6 volt change to 12 volt

General help and support for your Lindeman through 2010 John Deere crawler
AllenS
420 crawler
420 crawler
Posts: 43
Joined: Thu Jun 28, 2012 7:11 pm
Location: Star Prairie, WI 54026

6 volt change to 12 volt

Post by AllenS » Mon May 21, 2018 7:14 am

Would like to change from 6 to 12 volt battery with negative ground on my 40C. Any good advice on how to do it?

B Town
1010 crawler
1010 crawler
Posts: 302
Joined: Fri Dec 11, 2015 7:04 pm
Location: Western Iowa

Re: 6 volt change to 12 volt

Post by B Town » Mon May 21, 2018 8:15 am

Is it currently a negative grounded system?

User avatar
Stan Disbrow
350 crawler
350 crawler
Posts: 2548
Joined: Fri Jul 15, 2005 3:13 pm
Location: Raleigh, NC

Re: 6 volt change to 12 volt

Post by Stan Disbrow » Mon May 21, 2018 9:03 am

Hi,

Original would be positive ground. All 6v were positive ground. Early 12v were pos gnd also, but shortly changed to neg gnd. I recall a 47 Ford fire truck we had in the local dept which was 12v pos gnd. It may have been that 12v began on industrial equipment much like 24v is used on some stuff these days.

If you do this, spend the money to convert the starter to 12v. Don't do what seemingly everyone does and run the original 6v starter on 12v (and, BTW the starter isn't polarized, just the generator and regulator). I just watched someone kill their ring gear at a old equipment show this weekend from using a 6v starter on 12v. The other thing 12v on a 6v starter does is bust the nose cone of the starter. Those are unobtainium these days.

On top of that, the right way is to also convert the generator and regulator to 12v as well. Using a more modern alternator works, but does not look right at all. This, if you plan on going to shows. If it is just for running, then the alternator route is fine. Use a 1-wire alternator with a new wire added between the alternator and the battery. Unhook all the old generator wires, clip their ends off, and put some heat shrink over the ends.

You need a ballast resistor in line with the coil so it doesn't cook along with the points. Or, just use a modern 12v coil. Of course, change your bulbs too. ;)

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

B Town
1010 crawler
1010 crawler
Posts: 302
Joined: Fri Dec 11, 2015 7:04 pm
Location: Western Iowa

Re: 6 volt change to 12 volt

Post by B Town » Mon May 21, 2018 11:18 am

I agree with all that Stan has stated. Yes, 6 volt systems started as pos ground. May have have been changed to neg ground. To provide concise instructions, I wanted to know the systems current configuration. Best regards, Bruce

User avatar
Stan Disbrow
350 crawler
350 crawler
Posts: 2548
Joined: Fri Jul 15, 2005 3:13 pm
Location: Raleigh, NC

Re: 6 volt change to 12 volt

Post by Stan Disbrow » Mon May 21, 2018 12:17 pm

Hi,

True. Someone could have repolarized the generator to negative ground.

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

User avatar
1954cooter
420 crawler
420 crawler
Posts: 45
Joined: Sat Oct 27, 2012 6:11 pm
Location: New Brunswick, Canada

Re: 6 volt change to 12 volt

Post by 1954cooter » Mon May 21, 2018 1:22 pm

When I changed my 420 over to 12v,I used the 6v generator but changed regulator to a 12v one.
The orginal JD 6v gen has a third brush so was able to get 12v from gen.It charges a little
less than 13v and with a small battery and small cables,starter is not hitting hard at all.Polarized
the charging system after I got it wired up.Its also neg ground now also used a 12v coil and a ballast resister.

Cooter

User avatar
Stan Disbrow
350 crawler
350 crawler
Posts: 2548
Joined: Fri Jul 15, 2005 3:13 pm
Location: Raleigh, NC

Re: 6 volt change to 12 volt

Post by Stan Disbrow » Mon May 21, 2018 3:14 pm

Hi,

The 420 gen was two-brush with a 2-bobbin regulator behind the tin dash plate. The M was a 3-brush gen with a 1-bobbin cutout relay behind the cast iron dash. Someone must have changed that one out for an older one somewhere along the line.

Yes, you can move the 3rd brush to get to 12v as long as you don't need to run lights much. As it was at 6v, the 3-brush gen had only enough power for two lights.

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

User avatar
shinnery
2010 crawler
2010 crawler
Posts: 717
Joined: Fri Jan 27, 2006 4:55 pm
Location: Hawley, Texas

Re: 6 volt change to 12 volt

Post by shinnery » Mon May 21, 2018 7:03 pm

If you are changing from positive to negative ground or negative to positive ground and have an ammeter to indicate level of charge you will need to switch the wires on the ammeter. I have a MM M-670 that indicates discharge when actually charging. I know what is happening but it freaks others out. LOL
No trees were hurt in the creation of this message.
But, many electrons were terribly bothered.

440IC/602, 2-440ICD/831 MM UBU-LP, 445N-LP, 445E-LP, BIG MO 400-M, 4 Star-LP M5-D, M5-LP, M602-LP, M670-LP, G900-LP, G900-D, G1000 Vista-LP Case 580CK

User avatar
Stan Disbrow
350 crawler
350 crawler
Posts: 2548
Joined: Fri Jul 15, 2005 3:13 pm
Location: Raleigh, NC

Re: 6 volt change to 12 volt

Post by Stan Disbrow » Mon May 21, 2018 7:20 pm

Hi,

I forgot about the ammeter. Yes, it would read backwards. Won't read charge at all if one runs a wire from an alternator to the battery, even though it is charging. Will still read discharge in that case because machine load (ignition, lights) still will come thru the ammeter. Well, read charge instead of discharge if the wires weren't flipped.

Now, that would be quite the confusion. Always showing charge and never discharge even though to the meter, it is always a discharge path!

If I were making the conversion, I would swap out the ammeter for a voltmeter. I can tell a lot more about the state of the alternator, starter, battery, etc with a voltmeter than I can an ammeter. There are times I tape a voltmeter where I can see it on everything I have which doesn't already sport one. I have one on my JD350C right now (reading volts in the dark in the barn because it is connected to the battery posts). Been eyeballing the system since the machine is new to me. ;)

I buy these cheap LCD voltmeters at hamfests and then calibrate them in my electronics lab. Handy things to have.

Stan
There's No Such Thing As A Cheap Crawler!

Have: '58 JD 420c 5-roller w/62 inside manual blade
Have: '78 JD350C w/6310 outside manual blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Also Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

User avatar
1954cooter
420 crawler
420 crawler
Posts: 45
Joined: Sat Oct 27, 2012 6:11 pm
Location: New Brunswick, Canada

Re: 6 volt change to 12 volt

Post by 1954cooter » Tue May 22, 2018 1:18 pm

I had swapped out the ammeter for a black rimmed voltmeter and
actually looks like it belongs in the dash next to the JD water temp gauge.
Voltmeter way better than ammeter,but that's just my opinion.

Cooter

Greasy1
MC crawler
MC crawler
Posts: 3
Joined: Sat Oct 29, 2016 5:46 pm
Location: Shelby NC

Re: 6 volt change to 12 volt

Post by Greasy1 » Tue May 22, 2018 7:54 pm

I have bought three pieces of equipment cheap because they had bad 12v conversions. Most do not understand that just adding a resistor to the coil is not the proper way to assure proper firing voltage. Which resistor do you add, 1.5ohm,3ohmor 5ohm. Depends on the voltage and type of coil construction. To make it simple the total resistance of the coil and any resistor should not exceed 3.5 to 4 ohms. Any more resistance and there will not be enough voltage to properly fire the plugs. Also check the wiring polarity of the coil. Positive terminal goes to ignition switch, negative goes to polnts. If it is not a show machine,loose the generator and install a 65 amp 1 wire alternator with a voltmeter. I just finished this on my 420 loader. The total cost minus the battery was approx $100.
Best of luck,
Mark
Hooked on crawlers when I worked on my first Euclid. Just bought 1957 420c

User avatar
notmeu
1010 crawler
1010 crawler
Posts: 344
Joined: Wed Dec 28, 2011 2:23 pm
Location: Western PA

Re: 6 volt change to 12 volt

Post by notmeu » Fri Jun 01, 2018 10:03 am

When I changed my 420 over to 12volt the coil had to be a 3ohm. But I think it was because I installed a electronic points kit in the distributor verses mechanical points. But I somewhat remember the resistor had to equal 3 ohms, I may be wrong though, It’s been a while. The electronic points have been trouble free for years though.
1956 JD420, gearmatic 8a winch, custom 6 way blade and FOPS.

User avatar
notmeu
1010 crawler
1010 crawler
Posts: 344
Joined: Wed Dec 28, 2011 2:23 pm
Location: Western PA

Re: 6 volt change to 12 volt

Post by notmeu » Fri Jun 01, 2018 10:05 am

notmeu wrote:
Fri Jun 01, 2018 10:03 am
When I changed my 420 over to 12volt the coil had to be a 3ohm. But I think it was because I installed a electronic points kit in the distributor verses mechanical points. But I somewhat remember the resistor had to equal 3 ohms, I may be wrong though, It’s been a while. The electronic points have been trouble free for years though. I also have the original 6volt starter and never changed it over to 12volt and it also has been running trouble free.
1956 JD420, gearmatic 8a winch, custom 6 way blade and FOPS.

Greasy1
MC crawler
MC crawler
Posts: 3
Joined: Sat Oct 29, 2016 5:46 pm
Location: Shelby NC

Re: 6 volt change to 12 volt

Post by Greasy1 » Sat Jun 09, 2018 7:22 am

Sorry for the lateness of my follow up. The coil/resistor resistance has nothing to do with points versus electronics. Total resistance has to do with firing voltage at the spark plugs and wether it will reliably jump the gap. As an example I purchased a tractor that had been converted to 12v that after the conversion could only be started by pushing. The original 6v coil was still in place and a new dropping resistor of 5ohms was installed. Total resistance was 7 ohms which provided a coil input voltage of under 2 volts, enough to run marginally, however with the starter engaged this dropped to less than 1 volt and the plugs would not fire. When I went to get the tractor took a 12vcoil with 3 ohm resistance and 10 minutes later started the tractor and drove it onto the trailer. Same problem with my 420 when I bought it, except it still had the positive ground regulator still installed.
Hooked on crawlers when I worked on my first Euclid. Just bought 1957 420c

User avatar
RacinJason
430 crawler
430 crawler
Posts: 62
Joined: Wed Aug 29, 2012 6:41 am
Location: Spfld, MA/ Corinth, ME

Re: 6 volt change to 12 volt

Post by RacinJason » Tue Jul 24, 2018 5:48 pm

My 420C had a 40 engine, and as I mentioned in other posts, it stopped running a couple months ago. Seemed like an ignition problem, but, as it had 85 lbs. pressure in one cylinder, and smoked a bit (what mosquitos?) I put in another used engine, with the help of T. Briggs, whom some of you may know. After I got everything hooked up, it still wouldn't run. Well, I had seen it run in the past, so I knew it wasn't the engine, and I was using my carb and distributor, so I attempted to install a new bushing in the distributor, but would need an adjustable reamer. Went through this in another post. As I was getting intermittent spark, I decided to install the Pertronix Igniter, and the 12 volt Flamethrower I had ordered while back in MA. Voila, I now have a fine running dozer. I have read a lot of posts here about engines not running because of ignition problems. I think my main problem was the points and condensor. I had replaced them and noticed the distributer shaft was loose in the bushing, making a good adjustment impossible. After I flipped the bushing, I think the main problem was a bad (new) condensor. I should have tried the original one I had replaced, but, now I'm happy with the Pertronix. I'm running a basic ignition system, right off the battery, with an on/off switch, alternator not hooked up (yet), and a 12 volt Optima.
JD 112, JD 420 C

Post Reply

Who is online

Users browsing this forum: No registered users and 8 guests