To convert or not to convert

I am making plans to repair/restore my 1944 A. It is still on the 6V system with the mag. The rest of the electrical system is shot, with parts of wiring harness missing and no generator. What are the benefits of converting this to a 12 volt system rather than restoring it to original specs? How hard is the conversion?

Whether or not to convert to 12 volts? Answer is “it depends”.

If your tractor is going to be a daily worker then by all means convert it 12 volts and install an alternator. This uses the least expensive parts, requires the least maintenance, provides reliable starting in the coldest weather, and permits the use of 12 volt halogen lights (MUCH brighter than OEM volt lights!).

However if you are simply restoring the tractor I’d recommend buying a rebuilt 6 volt generator, a new regulator and a new wiring harness and bringing the electrical system back to original. (Keep in mind a properly maintained 6 volt system will start your tractor reliably and will give excellent service for show/parade and other occasional use.)

Your total labor for either option will be about the same.

Bottom line: There’s no “right” answer(!)

Im NOT a fan of butchered up NON Original conversions, ESPECIALLY on a smaller tractors that can start run n perfrom just fine even at cold temps, but that being said heres the plus n minus:


DISADVANTAGES:

Lowers value as far as original minded collectors are concerned or authentic tractor shows

Looks weird

May be a hassle when you try n replace with other original parts

If the ground has been reversed one has to be careful about polarity issues n jumping etc

Did I mention its NOT original n butchered lol

ADVANATGES:

Usually starts better

Usually charges better n faster n even at slower idle speeds once alternator is excited

Ignition may perform better

If it converted to neg ground more people are familiar with that when it comes to jumping etc

HOWEVER Its your tractor n your choice n no one elses business as fer as Im concerned so go with it n have a nice day

Cost is minimal,,,If you use a GM 10 SI alternator they are cheap reliable n readily available......Either a ballast resistor or a new 12 volt coil is cheap n easy if you swap out a mag to a distrtibutor and if you use a mag NO CHANGES NECESSARY

John T

Looks weird? With the hood on my Super H, you can't tell if it's 6V or 12V. Only if you hack a hole in the hood, will it look weird. Unless you consider the missing voltage regulator on the back of the electrical box as "looking weird."

Frankly, given that pretty much every vehicle on the road these days is 12V negative ground, you stand a FAR better chance of not having a jump start screwed up with a converted tractor. Most people don't "get" positive ground, let alone 6V, and will just clamp the cables on the way they think they should go, i.e. red cable on starter lug, black cable on frame.

Frankly, if the electrical system is gone and you aren't concerned about complete originality, go with 12V. On an H, the Hitachi 14231 alternator is much easier to mount than a Delco 10SI and not much more expensive. It's the one they use on Farmall Cubs.

I was in the same boat as you asking the same question. I decided to keep it original ( I had all the parts) and have recently got it working correctly. I like the fact it"s original which is strickly personal preference. The six volt works well, starts in hte cold just fine.I did buy new rubber type 6volt lights which I mounted ( I didn"t want to risk breaking originals), they throw enough light for me.

My 2 cents.

Installing an alternator on an Farmall A doesn't require any non-reversable modifications.
The greatest advantage of an alternator is reliable recharging of the battery. These tractors were designed to work all day long which allowed the generator system plenty of time to recharge the battery. If you start and restart with only short run times, the battery will not get recharged. If a battery is not kept fully charged, it will sulfate and fail. An alternator will provide for a quick recharge for short run times. An alternator can provide 30-40 amps recharge if necessary while the generator would be more in the 6-8 amp range.
I use a basic 3-wire Delco 10SI. If you go with a 1-wire, it needs to have a special low turn-on regulator due to the low RPM. With the 3-wire, the ignition switch turns on the regulator. Additionally, if I have a failure, the basic Delco 10SI is readily available at the auto parts store.
K-Mo

With a magneto and hand crank you do not need a battery, generator and no additional electral system. Disadvantage, no charging system electric start or lights. Small tractor 6 volt works fine.

Thanks for the comments everybody. This is just the kind of info I was looking for. How about converting the magneto? I've seen a lot of these tractors out there with a distributor instead. Does this have anything to do with the 6 or 12 volt system, and what are the advantages? I've heard that a magneto is a pain to work with, but I don't know the first thing about it personally. What do you think?

ADLM: You don't realize it, neither do most of your respondants, however you've asked two completaly separate questions. Number one 6 or 12 volt, and in my opinion keep it 6 volt. 6 volt will start a well tuned Farmall A anywhere in North America down to temperatures as low as -40F. It you plan to use it colder than that, first get your head examined.

The second question is the charging system, and in that case alternator wins hands down. I have 3 offset Farmalls, all alternator charging. Super A with 6 volt alternator, 130 and 140 with 12 volt alternator. Super A and 130 were done in 1992, 140 in 2004. The Super A has been absolutely trouble free, even giving me 13 years on that new 6 volt battery installed in 1992. I can also tell you, next time I need a new battery for 130 and 140 they will become 6 volt alternator charging system.

Not knowing "the first thing about it personally" is the biggest perceived drawback to a magneto, and you're not alone. They can seem pretty mysterious, but you shouldn't let that scare you off. If they do fail, you either need to get a manual specific to working on the guts of them or send them out for repair. (There are, fortunately, some good mag shops around including magman, who hangs around this board, and Mainley Mags up in northern Maine. There are others, but I know those two and don't mind recommending either of them.) At the same time, most folks aren't set up to do the work on a battery distributor that has worn to where it needs work, either.

Myself, I like and prefer mags. If a tractor has one on it when I get it, I keep it, but battery ignitions are reliable, too, and I wouldn't go out of my way to convert a working battery ignition to magneto.

I don't like to say mag vs. distributor, because the mag has a distributor, as well. The difference is where the distributor gets its spark. For the battery ignition, the voltage from the spark comes from an external can that we all call a coil (it has two coils inside it, one inside the other, and isolated from each other) that gets its power from the battery. It's basically (and in terms that are too simplistic) a motor that's made so it can't turn. One coil sets up an electro-magnetic field that builds up into the other coil (a step-up transformer). Because it's all in a little can and nothing can turn, all the energy that would normally be used to turn a motor has to go somewhere. So it builds up while the points are closed, and releases as a strong enough current to make a spark when the points are opened. The current flows through the coil wire to the center post on the cap and is distributed to the spark plugs.

On a magneto, there's a spinning magnet in the middle, that generates an electro-magnetic field that is picked up by a coil that is built into the body of the mag. Just as in the battery ignition, this field build up while the points are closed and collapses when the points are opened to release the pent-up energy. At that point it flows to the "other part" of the magneto, which is nothing more than a distributor. It travels (on IH and others) through a wire (on many other types it's done inside) to a cap where the rotor distributes the energy to the plug wires.

There are die-hards with good arguments on both sides of the fence. My own observation is that battery and charging problems are far more common than magneto failures. If you have a battery and it fails, as long as you have a hand crank handy, and a magneto, being isolated from the rest of a tractor's electrical sytem, you can get started and keep running through cold weather, dead batteries, corroded connections, bad voltage regulators . . .

To my mind, there's a lot less to go wrong with a magneto than there is with a battery ignition as far as starting and running. BOth have points condeners, rotors and caps, but there are so many fewer components in a mgantoe system that are subject to problems in generating the spark. No battery, generator . . . and fewer connections and wires.

Bottom line (and this is worth the price you're paying for it). . . either system maintained well, will serve well.

Oh, I misread. I thought he was talking about an H, not an A.

Yeah, a Delco 10SI alternator hanging off the side of an A, B, C or their Super counterparts does look a little weird. The Hitachi would look more normal especially painted black or red.

Finally, a poster points out that a magneto has a distributor same as battery ignition unit on these multi cyl engines. One other thing to consider about difference between the two is that the mag starts on a retarded spark through the impulse mechanism and as soon as that disengages you are on full adavance at all engine speeds. Most H-4 mags run at about 30 degrees advance. I personally feel the engine is better served with a properly operating advance in a battery ign unit.

Magnetos are not mysterious nor difficult to maintain. They are “mysterious” only because there are not a lot of people out there who truly understand ‘em. And if a mag is kept clean and dry it will generally require LESS frequent maintenance than a distributor.

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A big advantage of magneto is your tractor will still run without a battery, generator, etc. – the magneto is completely independent, self-contained ignition. (All you need is a good arm - or a short pull - and your tractor will go.)

However as ADLM points out in his post, magnetos have only two automatic timing settings: crank and run. A distributor OTOH has a centrifugal advance which automatically adjusts the timing in over a range of RPMs. Means that a distributor-equipped tractor may use slightly less fuel under certain speed/load conditions. Also a distributor generally can be timed so the engine can idle smoothly at lower RPM than with a mag, yet will permit the engine to develop maximum power at governed RPM.

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Were the tractor mine and it was originally equipped with a magneto, I’d leave it that way!

On my A,B,C and H tractors, they are all using 6 volt generator systems. They all start right up. As far as magneto vs batery ingition, im converting my C over to the batery ignition to free up the mag so i can use it on my A as well as to do away with the junction block. And also the magnets on the mag thats on the A are pretty weak and i have extra stuff to convert the C. Now my A and B both have mags on it, i prefer mags as they start right up due to the retard timing and my H has the batery ignition on it. To me i prefer mags but the batery ignition is still pretty good. I just cant see no reason to do away with the 6 volt on them as it turns them over easy. If it was a M with the overbore kit i could see the need to convert it to a 12 volt.

MKirsch: I have GM Delco's on my SA, 130 and 140, front on in a straight line of tractor left side, you can't see anymore of the alternator than the old generator. Side on the alternator is exactly 3" shorter and 1" deeper. With alternator painted red, it's quite hard to spot the difference 200' away. I can see a shovel handle 500' away, ask my son who left the shovel behind at other end of field.