Electrical Decision

Tue Apr 16, 2013 8:56 pm

I need help in making a decision on what direction I should go on my electrical. I have read the many post on the subject of 6v -vs- 12v and I am more confused than ever. Here is what I have. When I purchased my 1948 Cub in 2004 it was running and using a 12v battery, a 14v regulator made in Germany, a 6v Cub starter and a 6v fan pulley. Not sure how the J4 magneto was configured or does it matter? I contacted John Brillman at Brillmans to purchase a wiring harness and this is what he said, "The generator & regulator that you currently are using is not correct for a Cub tractor. The regulator is not in any location that was originally used with a Cub. Our harnesses will not match up with what you have. I recommend that you go back & put the correct parts back on your tractor." Stumped I went out to my shed to see if the 6v generator was included with all the extra parts I got when I purchased the tractor and found the 6v generator with a square box attached to the top of it. I suppose the black box is the regulator/cut out. I plan to take the 6v generator to an electrical motor repairman tomorrow and have it checked to see if it works and see how much it costs to fix if it does not. I have already had my starter and 14v generator checked and they are in good working order. My Cub was completely torn down in 2004 and I am basically down to reinstalling the electrical and I will have it up and running again. What would the forum do? 6v or 12v?

Re: Electrical Decision

Tue Apr 16, 2013 9:04 pm

A well tuned Cub will easily start with 6 volts even in extreme cold temps. However, 12 volts components are cheaper to buy. You will be getting a lot of responses and probably find the answers will be pretty evenly split between 6 & 12 volt. This is like asking what oil to use. It is just a matter of preference.

Re: Electrical Decision

Tue Apr 16, 2013 9:37 pm

I have 3 cubs with 6 volt oil :D and one with 12 volt oil :D . That's the way I got them. Have had two generators rebuilt since they didn't work when I got them. Not to expensive and I like the original look. However, the snow blade is on the 12 volt because it starts the best in the winter :o . To me this debate is about the same as do you want two quarts or a half gallon? They'll both start the Cub.

Re: Electrical Decision

Tue Apr 16, 2013 10:25 pm

Get the gernerator rebuilt and if the cut-out is shot, replace it with a good quality AC Delco regulator. See this thread - Generator and Cut-Out. A well maintained 6v system is as good or better than a 12v system. It is the maintenance that makes the difference. A 12 volt conversion is useless unless the underlying problems are corrected first, and if you have corrected the problem the conversion becomes redundant. All the connections have to be clean and bright metal, all terminals need to be clean, bright and secure, all the cabling needs to have continuity - no breaks, cracks in the insulation or breaks in the cables themselves. Good basic maintenance.

Image to what Jeff said:

Scrivet wrote:I have 3 cubs with 6 volt oil :D and one with 12 volt oil :D . That's the way I got them. Have had two generators rebuilt since they didn't work when I got them. Not to expensive and I like the original look. However, the snow blade is on the 12 volt because it starts the best in the winter :o . To me this debate is about the same as do you want two quarts or a half gallon? They'll both start the Cub.

I just don't have any 12v Cubs :lol:

Re: Electrical Decision

Tue Apr 16, 2013 11:01 pm

[quote="Rudi"] A well maintained 6v system is as good or better than a 12v system.

Do you realty believe this Rudi
Because it is just not so in my opinion. If you ever had owned a good 12 volt cub you would not make that statement I can assure you. I know the cost of converting to 12 volt and I also know the cost of a good 6 volt regulator as well as the cost of rebuilding a 6 volt generator. If you want to keep it original by all means keep it 6 volt. If you want it trouble free change it to 12 volt correctly. A poorly done conversion is more trouble that 6 volt ever was.

Re: Electrical Decision

Wed Apr 17, 2013 5:03 am

I have 3 cubs that are all still original 6 volt, magneto. Since they are magneto and well-tuned, I use the hand crank, and don't worry about the charging system. If I used them at night, I would have to keep the charging system up better. Do whatever you want.

Re: Electrical Decision

Wed Apr 17, 2013 5:58 am

Most everyone makes a good point....Especially BarnYard and Boss....Since you asked I would say 12v for work 6v of course for show...12 v does start easier in poor conditions...I have both (on working tractors)...I prefer the 12 v for convenience....And its getting harder to find a 6 v battery charger..ha ha...Dave

Re: Electrical Decision

Wed Apr 17, 2013 6:04 am

if you ever want to run an electrical accessory like a sprayer, winch, generator...you will need it to be 12 volts.


Re: Electrical Decision

Wed Apr 17, 2013 7:39 am

My criteria is simple. When the 6v generator stops working I take it to the shop. It is tested and if the repair is less than the cost of a rebuilt alternator it stays 6v. I get a 12v Delco for $35 plus the old generator. Also figured in are the lights wiring and battery. This only applies to a working tractor not a trailer queen.

Re: Electrical Decision

Wed Apr 17, 2013 8:20 am

I prefer to keep things 'original'..... BUT, I can tell you if your Cub doesn't have the original components to start with it will be outrageously expensive to make it 'original'. 6V stuff is getting harder to find every day. I have more $$ in the rebuild of my 6v generator than a 12v 'conversion' would cost. Price out the wire from the battery to starter on a 6v Cub (it's twice the size of 12v. NOTE: factory 12v starter is wired differently).

If the mag works you can (possibly?) leave the 'ignition' system alone and use 12v for starting, lighting and charging. An alternator is pretty well hidden under the hood and few people will notice, no VR so you don't even need a 'dummy' one to look original.

It's a whole lot easier to find a 12V battery that will fit in a battery box with the lid.

Your trip to the auto electric guy will give you good starting point. My guess is the generator was off for a reason and his estimate will help you make a decision.

Re: Electrical Decision

Wed Apr 17, 2013 8:21 am

I have several 6v, one 12v original and 1 12v conversion. I have found the 6v, if properly tuned, start just fine. On the other hand, 6v parts ARE expensive WHEN you can find them (ever compare the price difference in the battery cables for 6v vs 12v :shock: ) The two 12v units turn over faster and start quicker (in my experience) particularly the conversion (when you are pushing a 6v starter with 12 volts)
Just my 2 cents.

Re: Electrical Decision

Wed Apr 17, 2013 9:06 am


Actually the answer is a most definite yes. I happen to have a 12 volt 56 here and it is more trouble than it is worth. If it actually ends up being mine, it will be turned back to a 6 volt magneto equipped Cub because that is the way it originally came.

For the most part, Ellie, never fails to start when I need her unless I need to do some more maintenance. On a 65 year old tractor there is always maintenance to do and living close to the ocean there is always corrosion to deal with as there is a lot of moisture in the air and it doesn't matter if it is 6v or 12v. As I said before repairing a 6v generator, getting a good 6v regulator is no more expensive than buying an alternator as well as a new 12 volt battery and all the bulbs and upgrading the ammeter if needed. That gets expensive. Read this thread again ... - Generator and Cut-Out. I got my genny's done, a s/g and a new regulator for around $300.00 and that is cheap up here. It was also done at a qualified genuine AC Delco Service Center using Delco parts. Definite class job by class techs. And they can usually do a generator in an hour. That is cheap especially to have an original redone properly. My local shop has lots of 6v generators for Cubs which surprised the heck out of me and they are very reasonable. One just has to be imaginative and not want everything right this second. A little patience goes a long way.

So yes, I do believe that a well maintained 6v system is the equal of any 12v system. Remember - I live where temps below -50 are not uncommon. There are days when my vans won't start and they are all 12v, but Ellie will ... :!: Yes she is kept indoors and on a Battery Minder but that is only part of the story. Well maintained is the key.

Is there a place for 12v. Most definitely. Like 6v it is not the only answer. It depends on a lot of things. If your Cub was missing the genny, cutout and battery, then it would probably make a whole lot of sense to convert it over properly to a 12v system. However, if you still have all the original equipment and it just needs maintenance then it is far more economical to fix what ever the problems are with the genny and cutout/regulator as well as any other underlying problems than to convert it over to 12 volt and still have the underlying problems. Also, if your Cub came with 12 volt, then by all means leave it exactly that way - just make sure the maintenance is done.

I guess it is like Oil, Paint, Hydraulic Fluid or tire brands - it all boils down to personal preference, personal budget restraints and of course the desired outcomes - restored to original, repaired to be a working tractor or somewhere in between.

Re: Electrical Decision

Wed Apr 17, 2013 12:55 pm

The answer to your question depends on how important originality is to you, and how much work you are willing to do.

I prefer originality, but I am also frugal. In your situation, I would have the generator and cut off/regulator tested; if they work, I would put them back on the tractor. If they don't, I would stay with the alternator, and make up a harness that fits. There aren't that many wires, so it isn't that big a project.

As far as the magneto, that is self-contained and entirely separate from the rest of the wiring.

I agree with Rudy, that a well-maintained 6v system works every bit as well as a 12v. However, as TJG points out, if you want to run electrical equipment, having 12v is a plus. I have a sprayer, and have to piggy-back a boneyare 12v battery on the tongue. Sure makes it heavy to hook up, but it works.

Re: Electrical Decision

Wed Apr 17, 2013 7:57 pm

I want to thank everyone for their responses. Every response has been thought provoking. This is one decision on the rebuild that I have been waffling on. I like the idea of taking the tractor back to its original 6v configuration, but having no experience with a 6v system, I have no reason to dislike it. I also like all the positives of a 12v that have been mentioned in everyone's posts. Unfortunately, when it comes to electrical, I am a like a lost ball in tall weeds. My original intent was to go back to 12v until it was suggested that I go back original. This gave me reason to doubt my decision. If the tractor was running and using a 12v battery, does that mean that the previous owner did something to reconfigure the 6v starter that I have to 12v? Also, does it matter that the pulley the tractor was using was for a 6v system (smaller pulley toward the engine, larger pulley toward the radiator) and Is there seperate configurations for the magneto? I guess my decision will come down to cost. I took the 6v generator in this afternoon to be looked at and I am awaiting his determination.

Re: Electrical Decision

Wed Apr 17, 2013 9:05 pm

While I am not "married" to any configuration, I will echo the fact that proper tuning of the engine is key. Mine too is 6v w/ cutout. First thing I did when I bought it was go through the generator and cutout cleaning contacts and commutator and setting air gaps. I also cleaned and/or replaced ALL CONNECTIONS!!! That point cannot be stressed enough.... ALL CONNECTIONS MUST BE CLEAN/TIGHT. Higher voltage is not a replacement for good electrical maintenance. I have had no problems whatsoever. If the generator dies (which I doubt will be in my lifetime) I will take the least expensive route to repair.