Farmall Cub

Why change one over to 12 from 6? Why leave one 6 and not go to 12?

This is destined to become a long thread.

Don McCombs wrote:This is destined to become a long thread.

I have the time

I changed two working tractors from 6 to 12 volt. Reason Delco 10SI alternator was considerably less than repairing the existing 6 volt generator and replacing the regulator. I haven't had a failure of the Delco 10SI on a tractor yet. I have had them fail on cars. My cost is around $40- for a rebuilt 10SI and core exchange. Includes a 1 year warranty.

12V is more modern, the alternators produce more current for brighter more powerful headlamps/taillamps or other 12V accessory. 12V stuff is also rather common, and the batteries tend to be available in newer types with longer life. The power of an electrical item is measured in watts. Watts are Volts X Amps. To get say 100 Watts, on a 12 V system i s 8.3 Amps. To get the same 100 watts on a 6V system is 16.7 Amps. Amps is a unit of current or you could call it flow. Picture a hose, one the size of a garden hose, and the other the size of a straw. You can drain water through the garden hose easier than the drinking straw. Same goes for electricity. To get 100 watts on a 6V system you need to have more flow. Hence larger wires. 6V systems are therefore slaves to restrictive wires, corrosion etc. destroy the flow and then the number of watts you can use drops off.

Now you can definately deal in 6V, I like it well. But you have to make sure your wires are good and corrosion free, and that all connections are clean and tight, and it helps to put some anti-corrosion grease over them to prevent oxidation and loss of current.

Many people will choose to convert to 12 volt when:
Having electrical problems,
Having a dead or dying generator,
Having a dead 6V battery and perhaps other issues as well.

The idea being that your costs are some what covered anyhow by saving money over the 6V components.

Why not to go 12V? Originality, 6V has worked fine on many tractors for a huge number of years, and can be made to work with no teething issues regarding burnt points or what resistor to add to the coil, or if your starter will do alright with 12V's etc. You can solve many 6V problems by cleaning the grounds, getting them nice and tight, and applying some anticorrosion grease over them to keep oxygen out. As well as fitting larger wire/battery cables as you see fit.

OKAY!!!--Ya all know what I am going to say!!!!-----12-VOLTS ALL THE WAY!!!---I know it's not original but that 6-volt stuff just don't work after 60+ years,(neither do I but when ole spine gives out, your done) same goes for 6-volts,--as said the cost to repair it is one thing and the hassel of keeping it working just don't cut it!
It is mostly owner's choice of which way they want or can afford to go!
I am not trying to PO anybody here because you all have been great guys to me!!--6-volt is the way to go on a show tractor, (because it would be original and not worked so problems would be less) posted with respect to all----sonny

Great answer PBG! Two parts are especially useful and well explained, why 12V has smaller wires (Ohms Law) and why connections are more of a problem on 6 V systems. I would be willing to bet the connections are more often a problem than people realize, critically important.

I have a preference for later Cubs, partially because they are 12V. A few years ago I would have defended keeping a 6 V system original, but it would be a whole lot cheaper and trouble free to throw an alternator and pertronics pointless ignition on a worker. Lots easier to find a 12v battery that will fit in the battery box too. A good friend of mine put an alternator on their M and couldn't be happier. The last generator rebuild I had done was $70.

You know, I'm on the other side of the fence.

I can see converting a car that you would plan to drive 100's of miles at a time. Because you get better headlight brightness, and you can have a good modern radio etc. That makes sense to me.

But on an old cub I have seriously found the 6V system to be painless. There's really not many things that can go wrong, its pretty easy to sort them out and trouble shoot. And if its not cranking fast there are 4 connections. 1, starter terminal (negative), 2 Battery terminal (negative) 3, Battery Terminal (+ ground) 4, Ground Lug (+ ground) Those 4 terminals are really the only important ones for the tractor to crank well. You can replace the negative one with a good heavy gauge wire, and crimp/solder the ends so they are nice and conductive, little fine sand paper to get nice fresh metal, bolt them down tight, spread a little vasoline or terminal grease over them. Good to go.

If you aren't charging effectively and those connections are good then its time to look at the wires to and from the generator and the dash, same if the lights aren't bright.

But really, I don't use my cub much at night anyhow, if I do its mostly for something trivial like running down to the mailbox. = Don't need much light output. And if I store my tractor very long the positive terminal comes off.