641 6 volt coil question

[Jim.ME]

A 641, heck any ford models before 1965, is not wired to supply 12 volts to a 6 volt coil while the solenoid is active.
Using the solenoid style that can be wired that way will disable the starter interlock safety feature.
Keith

It can be done by using a 5 terminal, isolated base solenoid. Standard Motor Products SS582 (Echlin ST83) is one. I believe Standard Motor Products SS590 (Echlin ST96 or ST96SB) is another that should work.

 

[Tony Jacobs]

It can be done by using a 5 terminal, isolated base solenoid. Standard Motor Products SS582 (Echlin ST83) is one. I believe Standard Motor Products SS590 (Echlin ST96 or ST96SB) is another that should work.

Yes sir Jim ST-83 works fine been using them for years . No modifications to the original Ford wiring harness , just a length of wire from the solenoid to the coil .

 

[Tony Jacobs]

That was the last official model year, but they continued to make small batches of various 4 cylinder models after that. Mostly the 4 cylinder 2000 offset model. They continued making those until the 1710 offset was release because certain customers kept demanding small offset tractors.

The Only 4 cylinder tractor that was built was the Offset . Ford documentation only shows it being built until 1969 . The Jap Scrap 1710 came out in the 80’s Ford wasn’t building any Offsets that long . Now wether there was any built Offsets sitting in some parts Depot that could have been a possibility but not one I was aware of .

 

[Tony Jacobs]

I had a 63 vw bug, 6 volt negative ground

Never worked on anything built by the Facist Five and never will never mind own one .

 

[Tony Jacobs]

Page from my veteran Neihoff electrical parts catalog.View attachment 158433

That’s interesting but as I said never saw it , never learned it . Never had a Chevy between the 1940-1954 year range because they were not in my interests . Failures like Nash , Packard and Studebaker were never interest to me either so I never payed any attention to them either .

 

[Keith Williams]

It can be done by using a 5 terminal, isolated base solenoid. Standard Motor Products SS582 (Echlin ST83) is one. I believe Standard Motor Products SS590 (Echlin ST96 or ST96SB) is another that should work.

I stand corrected.
Thank you for the detailed drawing.
Keith

 

[Tony Jacobs]

That’s interesting but as I said never saw it , never learned it . Never had a Chevy between the 1940-1954 year range because they were not in my interests . Failures like Nash , Packard and Studebaker were never interest to me either so I never payed any attention to them either .

Hello Duner , Now correct me if I wrong but from what I remember 6 volt positive ground was chosen because corrosion was a problem in the beginning years of the Automotive Industry . The old Wooden case tar sealed batteries with the exposed cell connectors on the top of the battery , the wiring and battery cables wrapped in cloth because the plastic coatings were years away from being developed . So between moisture / condensation , stray acid spills and being exposed to the elements all the time electrical systems had it pretty rough in the beginning even though they were pretty simple . Now Positve Ground was chosen because the flow of Electrons ? Through the wiring and cables was to keep the bulk of the corrosion on the ground side rather than the components themselves . (Versus today where we have to deal with corrosion on the Positive post because the flow is just the opposite) I suppose it was easier to replace those old braided ground straps and clean ground connnections rather than replacing or rebuilding components even they rebuilt everything back then versus rebuilding nothing today . Now fast forward to the early 50’s when the first overhead valve , high compression V8’s were coming out needing more cranking power . 12 volt Negative ground was chosen to be the Industry Standard because electrical systems were beginning to get more complicated . Capacitors, Diodes , Resistors , Transistors etc etc were being developed and used but all of these components liked to grounded on the Negative side . Now I’m sure companies like Nash , Studebaker and Packard thought they could change the Industry but for Packard the loss of millions through their failed attempt at changing over to 12 volt positive ground couldn’t come at a worse time because it was just another nail in the coffin for them . Now if Studebaker Big Wigs had been smart they should partnered up with Willy’s at the time and at least they probably would have survived because Studebaker did build a reliable product . Tony

 

[soaked]

Hi ole fred,
Im curious about the resistor that came in your conversion kit. Was it 0.6 ohms,
Or 3.5 ish, or more, like these

None in the pic should pair with a 1.0 - 1.2 ohm 6 volt coil, going in a 12 volt conversion, in my opinion. Too much resistance.
These are leftovers, as all got 3.0 ohm 12 volt coils.
The 3.4 ohm resistor in the pic was on a 12 volt converted, sidemount 8n, with a 6 volt 1.2 ohm coil. (4.6 total) Sometimes wouldn't start. Not enough spark. Made up a short jumper wire, and connected it to the spades to bypass when trying to start. Always fired right up. Left it on till the alternator kicked up the volts. It did run ok unclipped.

 

[ole fred]

Hi ole fred,
Im curious about the resistor that came in your conversion kit. Was it 0.6 ohms,
Or 3.5 ish, or more, like these
View attachment 158804
None in the pic should pair with a 1.0 - 1.2 ohm 6 volt coil, going in a 12 volt conversion, in my opinion. Too much resistance.
These are leftovers, as all got 3.0 ohm 12 volt coils.
The 3.4 ohm resistor in the pic was on a 12 volt converted, sidemount 8n, with a 6 volt 1.2 ohm coil. (4.6 total) Sometimes wouldn't start. Not enough spark. Made up a short jumper wire, and connected it to the spades to bypass when trying to start. Always fired right up. Left it on till the alternator kicked up the volts. It did run ok unclipped.

I didn't buy the complete kit as I have plenty of alternators lying around. I did buy two of the resistors and one coil with a resistor. As close as I can tell they measure about .8 ohm. Definitely less than one. I don't think that is enough. I'll see. My 961 has one of those resistors and it seems fine, but I've only run it maybe 25 hours or so. I think maybe I should file the points as it doesn't seem to be running and starting as good as it did. My 851 has a 3 ohm resistor - or maybe 4, I don't remember. It had trouble starting unless the battery was at full charge. I discussed that here a year ago or so. Now, I do as you said you do - put jumper wire across the resistor just to get it started, then take if off.

 

[Tony Jacobs]

Hi ole fred,
Im curious about the resistor that came in your conversion kit. Was it 0.6 ohms,
Or 3.5 ish, or more, like these
View attachment 158804
None in the pic should pair with a 1.0 - 1.2 ohm 6 volt coil, going in a 12 volt conversion, in my opinion. Too much resistance.
These are leftovers, as all got 3.0 ohm 12 volt coils.
The 3.4 ohm resistor in the pic was on a 12 volt converted, sidemount 8n, with a 6 volt 1.2 ohm coil. (4.6 total) Sometimes wouldn't start. Not enough spark. Made up a short jumper wire, and connected it to the spades to bypass when trying to start. Always fired right up. Left it on till the alternator kicked up the volts. It did run ok unclipped.

Soaked , 12 volt conversion kits do not come with 6 volt coils . 6 volt coils do not use or require a resistor at all and 6 volt coils do not work on 12 volt conversions . Then you say as all got 3.0 ohm 12 volt coils , What did ? . They should have had them in the first place . Then you talk about an 8N using a short jumper wire on it to start it , why ? just put a 12 volt coil on and fix the problem ? Nothing makes any sense . Sounds like the original posters work ! Pretty soon according to his last post he will now have three tractors that don’t start or run correctly !

 

[Tony Jacobs]

To be clear. They supplied a 6-volt coil labeled to use with an external resistor, as the 12-volt coil. The picture of the coil below would be the aftermarket replacement for those coils. Yes, if the resistor bypass wiring was hooked up the coil received battery voltage while the starter was engaged to crank the engine.

ole fred could do this with his old 6-volt coil, as long as he has a resistor ahead of the coil and has a solenoid (relay) with the ignition bypass terminal.

View attachment 158487

Hello Jim , I was going to post to you before about this . IC-12 is a 12 volt only coil according to Napa . Matter of fact it is a Delco speced coil . The internal resistance and the external resistor needed for the 12 volt use is also Delco specs . It is also larger diameter requiring a bigger mounting bracket . IC-10 is actually a Ford spec coil and a better choice for 12 volt and even fits the factory Ford mounting bracket . IC-8 is a Ford speced 6volt only coil .

 

[soaked]

Soaked , 12 volt conversion kits do not come with 6 volt coils . 6 volt coils do not use or require a resistor at all and 6 volt coils do not work on 12 volt conversions . Then you say as all got 3.0 ohm 12 volt coils , What did ? . They should have had them in the first place . Then you talk about an 8N using a short jumper wire on it to start it , why ? just put a 12 volt coil on and fix the problem ? Nothing makes any sense . Sounds like the original posters work ! Pretty soon according to his last post he will now have three tractors that don’t start or run correctly !

Hi Tony,
Ive bought many non running 8n sidemounts. Some already converted to 12, and some still 6 volt.
Of course the 8n sidemount came as a 6 volter without a resistor.
Kits available to convert to 12 come with resistors should someone want to run their old 6 volt coil. I never have. Thats why all the leftovers. The resistors in my pic came in 12 volt kits for 8n sidemounts, or were installed when I got em.
I only put 12 volt 3.0 ohm coils in. Some napa, or pertronix, or the one sold here.
The 8n with the conversion to 12, that came to me with 1.2 ohm 6 volt coil and big 3.4 ohm resistor, was fun playing with it, and points. Now its running with pertronix 1244A, and 3.0 ohm coil.
Here are coils that came off some 8ns.
All are 6, except there is a 1.6 ohm 12 volt coil in the pic.

John

 

[docmirror]

6V to 12V conversion history. Blame it on - air conditioning. GM offered auto AC on a few lux brands like Caddie and Buick Roadmaster. The AC systems came with a bunch of motors and solenoids and in a way to save wiring sizes, GM switched in 53 to 12V just for - AC. Why they chose to switch ground planes, I have never figure out, except what I've found third hand is that batteries for aircraft were light weight 12V neg ground already, and Johnson could make a 12V battery neg ground for cheaper than pos ground. May be BS, I don't know.

The DR-156 reg pictured sort of confirms this as it works for all those cars with AC AND, for cars like the Chevy which were later converted from 6V negative which was common as the early Chevy with V8 were getting harder to start with the 6V batts. Delco-Remy(DR) was the OEM offering for all GM products through the 60s. There was that 1953-56 period when only the AC cars had 12V neg ground, until adoption by most/all GM cars in 56-57-ish timeframe.

Packard had a 12V system way back, I don't know when but Stude was still using 6V and when they merged, in another idiotic decision, it was Packard that switch to 6, rather than Stude switching over to 12. DOH!

As for the Ford tractor switchover, the 12V coil will start easily with the 6V starter spinning a lot faster, developing more adiabatic heat/pressure. The stress on the 12V coil during cranking will lower the voltage a bit.

 

[Tony Jacobs]

Hi Tony,
Ive bought many non running 8n sidemounts. Some already converted to 12, and some still 6 volt.
Of course the 8n sidemount came as a 6 volter without a resistor.
Kits available to convert to 12 come with resistors should someone want to run their old 6 volt coil. I never have. Thats why all the leftovers. The resistors in my pic came in 12 volt kits for 8n sidemounts, or were installed when I got em.
I only put 12 volt 3.0 ohm coils in. Some napa, or pertronix, or the one sold here.
The 8n with the conversion to 12, that came to me with 1.2 ohm 6 volt coil and big 3.4 ohm resistor, was fun playing with it, and points. Now its running with pertronix 1244A, and 3.0 ohm coil.
Here are coils that came off some 8ns.
All are 6, except there is a 1.6 ohm 12 volt coil in the pic.
View attachment 159095
John

Hello John , Other than myself I never met anyone who knows little restoration details like the dimpled coil so knowing that I assumed you knew more than you were saying but I as I said it just didn’t make any sense . The resistor in the kits are for the 12 volt coil in the kits . I was a Tisco Dealer for a long time and there was never a kit that even suggested using a 6 volt coil let alone installing a resistor on one . A 12 volt coil still needs a resistor unless it is internally resisted . I don’t understand why anyone doing a 12 volt conversion would be using any 6 volt parts to begin with . If they were the same Ford wouldn’t have made both 6 volt and 12 volt parts to begin with it pretty simple .

 

[soaked]

Hello John , Other than myself I never met anyone who knows little restoration details like the dimpled coil so knowing that I assumed you knew more than you were saying but I as I said it just didn’t make any sense . The resistor in the kits are for the 12 volt coil in the kits . I was a Tisco Dealer for a long time and there was never a kit that even suggested using a 6 volt coil let alone installing a resistor on one . A 12 volt coil still needs a resistor unless it is internally resisted . I don’t understand why anyone doing a 12 volt conversion would be using any 6 volt parts to begin with . If they were the same Ford wouldn’t have made both 6 volt and 12 volt parts to begin with it pretty simple .

Resistors in kits are also for 6 volt coils

 

[Tony Jacobs]

Resistors in kits are also for 6 volt coils
View attachment 159106

Never saw one of those kits , Who makes it ? That’s the dumbest thing I ever heard of ! When you install a 12 volt coil on a 12 volt conversion whether it is externally resisted or internally resisted you are NOT cutting it down to 6 volts with 3.0 / 3.5 ohms resistance . It’s not going to start very good with only 6 volts during cranking just like a 6 volt tractor so putting a resistor on it and cutting down more is ridiculous

 

[soaked]

I hoped you might recognize a listing from here at YT.
My aim posting to ole fred was to inform that kit resistors may not be very helpful, if using a 6 volt coil.
But as he bought two .8 resistors, figured he would line em up for .8 + .8 = 1.6 ohms, and thats not too far from 3.0 ohms, if his 8ba12029 has original specs.
I still dont understand what a .6 ohm resistor is doing in a 12 volt conversion kit...

Respectfully
John

 

[Tony Jacobs]

I hoped you might recognize a listing from here at YT.
My aim posting to ole fred was to inform that kit resistors may not be very helpful, if using a 6 volt coil.
But as he bought two .8 resistors, figured he would line em up for .8 + .8 = 1.6 ohms, and thats not too far from 3.0 ohms, if his 8ba12029 has original specs.
I still dont understand what a .6 ohm resistor is doing in a 12 volt conversion kit...
View attachment 159110
Respectfully
John

Well as I said I was a Tisco Dealer so I had no reason to buy where I wasn’t a Dealer . Plus I hate chinese garbage and garbage from india and turkey . So I rebuild everything including clutches and brake shoes . I make a lot of parts for jobs also not to mention hunting down good quality parts from anywhere I can find them . Your aim should be posting NOT to use 6 volt parts on a 12 volt system because it will NEVER work correctly . If 6 volt and 12 volt were compatible there would be no need to have both since they are not compatible we have both . I don’t understand where this Foolish thinking comes from . Tisco never advertised anything as stupid as that and I have never heard of stupid problems like this until recent years . Just like until these recent years I have heard of countless idiots draining batteries dead to charge them in reverse polarity and then wonder why they explode ! The amount of stupidity is reaching epidemic levels ! As far as ole Fred goes he got two tractors that he has done these half fast incorrect hacks on that don’t start and or run correctly as he said in his own words yet he’s doing it again so that will be three with more problems then when he started ! You would think that he would realize 6 volts parts don’t work with 12 volts . Unless of course he using the Edison approach where he has to do 997 more to hit 1000 ways not to convert a tractor to 12 volts if you want it to start and run correctly .

 

[Sean in PA]

6 volt coils do not use or require a resistor at all and 6 volt coils do not work on 12 volt conversions . T

A 6 volt coil works just fine in a 12 volt conversion when you use an external resistor. Why do you think that most automotive and tractor manufacturers used external resistors when they first switched to 12 volt systems? Because they continued to use coils that were originally designed for 6 volts.

 

[soaked]

Unless im off my rocker kissing Betty Crocker,, resistors for 6 to12 should be a value that when added with the coil ohms should be 3.0 ohms, or very close. So a 1.2 ohm 6 volt coil should pair with a 1.8 ohm resistor.