OK to briefly run a tractor on 12V with a 6V coil?

atlarge54 · May 14, 2010

Looking at an Allis B tomorrow and I'm assuming it's a 6V and I don't have any 6V batteries. Can I run for a short time on 12V, just to check it out and maybe drive on trailer?

MNGB · May 14, 2010

Hi yes that would be ok just don't try the lights.
GB in MN

schriffs · May 14, 2010

The short answer is yes. Short term, the coil should be ok, however the charging system might be a problem if it is hooked up.

teddy52food · May 14, 2010

If you have another coil, you can wire it in & add some resistance to save the points.

Brad Gyde · May 14, 2010

I'm sure someone will argue this, as I myself argue it.. BUT.. A very good friend of mine had a grandfather that worked in a factory that made coils, and he claims to this day that his grandfather always said there was NO DIFFERENCE in 6v and 12v coils.. I find it hard to believe, but I didn't work in the factory, his grandad did.. and he's been gone for many years now.

On another note.. I had a coil go out in my combine a few years back on a Saturday afternoon.. I ran to the shop, grabbed the first used coil I could find, which was a 6v.. I ran it 2 days that way and finished up combining. The coil was still on it when I sold it, but I did send the new owner down the road with a brand new coil in his hand.

My suggestion.. do what you have to do. The worst might happen is you'll cook the coil/points. I dare to bet the old tractor has been subject to worse in it's life.

Brad

JMS/.MN · May 14, 2010

Up until the early 50s, the B tractors had a magneto, so it didn"t use a battery ignition coil. Starter will be fine with 12 volts.

old · May 14, 2010

If it does in fact have a distributor instead of a mag sure you can done it time and time again and even have one or 2 tractors still that I run on 12 volts and they still have the 6 volt coils and no ballast resister on them. Is it good for the coil no but most round can cols will hold up well for a long time unless you leave the switch on and not have them running if you do that then you can end up with a big big mess. Ask me if you want to rest of the story. So short answer is go for it but do not let it sit non-running with the sitch on for more then 2 minutes

Jerry/MT · May 14, 2010

If you only run it for a short time you be fine. You"ll have about twice the normal current going through it if you run it without a resistor and it will overheat if you run it for too long. keep it under 15-10 minutes and you most likely won"t fry it.

big jt · May 15, 2010

I know this bucks what the rest have said but I will relay my personal exp. I have two WD45 allis's that are still running the 6V coil on 12. Been running both of them that way for over 20 years. No ballast resistor and haven't had to replace the coil, condenser in that time either.

Once again I know this goes against what is common thought but this is what I have experienced. Actually the times I have worked with them the resistors were usually the issue when I ran into ignition problems.

SCHMUCK 1 · May 15, 2010

As others have said, a short while should be fine as far as the coil goes. I had a bad set of plugs in my WD-45 a while back and used a piece of wire to short out the ballast resistor to start it a couple of times, after it was running, I removed the wire until I got new plugs. However, I'm not so sure what a 12V battery will do to a regulator /generator. Maybe nothing, but to be sure, you might want to dis-connect them until you get a 6V battery.

gene bender · May 15, 2010

Better disconnect the charging system coil is not the problem but the gen and reg is.

John T · May 15, 2010

If its only for a short while, YES you can get by running 12 volts on a 6 volt coil assuming it even has a coil distributor ignition versus a Magneto which doesnt use battery power and makes no difference. Dont turn on any lights it would pop them.

You didnt ask about the charging system, but polarity issues could cause a problem, you may wanna disconnect the chagring system to be safe.

John T

OK to briefly run a tractor on 12V with a 6V coil?

atlarge54

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MNGB

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schriffs

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teddy52food

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Brad Gyde

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JMS/.MN

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old

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Jerry/MT

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