# EV Tractor Ford 9n Conversion



## Murphree (Apr 17, 2018)

I've been a member here for a while but typically just browse classifieds here and post to youtube/facebook. 

It's a baldor 6kw motor and a curtis controller (but I'd love to replace it with a soliton jr). Batteries are 21s8p nissan hybrid pull outs. Motor is direct drive clutchless. Lift arms are driven off pto so it can be raised in neutral or while driving. I get a couple hours of utility chores out of it. 










Here's a video link to the walkaround of my tractor.


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## remy_martian (Feb 4, 2019)

Nice. 

How did you couple the motor to the trans input shaft?

Is the 8N a single or dual clutch?


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## Murphree (Apr 17, 2018)

It's a single clutch. I cut the rivets off the OE 1940s clutch disc and has a 1" shaft adapter to 6 bolt adapter that came with the forklift engine. The holes were close so I milled the clutch disc about 0.080" oval outwards and wahala, bolted right up.


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## remy_martian (Feb 4, 2019)

Going to put the 8N bodywork back on?


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## electro wrks (Mar 5, 2012)

View attachment 121043



Murphree said:


> It's a single clutch. I cut the rivets off the OE 1940s clutch disc and has a 1" shaft adapter to 6 bolt adapter that came with the forklift engine. The holes were close so I milled the clutch disc about 0.080" oval outwards and wahala, bolted right up.
> View attachment 121045


Do I hear a lot of gear/spline grinding noises in your video? This tractor has a pilot bearing on the transmission input shaft so it probably needs careful support and alignment of the motor shaft rotational axis and the input shaft rotational axis. Usually, no more than ~0.005" misalignment is allowed by factory specs. Without this proper support and alignment, gears, bearing, and splines can get damaged.


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## Murphree (Apr 17, 2018)

remy_martian said:


> Going to put the 8N bodywork back on?


Yes. It looks good with it but I got a better set of hood sides and am working through a safer tilting mechanism. Because theres no tank it all tilts forward.


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## Murphree (Apr 17, 2018)

electro wrks said:


> View attachment 121043
> 
> 
> Do I hear a lot of gear/spline grinding noises in your video? This tractor has a pilot bearing on the transmission input shaft so it probably needs careful support and alignment of the motor shaft rotational axis and the input shaft rotational axis. Usually, no more than ~0.005" misalignment is allowed by factory specs. Without this proper support and alignment, gears, bearing, and splines can get damaged.


And I'd tend to agree with you, but this old ford does not have a Sherman transmission or anything in the trans tunnel. The input shaft can be moved by hand over 1/2" from center in any direction. I built the mount for the most likely to be center position. I ran my soliton1 at 200v 1000a thru this setup for fun and it held. I think its just that these old tractors are noisy and its usually covered by the sound of a gas engine.


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## electro wrks (Mar 5, 2012)

Murphree said:


> And I'd tend to agree with you, but this old ford does not have a Sherman transmission or anything in the trans tunnel. The input shaft can be moved by hand over 1/2" from center in any direction. I built the mount for the most likely to be center position. I ran my soliton1 at 200v 1000a thru this setup for fun and it held. I think its just that these old tractors are noisy and its usually covered by the sound of a gas engine.


I like the look! Can you post some closeups of the adapter plate and support beams that tie the transmission casting and front axle together? Some people may not realize the original engine in this tractor, and many other tractors, is a fully stressed member tying the two together. It's the same basic design used with the rear axle and engines in F1 cars! This is a spot where you want minimal flexing from the large loads imposed by forces on the front and rear axles. The flexing messes-up the alignment of the transmission input shaft and the electric motor shaft. As mentioned before, this could damage gears, bearings, and splines.
The 1/2" play in the input shaft is a good indicator that it needs to be well supported and located, as with the original pilot bearing mounted in the ICE flywheel. " [M]ost likely to be center position", as you write, may not be enough to achieve this. This said, I've had repair work customers, with tractors like this, grind away with their damaged and worn-out transmissions for decades. It just sounds really bad, and can't be doing the gears, bearings, and splines any good!


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## Murphree (Apr 17, 2018)

Here's the best picture on have before it was final welded. Motor is 120lb. Bellhousing and front axle plate are 3/8" thick. Sides are 4x8x0.5". It survived a big dropped off the jack test.


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## remy_martian (Feb 4, 2019)

There's no "flexing" in a tractor. With a counterweight on the 3pt hitch, you could walk behind it with no front wheels at all.

The way he has mounted it on the flange, all torque is through that massive trans/diff casting and the only reaction forces are though the two back wheels via the wheel bearings. This is why tractors can get away with a pin in the middle of a beam front suspension. 

The only loads on that massive angle iron that he has are beam loads from the battery pack, and half of those go through that suspension pin. In fact, if it's going to break, it'll be from the wheelies, which can break the axles in a totally stock tractor and the axles or the pin might break well before his welds do.


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## electro wrks (Mar 5, 2012)

Tractors flex and break in half all the time, usually related to too big or overused attachments. Or, running at too high a speed over rough ground(OK, and wheelies): $27,000 tractor 'broke in half the first time I used it' 
Or, this one:









This youtube from Messicks explains the problem at ~1:00 :






It looks like Murphree has anticipated this with a heavy cross section steel beam structure. The beams are also well attach to the adapter plate near the existing mounting bolts to minimize flexing and potential cracking.


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## remy_martian (Feb 4, 2019)

That John Deere broke the torque tube from torque flexing. Totally different than the structure we are talking about here.

The electric motor is mounted to the bell housing. Forces are shear in a massive adapter plate and applied at the bell housing bolts, which are on a large radius.

There is zero torque ahead of the bell housing face the way the motor is mounted.


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## Murphree (Apr 17, 2018)

Yeah I totally lucked out with that flange and included bearing so I utilized it the best way I knew. If you look hard enough you can see where I I the existing 1/4" thick forklift bracket and welded it to the 3/8 bellhousing plate. I also prioritized spline engagement which wound up costing me some spacing as seen by the washers. Eventually I'll make a proper plate but it works well as is. If anything I'm afraid I over built the motor mount and the cast iron is now the weak link. 

I agree alignment could probably be improved but I dont know how. I used the existing engine block by clamping it to the 3/8 plate and then used transfer punches and calipers to locate the holes.


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## electro wrks (Mar 5, 2012)

Murphree said:


> I agree alignment could probably be improved but I dont know how. I used the existing engine block by clamping it to the 3/8 plate and then used transfer punches and calipers to locate the holes.


Proper alignment is going to be difficult without a machined concentric cylindrical surface as a guide, like on the older detached auto bell housings:






One cylindrical surface that may be concentric with the transmission input shaft rotational axis is the long tube the clutch release bearing slides on. Unfortunately, it may be difficult to figure out if the OD of this tube is concentric with the shaft rotational axis.
If you want to try it, you could machine a temporary sleeve that fits on the OD of this tube with the other end of the sleeve bored or machined to closely fit on the motor output shaft or some other cylindrical concentric surface on the motor. The bearing bore on the temporarily removed end housing of the motor could be another surface. You'll need to make sure no weight of the motor is hanging off the sleeve that could throw off the alignment. Once the alignment is setup, register it in place with drilled and reamed dowels(ideally). Or, you might get away with carefully done scribe marks to position the adapter plate(s) and motor.


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## Murphree (Apr 17, 2018)

I'm familiar with dial indicating bellhousingsusing offset pins, but this is not that. The input shaft with throw out bearing tube you speak of is what moved wildly at the engine location. Using your methodology would not locate the the input shaft centrally. The only way to get close is using the existing engine block and crank location in this application. Luckily it only sees 200kw on occasion. 😁 considering I'm $1400 into the entire project, I can go flick switch, and it exceeds my expectations every time I've used it... I'd say I'll keep using it as is.


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## electro wrks (Mar 5, 2012)

Murphree said:


> I'm familiar with dial indicating bellhousingsusing offset pins, but this is not that. The input shaft with throw out bearing tube you speak of is what moved wildly at the engine location. Using your methodology would not locate the the input shaft centrally. The only way to get close is using the existing engine block and crank location in this application. Luckily it only sees 200kw on occasion. 😁 considering I'm $1400 into the entire project, I can go flick switch, and it exceeds my expectations every time I've used it... I'd say I'll keep using it as is.


That tube should be rigidly attached to the front face of the transmission. It might be broken or worked loose at its flange, or the attaching bolts loose.


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## remy_martian (Feb 4, 2019)

200kW is a metric a$$load of HP on a small tractor, lol. An 8N is 20kW on a good day, isn't it?

If you're using that 200kW motor rated at like 9000 RPM, then you'll actually be close to 40HP at 1800, which might still bust stuff in the driveline. I'd keep the current within the limits of the original engine, other than the occasional wheelie for fun.

I'd put a ROPS on that thing as well. Doesn't take much of a ground hog berm to kick it into flipping (don't ask how I know this...).


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## Murphree (Apr 17, 2018)

Yeah it usually stays on the 88v "400a" controller but i've never seen more than 150a through the curtis so practically it's only ~18hp which is plenty to pull a cultivator or massive logs. The soliton1 200v 1000a was just for fun and an anticipated tractor pull that was cancelled due to covid. The big wheelies I did had a cultivator digging in the ground for at least a tiny amount of rollover protection. FYI the weight of just the rear tires is est 350lb/ea and you can see it spinning those almost instantly in the dirt. I think a good balance would be run the Soliton Jr at 88v 600a. 70hp would still be well into hot rod tractor category, practical for chores, and enough power for the goofing off like a tractor pull. I built a pulling hitch for it and I think I'll add some ROP to it like many other pulling hitches.


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## remy_martian (Feb 4, 2019)

Quickest way to decapitation is snapping a tow cable, so don't pull anything that doesn't have a tongue on it.


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## Murphree (Apr 17, 2018)

Quickest way to decapitation is probably insulting the wrong blokes religion! 

ROP is an acronym for rollover protection. Anything I pull without a tongue is with 3/8" chain like when pulling logs.


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## electro wrks (Mar 5, 2012)

remy_martian said:


> That John Deere broke the torque tube from torque flexing. Totally different than the structure we are talking about here.
> 
> The electric motor is mounted to the bell housing. Forces are shear in a massive adapter plate and applied at the bell housing bolts, which are on a large radius.
> 
> There is zero torque ahead of the bell housing face the way the motor is mounted.


RM, how do you know the JD failure in the picture was from " torque flexing", after you wrote that there was "no "flexing" in a tractor"? Are you referring to the torque required to move the tractor forward and reverse? Most of that torque is developed in the differential bevel gears and, usually, and sets of final drive gears near the wheels. Only a fraction of the wheel torque is transferred through the cast frame of the tractor to the transmission(s) and electric motor or ICE. A more likely failure scenario is from mostly a bending load from overloading a loader attachment on the front of the JD and something counterbalancing the load, mounted on the back of the tractor. This is explained in the video from Messick's.

Again, as I wrote before, my initial concerns were that these bending loads applied to the relatively thin 3/8" thick adapter plate, would cause it to flex and misalign the electric motor relative to the transmission input shaft. I write "were" because Murphree has carefully lined-up the ends of his large steel beam structure, where it attaches to the plate, close to the mounting bolt holes on the tractor's bell housing. This minimizes the flexing of the plate. Good job Murphree!


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## LrBen (Dec 30, 2017)

That's a great build. Really enjoyed the videos as well. The world needs to see more EV tractors like this.


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## Murphree (Apr 17, 2018)

Thanks! It's certainly not perfect but it's handy to have around the yard and I've learned a ton. I did manage to score a soliton Jr motor controller for it and have decided it'll ultimately need a BMS. There will be more videos!


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## Murphree (Apr 17, 2018)

Quick update to this thread and current tractor status. Managed to buy a SolitonJr controller and have been running the tractor at 28s4p happily for some time now. Despite neglect and abuse, the setup continues to work every time I need it. Ironically, the battery giving me the most issues are the 12v lead batteries that run the motor controller. I manually disconnect after each use but cannot find a good quality lead battery. I suspect a high-quality DCC converter would be ideal, but I'll wait until I eventually upgrade and go to a simpler battery pack before trying to get some silly 103.6vdc to 12vdc controller.


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