Video to a short run down the road.
https://www.youtube.com/watch?v=dHVhtQNVnVQ&t=5s
