Why upgrade a 6v system to 12v

Parag0d

New User
I have been thinking about this for a
while now, but I am wondering what
exactly are the advantages of a 12v
system over a 6v system? Is it worth the
trouble to upgrade?

Thanks in advance from someone who is
learning new mechanical skills every day,
thanks to his old tractor.
 
Pluses:

1. 6 volt starter will turn faster with 12 volts.

2. Using original 6 volt coil with external ballast resistor will allow a bypass circuit to provide full 12 volts to coil for hotter spark during starting.

3. Compatibility with other modern tractors, cars and trucks for ease of jump starting.

4. Compatibility with modern 12 volt chargers and jump boxes.
 
Now days it comes down to cost plain and simple. I can buy 2 or 3 12 volt batteries for the cost of 1 6 volt one plus finding some one who can fix a 6 volt generator is not easy and the cost again it twice to 3 time the cost of using and alternator
 
(quoted from post at 23:01:19 11/10/22) I have been thinking about this for a
while now, but I am wondering what
exactly are the advantages of a 12v
system over a 6v system? Is it worth the
trouble to upgrade?

Thanks in advance from someone who is
learning new mechanical skills every day,
thanks to his old tractor.
on't call it an 'upgrade', but just an alternative, even though it may be a cost effective alternative.
 
I have 8 tractors & only 1 is still 6 volts. (Nobody will talk me into converting my Jube!!!) The nearest place that repairs generators is 100 miles away, & we have all heard the horror stories lately about finding a "good" new VR!
 
Aside from temporarily helping to cover up other starting issues, the biggest advantage is the ease of connecting modern 12V accessories.

There are disadvantages as well.

If it ain't broke, don't fix it.
 
(quoted from post at 10:48:22 11/11/22) Aside from temporarily helping to cover up other starting issues, the biggest advantage is the ease of connecting modern 12V accessories.

There are disadvantages as well.

If it ain't broke, don't fix it.
0OQIfcz.jpg
 
What kind of disadvantages do you see?

I was thinking about doing it to help with the starting issues. It is just slow to start and seems like it is weak starting up. I have replaced the carb, the coil, plugs, etc. That is the only reason I thought maybe going to 12v would help. Otherwise I agree... if it ain't broke, don't fix it.
 
Dad's 1958 Ford 641 still has the 6 volt system. Starts easily in Ohio winters. Still has original generator (rebuilt twice or so). Original starter (rebuilt once?). Battery is over 10 years old. I'm a fan of leaving it 6 volt. Keep all connections clean and tight.
 
6v is always slow but it will still crank fine IF everything is in perfect shape. That's a big IF and the older it is the worse it gets.

The biggest problem with 6v systems is voltage drop when cranking. It drops on everything whether 6v or 12v. If I remember correctly 4 1/2v is the absolute minimum for the points to fire correctly. That's a small drop and that's why your cables are so much bigger than on a 12v system. If your wiring isn't just like new or their connection points aren't shiny and clean your voltage drops more. Any wear at all on the starter will drop the voltage to far also. There's just too many things that have to be kept perfect for it to be reliable especially if it isn't kept inside.
 
(quoted from post at 10:56:42 11/11/22) What kind of disadvantages do you see?

I was thinking about doing it to help with the starting issues. It is just slow to start and seems like it is weak starting up. I have replaced the carb, the coil, plugs, etc. That is the only reason I thought maybe going to 12v would help. Otherwise I agree... if it ain't broke, don't fix it.

Check all wiring connections to make sure they are clean, bright and tight. Make sure that you are using #00 gauge battery cables for both the hot and ground side, and from the solenoid to the starter.
 
Biggest disadvantage to nearly all 12V conversions is the greatly increased shock loading to starter drives and ring gears produced when one operates a 6V starter from a 12V battery.

Slow to crank? If so, battery cables? Need good 0 or or 00 cables for 6V. AWG 4, 12V cables will drop voltage causing slow cranking.
 
Agreed. All of my vintage Fords are 6V, and all crank and start as they should.

A properly maintained 6V system is adequate and reliable.

This is not to say that a 12V conversion will not temporarily cover up a multitude of sins.
 
What is the voltage in your car, lawn tractor, boat, 4 wheeler, snowmobile or motorcycle?
Why have an oddball machine that can't jump or be jumped by anything else you own?
A typical 12V alternator conversion puts out at least twice the amount of power that a typical 6V generator does.
An alternator uses a solid state voltage regulator instead of the creaky old system of points and electromagnets used in an old fashioned mechanical voltage regulator.
An alternator lasts at least twice as long as a generator will and needs zero maintenance.
It costs about 1/3 the $ to replace an alternator compared to having an old generator rebuilt.
If an alternator goes bad it can be replaced the same day. A generator may take weeks to send out for a rebuild.
Alternators use a simpler wiring harness.
12V will spin your engine over faster and start it better.
12V batteries are off the shelf items whereas 6V batteries are often special order now days.
12V batteries will usually have a better warranty.
New 12V battery cables are also off the shelf items.
Big as your thumb 6V cables are not.
12V gives you vastly more and better lighting options and will allow you to run an array of modern add ons.
The primary reason for staying with 6V is sentimentalism - it was Dad's or Grandpa's tractor, etc. But I'm not sentimental...
 
Converted my Jubilee to 12 volt about 8 years ago. Tractor was always tough to start. Starts now with just a tap of the starter.

6 volt systems, when everything is in great shape, work well, but as things get old, current doesn't pass thru like it used to. Experiments done on the 6 volt tractor lead me to believe that when the tractor is cranking slow, it robs voltage from the ignition system and spark can be weak at that critical time.

If you convert.....do it right. Replace the coil with a 12 volt coil so you don't have to deal with the resistor.

As one guy mentioned a while back........one more advantage.......you can jump start your truck from your tractor now !

If you are contemplating conversion, the day the battery, or generator, needs replacing, do it then, as you won't be replacing a perfectly fine system.
 
Converted my Jubilee to 12 volt about 8 years ago. Tractor was always tough to start. Starts now with just a tap of the starter.

6 volt systems, when everything is in great shape, work well, but as things get old, current doesn't pass thru like it used to. Experiments done on the 6 volt tractor lead me to believe that when the tractor is cranking slow, it robs voltage from the ignition system and spark can be weak at that critical time.

If you convert.....do it right. Replace the coil with a 12 volt coil so you don't have to deal with the resistor.

As one guy mentioned a while back........one more advantage.......you can jump start your truck from your tractor now !

If you are contemplating conversion, the day the battery, or generator, needs replacing, do it then, as you won't be replacing a perfectly fine system.
 
If you convert.....do it right. Replace the coil with a 12 volt coil so you don't have to deal with the resistor.

I totally disagree with that statement. Using the original 6 volt coil with a ballast resistor allows you to use a bypass circuit to provide the full 12 volts to the coil when starting, which makes it even easier to start.
 
I must admit I was pulling your leg a little, but dang I have to go check that out! Even if it is only 24 months. Wonder if they have any group 31 there. The price I stated was Duralast, auto zones middle grade battery.
 
(quoted from post at 12:15:01 11/12/22)
If you convert.....do it right. Replace the coil with a 12 volt coil so you don't have to deal with the resistor.

I totally disagree with that statement. Using the original 6 volt coil with a ballast resistor allows you to use a bypass circuit to provide the full 12 volts to the coil when starting, which makes it even easier to start.
or sure and all you need is one simple diode! :D
 
(quoted from post at 09:46:48 11/13/22) ..

You might consider upgrading the starter to 12V also.

https://www.youtube.com/watch?v=jn7d-KZsIxs

I don't know for sure, but I would venture a guess that there are many more 6 volt starters that have been running fine on 12 volt systems for 20 years or more than those that have failed. Also, a number of the ones that have failed probably would have failed if they hadn't been converted to 12 volts.
 
(quoted from post at 09:59:03 11/13/22)
(quoted from post at 09:46:48 11/13/22) ..

You might consider upgrading the starter to 12V also.

https://www.youtube.com/watch?v=jn7d-KZsIxs

I don't know for sure, but I would venture a guess that there are many more 6 volt starters that have been running fine on 12 volt systems for 20 years or more than those that have failed. Also, a number of the ones that have failed probably would have failed if they hadn't been converted to 12 volts.
y 8N is going on past 22 years on 12v and same starter. Second 8N , not as many years (15) but just fine, too on 12v.
 
This "extra" field was reported to be a shunt coil. How would it be wired and does it have anything to do with converting 6 to 12v?
PBfOSrG.jpg
 

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