[AT] tractor electrical question

Sat Aug 28 11:51:25 PDT 2021

I'm sorry I didn't get in on this sooner. This was the kind of stuff I used
to work on. Actually everything I used to work on in the early days was
just 6 volts at the battery.  :-)  A lot of it still is.
I was not following this thread and it was moving quickly.
Son Scott and I spent weeks off and on working when we could on a balky LP
powered high lift basket. It used to take a bit of starter spinning to
start, then it just wouldn't fire at all. That is not something you want on
something that pushes you 30' in the air... We knew the ignition system was
OK because it would run perfectly on a bit of starting fluid. Scott cleaned
the innards of the regulator / heat exchanger / vaporizer, but it still was
not getting fuel. I decided to get the LP tank filled (forklift type tank)
just to be sure of maximum pressure. Then it would try to start but would
not idle at all. That triggered Scott to try to change the regulator
setting and it now starts instantly. That looks pretty simple here on paper
but it was damned hot and we had little time since he works so many hours.
We also had eliminated 300 to 400 things that were not a problem...  :-)
The amount of wiring involved in this silly thing is mind blowing.
Everything is duplicated so you can control it from the basket or from the
ground by flipping a switch.
Anywho, I had looked at John's first message and realized that I was not
familiar with that tractor and went back to my other 200 projects.  :-)
I started trying to catch up on the messages a few days later.
I'm kind of fuzzy on which tractors, cars and trucks were 6 volts and which
were 12 volts these days. I think that the 12 volt ones started about 1955
or 1956? The MF-65 and the MF-165 were both 12 volts but they were both
diesel so it didn't matter. The IH 300 Utility and the Farmall 400 (both
1955 and 1956) were still 6 volts.
As I read Ken's post everything was clicking in my head. Ford used those
resister wires but Chrysler and AMC and I'm sure others used the little
ceramic bar with a coil in it. I have no idea what everybody else used back
then. It sticks in my head that Chevy used to ceramic resister but  I never
owned a 12 volt one until the new fangled ones came along so I can't be
sure.
As I recall you could buy those resistance wires from Ford and probably
parts stores. Most of my parts came from the salvage guys.  :-)    You
could buy the nichrome wire by the foot and hook it up to a battery and
start snipping it down until you were close to 6 volts... It didn't have to
be exact.
If I recall correctly, if the resistance wire failed a lot of guys would
take it off at the solenoid and hook the 12 volt "start" wire to that
terminal and drive it until they got it fixed.
I didn't actually know that the resistance wire was nichrome until about
1959 when I acquired a batch to wind into heating coils for a ceramics kiln
I was building from scratch. That came from an electrical supply company in
Indy called Shelby Electric Supply Co.
It kind of scares me a little that I remember that.  :-)  I have to wonder
what information should have been stored in that spot and got lost.  :-)

On Sat, Aug 28, 2021 at 11:40 AM Ken Knierim <ken.knierim at gmail.com> wrote:

> John,
>     Sorry I didn't get on it sooner.  I learned about that wiring issue
> from my Dad 40 years ago and actually had to teach my son about that
> ignition wiring as we're building him a '65 Rustang.
> OK, I'm learning body work and trying to make it into a Mustang. (Youtube
> Fitzee's Fabrications and get yourself a cold drink)
>
> Glad you got it figured out.
>
> Ken in AZ
>
> On Fri, Aug 27, 2021 at 8:27 PM John Hall <jtchall at nc.rr.com> wrote:
>
>> Ken, you summed this situation up perfectly, right down to the pink
>> resistor wire. Everything I researched in 2 days you put into 2
>> paragraphs, right down to what the wire is made of!
>>
>> John Hall
>>
>>
>> On 8/27/2021 9:21 PM, Ken Knierim wrote:
>> > On the 1960's Ford vehicles (and others, I'm sure) they had a wire in
>> > the harness that was specifically resistive which seems to match some
>> > of the descriptions given. If wire has 12V on one end and 6V on the
>> > other end going into the coil, it's like having the resistor inline.
>> > The vehicles had a wire from the solenoid to the coil that would
>> > bypass the resistive element in the harness by going straight to the
>> > battery for starting purposes, giving full battery voltage (albeit
>> > drawn down by the starter) to make the spark hotter (since the battery
>> > voltage would drop severely during cranking it made starting hard).
>> > The coils were set up to run on 6-8 volts to make this work. If this
>> > is the same in your tractor application it could be part of what
>> > you're seeing. These wires are generally nichrome wire and have a few
>> > ohms to them (should be enough to measure on a DVM if disconnected
>> > from the rest of the circuit; it should be similar to a resistor
>> > inline as it does the same function). Nichrome wire is pretty
>> > resilient to aging but connecting to it (with perhaps a crimp
>> > connector or something like that) could be a problem over time.
>> >    Since you're able to get the thing to work correctly with a jumper
>> > from the battery it seems there is resistance somewhere. I think you
>> > mentioned having 12V at the switch but 6V at the coil when sitting
>> > still and the points closed. That sounds like a resistive wire in the
>> > harness. My thinking would be to run a new wire from the switch,
>> > through a regular ballast resistor and to the coil to bypass the
>> > potentially bad resistive wire in the harness (it may be heating up
>> > and the connections giving you fits).
>> >
>> > Just my $0.02 but those pink Ford wires hosed a lot of folks over the
>> > years.... :)
>> >
>> > Ken in AZ
>> >
>>
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-- 
-- 

Francis Robinson
aka "farmer"
Central Indiana USA
robinson46176 at gmail.com
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