Farmall H 6 to 12v conversion

Anonymous-0 · Sep 8, 2013

I've searched the archives and found a lot of helpful information to make the swap as easy as it can be. The issue I'm having is I put on a brand new 12v no external resistor needed coil but it will not fire. I tried a couple old 12v coils marked use with external resistor and it will idle but not rev without missing.
When I put the original 6 volt coil on it fires right up and idles well. In neutral it will rev but under load it starts to miss. Do I need to adjust the points or plug gap for swapping to 12v? I'm taking back the new 12v coil in the morning to get another and see if it will fire.
The plugs/wires/points are old but ran fine with 6 volt system.
Thanks for any input!

Bob Kerr · Sep 8, 2013

I keep all of my 6 volt equipment 6 volt. It is what it was designed to run with and if all the connections are clean and battery cables are the correct heavy gauge, I have had no problems at all. I have 8 cars trucks and tractors with 6 volt systems.

rustred · Sep 8, 2013

i 2nd that, i keep all mine 6 volt also. i have no reason to stick a 12v batt. in my 6 volt systems everything starts as it did when new. why would i damage my starter bendix and ringgears with 12 volt.,as it engages hard. i know 12 volt spins the heck out of the engine but makes no sense to me.
and some of the hack jobs i have seen just make me enjoy my 6 volt starters even more. point and plug gap from 6-12 volt is the same.

gene bender · Sep 8, 2013

How much play in the dist shaft 12v dont solve your problem should have just stayed with 6 and got your system fixed so it was in top shape. Why would they take a coil back they sell new parts not used ones.

Anonymous-0 · Sep 8, 2013

The main reason I swapped this one is it's the only 6 volt tractor I have. For the 6 or so times I use it a year it isn't worth buying a 6 volt charger or a new battery every year. When the generator died that was the nail in the coffin.
The tractor isn't a beauty queen, it's had a hard life before I got it. Trans noise etc. As far as cost most of the parts I already had saved from a Super C that was converted but had major damage when the front bolster broke. So all it's cost me is a key switch rather than using a diode to control backfeed from the alt and a 12v coil...

Anonymous-0 · Sep 8, 2013

I will have to check shaft play.
I didn't do the swap to fix a miss, please see my other reply.
I would hope they would warrant a brand new coil that was purchased less than 5 days ago seeing that it has a warranty and must be defective? The other 12v coils I tried were used that I had laying around, I don't even remember if they were still any good (atleast 20+ yrs old)

Hayfarmer · Sep 8, 2013

When you changed to 12 volt, did you change to negative ground? If so did you change polarity on coil? I have converted 2 tractors from 6 to 12 volts and had no problem at all. I like the 12 volts as I use the tractors at night and lights are easier to find in 12 than 6 volt and alternator keeps up better when running equipment that also has lights. You could have a points or condenser problem, sounds like it misses no matter what coil you use. On one of my conversions I used a resister ahead of the 6 volt coil for a long time and it worked fine, but resisters tend to burn out.

Anonymous-0 · Sep 8, 2013

Yes, I swapped the coil to negative ground during the conversion. What really baffled me was no start off the brand new 12v coil (DOA always a possibility but...) I will get some tune up parts to remove the possibilities.
Thanks!

randy hall · Sep 8, 2013

what you should do is get an electronic ignition kit. four things you will learn on this site, six volts is better than twelve, a magneto is better than a distributor, an oil bath air cleaner is better than a paper element dry type and if it"s bigger than a cub you better have a semi to haul it.

Janicholson · Sep 8, 2013

A key switch works if you hook the alt #1 terminal to the ACC position on the switch. This puts separate voltage to the Alt when running and shuts off the connection when the key is off. (no connection to coil between the Acc and the Ign terminal on the Switch). The gap is .020" on the points. Use a meter on the coil input to assure 12v is present. 12v coils from cars usually need a resistor! Few are made as full 12v coils. So your substitute coils may Be equal to 6v coils. The coil should draw less than 4 amps when on and the engine stopped points closed. Jim

Bob · Sep 9, 2013

On the contrary, it's best to iron out any problems and get the tractor running well on the original ignition system BEFORE making the swap to EI, to eliminate entering a whole lot of possible NEW problems from entering into the mix of why it's not running well.

David G · Sep 9, 2013

I think you have a different issue going on, and I would NOT change over unless it works correctly on points.

BTW, 12V is the way to go.

merlynr · Sep 10, 2013

(quoted from post at 17:44:20 09/09/13) I think you have a different issue going on, and I would NOT change over unless it works correctly on points.

BTW, 12V is the way to go.

I converted mine a couple of years ago and wished I had done it a long time ago. It'll start right up on coldest day of winter plus I got rid of that worn out mechanical regulator.

oldtanker · Sep 10, 2013

OK, Bob and Rusted both say to leave it 6 volt cause that's the way it was designed. So does that mean on an H or an M you should never, ever add live hydraulics, power steering or a3 point cause they were not designed that way? The guy ask a question about how his tractor was running now that the conversion is done.

12 volt to me is the way to go. I have 3 tractors that have been converted to 12 volt and I'm very happy with those conversions. All will start in MN winters at -15 or colder. 1st step in a conversion is to make sure the tractor runs as it should in 6 volt. That doesn't mean the charging system has to work but the battery has to be fully charged. If it isn't running right fix that problem first. You do not want the 12 conversion to be a Band-Aid. Sounds like you got a bad coil. It happens. As you were told check for shaft play on the distributor. Check point gap too. If the points are not clean and brite put in new points. Get good ones. The ones sold by TSC and other farm supply places may be of low quality. Same with the coil. Standard, Blue Streak and NAPA all see decent points and coils.

Rick

Anonymous-0 · Sep 11, 2013

Why is it that ever time someone has a question about 12volt we hear about leaving it 6volt. They have already decided to convert or have converted. If it was such a great system why is it not still around. I converted all my tractors to 12 with out cutting them one bit and without seeing the alternator you would never know. I have never ever had a starter go bad on a 12v conversion and I think its the way to go.

Farmall H 6 to 12v conversion

Anonymous-0

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Bob Kerr

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rustred

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gene bender

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Anonymous-0

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Anonymous-0

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Hayfarmer

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Anonymous-0

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randy hall

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Janicholson

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Bob

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merlynr

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Anonymous-0

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