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6 volt vs 12 volt on an H

J

Joe in CA

Member
I can't decide on whether it would be better to keep a 6 volt system on an H or convert it to a 12 volt.

The existing 6 volt system needs a magneto, so it's a good time to switch it, if it's ever going to get done.

What are some thoughts on this? Is the 12 volt system enough better to justify taking the machine off origional?
 
Joe, I have a 51' H and considered the same idea. I prefer originality over modern convienience, based on the fact my tractor will never be on the road and require flasing signals. I bought a new regulator and gauge, had my generator serviced. I rewired it using the correct wiring diagram and had great results. My tractor starts as quickly as any 12 volt converted tractor.You must use 1 or 2 gauge battery cables to get the proper amperage flowing from a 6 volt battery, and make sure all contact points are clean. A company called Steiner also has 6 volt light bulbs that are as bright as 12 volt bulbs. Make sure you purchase headlight bulbs and not just 6 volt bulbs. The best part for me was based on my preference to originality , I did not have any fabrication work and never even considered cutting the hood like many will do. You can find a used distributor assembly for a fair price through other sources, but a properly working magneto or one that is built to be "hotter" will work great on your tractor. Good Luck, Mike
 
Start with the starter get it refreshed so its up to par then do the same with the generator now with new 1ga cables and the correct size battery to fit in the battery box you will be good to go. You can find good mags all the time.
 
The magneto is not affected by the rest of the electrical system, so it is not significant either way. My H has a mag and is on 12 volt with an alternator and it was when I got it, the main benefit I see is that I can use aftermarket lights and that the batteries are cheaper.
Zach
 
I don't have an H, so I'm not sure - but I THOUGHT that on the H you had to cut some sheet metal to fit an alternator.

Definitely something you should factor into your decision.

I'm sure others here could clarify.
 
Magneto vs. distributor has nothing to do with 6V vs. 12V.

A magneto needs no electricity either way, it makes its own.

The only difference for the distributor is you need a 12V coil, or a ballast resistor.

IMHO, whether to convert depends on the condition of the current charging system and your level of frustration. If it's currently working, leave it alone.

Stuffing an alternator under the hood is a little tricky, don't let anyone tell you otherwise. If it were easy you wouldn't see so many botched installs with missing/bent/cut hoods.
 
Me personally, I would leave it 6 volt. I've had several H's & M's over the years and never a problem with 6 volt. In fact I had a Super M with fresh overhaul that started fine in below 0 weather. Main thing is to have proper wiring and keep maintained and you will be fine. They were designed to work on 6 volt and they did and still do.
 
12 volt is not needed on an H, is borderline on an M. 12 volt just covers up dirty cables, etc, that need to be kept clean anyway. I am restoring a Super M, that has the original 6 volt on it, it starts fine, I am undecided whether to switch to 12 volt, as I already have a new unused alternator. The only advantage is that alternators need less maintenance, but that is not really a good reason to switch to 12 volt.
 
I have a delco 10SI on my H and the hood is not cut. The bracket is flipped down and it is a close fit. There is a Hitachi alternator that folks use but I had the 10SI and rebuilt it to save money, with the advice of folks on this forum.
Zach
 
I agree PERSONAL PREFERENCE your tractor your money your call. That being said, unlike an M at 6 volts where cold weather starts can be problematic, an H with a good heavy high CCA rated battery,,,,,,,,,00 Gauge Battery and Starter and Ground cables,,,,,,,,,,,,engine kept well tuned,,,,,,,,,,,,good starter motor,,,,, OUGHT TO START AND PERFORM FINE PLUS THAT WAY SHES ORIGINAL (if that matters yo you)

Yeah 12 volts and alternators are better if thats all that matters, so balance that with originality then make the call. Like Fox News, we report now you decide

John T
 
no cutting nessesary
a69727.jpg
 
My SH started fine/no problems even in the coldest weather.However,I converted to 12 v because I needed to run some 12v 'equipment' with it.
 
I have a couple of each, 6 volt and 12 volt. The Delco alt. will fit with out hood mods,mine does. The 6 is okay unless its very cold or if she does not start right up for some reason,then I run out of cranking time and speed too quickly. My everyday working tractors are 12 volts,way nicer for starting, very reliable. IMO 12 volt is the way to go, unless originality is a priority.
 
So what your saying is the mag is bad so you then want to switch to 12 volts because you need to repair the mag. Well that sort of makes no sense because a mag has nothing to do with the battery on your tractor since if is a self contained ignition system and works independent of the battery system. So are you saying your going to also switch to a battery ignition system or stay with the mag??? Sorry just trying to figure out what your really trying to say here
 
I have both. But then I repair all my own alternators, generators, and starters. To say that a M with high comp pistons will never have a problem turning over with a 6 volt battery is far fetched. I don't care if you run cables as large as your arm, the terminals inside the starter are never going to grow in size. Voltage drop is voltage drop, no matter where it occurs. It is the hot start that normally gets you in trouble. Fortunately, they normally only have to turn about one revolution to fire up. We at IH dealerships fought those hard hot starts for years until IH finally put the 450 gas on 12 volts in midproduction. Problem solved.......... I much prefer to also change the starter field windings to 12 volt but now days fields of any quality are really difficult to come up with. The ones the rebuilders use are normally sub par. When tractors are out there being used every day, things are not always perfectly up to snuff. In those cases, the 12 volt system will get you going more times than the six volt will. And, you can jump start it off most any other tractor or vis versa. I kept one H original just because I wanted to. It starts fine, but it doesn't have to do anything either.
 
I just finished up converting my last tractor to 12 volt. Never had a hot start problem but did have -30, no wind chill start problems!


I'm kinda with the other guys on this. If the Mag is the problem you can convert to 24 volt and it isn't going to fix the Mag. It's just like a rope start lawn mower. A mag produces it's own electricity to make spark. When you turn the engine off you are grounding the system out. On a push lawn mower the throttle on the engine contacts a wile and ground is. On a garden tractor with a mag ignition the key switch ground out when turned off and on old tractors like the H the push/pull switch grounds it. Really old system had a spring steel contact mounted on the mag or on one lung engines by the spark plug that you pushed to a contact or the plug to kill it.

Try trouble shooting the system. ID what is wrong and fix that. Throwing parts at something can get real expensive real fast.

You can find many post on here about converting and everyone is for or against it. If you have low compression a conversion may make it start better but you still have low compression. Don't use a conversion as a band aid to cover up another problem.

Rick
 
There is a reason you don't see 6 volt systems on any equipment in the last 40+ years. It's obsolete technology!

The biggest problem I had with 6v systems was the lack of quality of a new 6v battery. I could get the generator, wiring, starter, etc. all perfect but the batteries didn't seem to last very long. I have a couple tractors that are only used once a year to put the garden in and the 6v batteries would be dead. 12v volt batteries will last for over a year and still fire them right up.

I have 12v batteries that are 10+ years old. I never had a 6v battery last over 2-3. Some wouldn't last a year.

As batteries failed I converted every thing to 12v. I used the Delco alternator when I have plenty of room and the Hitachi when space is tight.
 
I would just fix the mag. leave it 6V, may depend on what part of the country your in, but I have two Cubs, Allis C, Case S, Farmall 100, Farmall SC, Cockshutt 20 and MM GTB all 6V and they start just fine.
 
(quoted from post at 03:54:48 05/02/12) The magneto is not affected by the rest of the electrical system, so it is not significant either way. My H has a mag and is on 12 volt with an alternator and it was when I got it, the main benefit I see is that I can use aftermarket lights and that the batteries are cheaper.
Zach
Click to expand...

Not to mention ease of use with battery chargers or jumping batteries.
 
I would leave it 6 volt. The mag is not designed to work with a faster turning 12 volt set up. My old timer mag guy told me he has seen a lot of impulses that have broke from spinning to fast. get a good hot mag and 6 will be fine.
 
With a failure rate like that, I would guess you are not taking care of them. Keep them charged up good. I get 6 to 8 years on mine.
 
If you use it to work with, convert it, if it is show leave it. I would replace the mag with a distributor if you convert it. The engine might crank fast enough to stop the impulse on the mag. I have the Hitachi alternator on my H.
 
If you stay with 6 volt,buy a group 2 battery instead of a group 1. All the old ford cars and trucks with flathead V 8 engines called for a group 2. I have have been using them in my old fords for years with good results. Not that much bigger in size but they have a lot more cranking power.
 
I maintained them just like the 12v batteries. I keep/kept low amp trickle chargers/maintainers on them. Checked and added distilled water as needed.

Bottom line is the 6v batteries just don't last as long as the 12v maintenance free.

I'm just outside Houston TX so suspect our high temps are hard on batteries. I don't remember having problems with 6v batteries growing up in IA. I really believe that the quality these days is lower than 30+ years ago.
 
I agree about how long they last. I have some 12 volt batteries that are around 10 years old and still do the job. I have never gotten more than about 3 years outta a 6 volter.
 
Have two H's, both workers, both converted to 12 volt w/ one wire alternators. (smaller Hitachi's) Both on Magnetos. One is standard bore, new pistons and sleeves and is in top shape. The other has firecrater pistons and is also in top shape, averaging 145lbs per cylinder. Both start great, and have had NO problems with batteries or magnetos plus I have much brighter lighting now.

On the magnetos "turning too fast" with a 12v starter, it was explained to me that the impulse performs two functions.
1st, and foremost as far as safety is concerned, it retards the spark to avoid engine kickback at low (handcranking) speeds.
2nd, it spins the armature over more quickly to ensure a "hot" spark at low cranking speeds.

Once the engine has reached an rpm over 200-250, the magneto is producing adequate spark w/o the impulse's assistance, so the impulse is disengaged by the centrifugal effect of the pawl design.

That being the case, IMHO, if the starter is spinning the engine over fast enough to disengage the pawls, there is no issue, as its making enough spark and there is enough flywheel inertia to carry the pistons over tdc and not "kickback"
.
If it is not spinning it fast enough to disengage the pawls, (so you're hearing the click click click of the impulse tripping) and it still isn't starting, you have other issues to address.
If it starts quickly, and the impulse only clicks a couple of times, I doubt much more wear will occur than starting it on a 6v system that trips it several times before starting.

again, just my opinion. No warrantees implied or expressed.
 
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