Hey all,
As I promised a few weeks ago, here's the first bit of what I've been meaning to share with the group - taking my E20 from "as found" in rough, nonfunctional shape to a good working machine, with some healthy modifications on the way. I'll write about the loader build and drum brake conversion in later emails. Photos of all this are below, and some explanation below. Note the loader build starts with the photos of cutting a chunk of metal out of the large blue box; anything after that I really haven't talked about below except for the lights.
When I got the tractor, it had been sitting for approximately 25-30 years and so the batteries were long since dead and gone. I scrounged up three marginal automotive starter batteries and used those for testing of the tractor. Testing didn't take very long because nothing at all worked except the lights - no drive power at all. I pretty quickly decided to go with a motor controller rather than have the ancient wiring potentially cause trouble time and again - assuming I could even fix it initially!
MOTOR CONTROLLER
Credit to Robert Troll on this list for providing me with advice to get started and even selling me some spare small parts for the conversion! I bought a used Curtis 1205-105 (400A) from eBay, and from my understanding a 1204 would work pretty much identically. With this in hand, I decided to gut the entire wiring of the stock tractor rather than deal with corroded connections, worn or broken insulation, mouse chewed wires, etc. Additionally, this allowed me to rewire all battery connections and the motor armature with 2 gauge wire to avoid power loss at higher amperage draws. This benefit could be debated but as I was starting from a clean slate, I felt it was worthwhile. The PTO and accessory outlets were wired with 6 gauge, and everything else (including the motor field) was wired with 14 gauge. I believe the only stock electrical parts which were reused are two contactors, the accessory breaker, the dash gauges and the key switch. Though I suppose the motor counts and the motor breakers as well.
To perform this conversion, I designed the circuit in Visio before I actually put anything in motion. This was extremely useful, and helped prevent me from making mistakes both in circuit design and execution. Below are links to the Visio file as well as a PDF for those who do not have Visio. PLEASE NOTE: I am not liable for any mistakes in this diagram nor any mistakes or accidents you may have in adopting this circuit to your tractor. It's sad I have to say this but always remember you're driving a nearly 1,000 pound machine and have a contingency plan in the case of electrical failure which causes unexpected acceleration, braking, etc.
For the new throttle control, I bought a genuine Curtis FP-6D from this site:
https://www.tecknowledgey.com/curtis-fp-6-fo-7-footpedal-throttle.html . Yes, there are knockoffs available for about half the price, but this is such a critical component I wanted one of good quality build and engineering. It wasn't worth it to me to save $70 or so and have something which could potentially fail in a way that could cause a serious or fatal accident. These throttle controls always have a microswitch to detect when the throttle is closed or has been opened. This is useful for designing a "high pedal disable" circuit meaning if a safety switch is opened or the tractor is flipped from FWD to REV, you must let off the throttle first before power will be applied to the field and the armature. Mine came wired with the opposite configuration from what I needed for the HPD circuit, but the microswitch inside had both normally closed and normally open contacts available. I opened the throttle box and simply added a wire for the other contact.
CHASSIS AND TIRES
The tractor was covered in surface rust and generally looked like heck. I didn't want a show queen but wanted something I could be proud of, so I took a hand drill with a wire cup brush and took off all the loose paint and rust. Then I hit it with rustoleum primer and rustoleum sunburst yellow (IIRC). I did all this after stripping the tractor of the wiring and all. I also painted the underside when I had the transaxle off and the front axle removed. I didn't bother to fill or patch any dents or holes so while it looks pretty good, I'm not afraid to use it.
I replaced the steering pillow block and added whatever flat and/or belleville washers I needed to get a good tight mesh of the steering gears.
The tires were all shot and the front wheels were very rusty. I cleaned them up as best I could and painted them. The rear wheels are fine but the fronts leak air and go flat over several weeks, so at some point I'll add tubes or replace the rims. I went with WDT P328 24X12.00-12 4-ply ag lug tires in the rear and Power King Straight Rib 16X6.50-8 4-ply tires in the front. Both front and rear rims are flipped to give a wider track.
The original seat was totally rotted out so I got a replacement seat from Tractor Supply. I think it was from their County Line brand and it slides back and forth which is pretty neat. It's comfortable and does the job. Though it's heavier than the stock seat, so I had to add washers underneath the spring which lifts the seat in order for the seat switch to work reliably.
FRONT LIFT TO WINCH CONVERSION
My front lift wasn't in good shape, and I figured a small winch could double as both a lift and as a way to pull things, or pull the tractor if it got stuck. The Harbor Freight 2,500lb ATV winches are cheap, readily available and come with a nice wireless feature. I wanted mine hardwired to a switch in the original location, so I took apart the original control box, removed the contactor and mounted it to my upper dash panel. I used two winch backing plates also sold by HF. The pictures show only one on the top side of the metal (at the bottom of the front battery box), but I later took it off and added a second on the bottom so the original metal is sandwiched by the heavy backing plates. The purpose of the bottom backing plate is to expand the footprint of the winch so the force is spread over a larger area. I also made a roller out of steel to replace the stock plastic version.
The winch drum is a bit off center, and I mounted the fairlead to the bumper. It's not quite ideal but it works fine. I haven't had to use it for anything strenuous, but it should hold up.
ONBOARD SMART CHARGER
I went with a Minn-Kota MK-345PC 12v 3-bank, 15A per bank smart charger. The charging amperage could be higher to meet the C20/10 rule, but all in all it works fine, it didn't cost a fortune, is reasonably compact, etc. The each bank is wired to charge two of the 6v batteries. Given the only tap I have is 12v for the winch, this works out very well and generally speaking I should not have any imbalance in discharging/charging especially because the winch is used infrequently.
You can see in the photos I mounted it to a board above the front batteries, where there is plenty of space. I did have to cut out the rearmost hood brace to accommodate the charger. I know one member on the list wasn't a fan of this charger, but I do think it's a decent value/compromise. It does get hot while charging, and knowing heat tends to kill electronics I have taken to plugging in a fan to blow on it while charging. It's on my to-do list to add a 12v fan + transformer permanently mounted in a place where it blows on the charger when the tractor is plugged in for charging.
LIGHTS AND OTHER MISC ELECTRONICS
There are myriad different kinds of 12v LED vehicle and work lights available from HF, Amazon, and other retailers. I got a rectangular kind and after removing the end caps and doing some cutting they fit pretty well into the stock headlight openings. I got a third light of a similar kind and mounted it to the back of my seat. All three lights are wired in series and draw approximately the same amperage so each light sees approximately 12v. I don't use them too much, but they are nice and bright and good to have when I need them. I recommend the rear work light because with all three on you get pretty good illumination all around.
I got panel mount LEDs to use as FWD (green) and REV (red) indicators. They are powered by the field voltage and the appropriate LED lights up based on the polarity sent to the field. I had to add resistors in series with these LEDs but even so one of them burnt out and had to be replaced. It's been close to three years since I set this up, so I don't quite remember the details. It's not happened again, yet, but I'm probably overdriving the LEDs to some degree.
The main disconnect was replaced with a modern version. I recommend this as any resistance here is needlessly wasted power. I did have to drill out the hole to fit the new disconnect and IIRC I used a tri-flute bit meant for tile or something which I bought at Home Depot. I wanted something with 3 or more flutes so it would self-center in the existing hole. Drilling this on the drill press or milling machine wasn't feasible and using such a big 2-flute drill in aluminum with a hand held drill is going to be painful.
The PTO and accessory outlets were replaced because they are cheap and the original ones were likely corroded on the interior contacts. The seat switch was also replaced with a new one.
Once the tractor was proven and working I replaced the starter batteries with six proper 6v golf cart batteries. I made all the jumpers with 2 gauge wire and bolt on ends purchased at an auto parts store.
I hope this proves useful to someone as it took several hours to collect my thoughts and write!
Regards,
Ben