(800) 853-2651
SHOP NOW

Verifying reversed polarity

L

LRRifleman

Member
Hello!

I have a 1958 International 340 Utility that was converted to 12 volt by a previous owner. After having the engine checked due to starting difficulty. I was told that both the starter and the voltage regulator were "fried". Fortunately, my local (agricultural) Case dealer can get the parts I need at a reasonable price. However, being on pension and disability, I want to do the work I am capable of by myself, so I can avoid the estimated $500 labor expense to replace the starter and voltage regulator!

When I spoke with the people in parts, I was told when the conversion was done (if it was done properly), the starter should have been rewound for a 12 volt system, and the ground polarity reversed, from a negative ground to a positive ground.

What should I look for on my tractor to confirm that the ground was switched from a negative ground to a positive ground? Is it as simple as tracing the positive lead from the battery to the ground point on the chasis?

Any and all constructive advice would be vastly appreciated!

Thanks, Ed
 
Ed,

The starter did not need to be rewound for 12V conversion. It will
work fine as is.

John T has published a procedure on converting, that should be
searchable. It is a very easy procedure, especially if an alternator
replaced the 6V generator.
 
The starter does not care if it is + or - ground and a 6 volt starter will work on 12 volts as long as you do not hold it in the start position for a long time. I have a 340 here that I converted to 12 volts and it still has the old starter on it and a Delco 10si alternator on it which is also easy to wire up.
 

Do I understand this correctly, that the polarity does not have to be changed to go from 6v to 12v? I can jsut drop in a new starter and voltage regulator, and I am good to go?

I love this tractor, and want to keep it running. I have it and a 1970 Massey 135, which beteween the two of them, should handle the retirement farm I want to get going and raise my kids on!

Thanks!
 
The non-solid state devices do NOT care about polarity.
Alternators and solid state regulators DO care bout polarity. Bets
are it is negative ground if it has an alternator.
 
(quoted from post at 19:05:15 05/27/12) Do what old says, make sure there is an alternator on it.
Click to expand...

Dave and "Old",

Thanks for the advice.

Sorry, this will sound dumb, but in the cloud of a severe concussion 5 years ago in what should have been a fatal auto accident, I can't for the life of me remember how to tell the difference between an alternator and a generator.

CAn someone "re-educate" me so I can tell the difference?
 
The Generator will be a cylinder approximately 4" in dia and 6.5 or so long. It will have two bolt on terminals on the side near the non-pulley end. and a metal band clamped around that same end covering the brushes.
An alternator will be aluminum (or painted aluminum) and be much shorter.
A magnet will stick to the outside of a generator on any surface, it will not stick to most places on an alternator. Most replacement 12v systems are alternators, and most of those used today have an internal regulator. Some early delco and ford alternators do have regulators seperate and similar to a generator. Jim
 
"When I spoke with the people in parts, I was told when the conversion was done (if it was done properly), the starter should have been rewound for a 12 volt system, and the ground polarity reversed, from a negative ground to a positive ground."

The parts people are wrong. If your 340 came with 6 volts (IH was changing to 12 volts in 1958), it was positive ground. A 6 volt starter works fine with 12 volts, no rewiring is necessary. I assume you have an alternator, if so it HAS to be negative ground. If it has a 12 volt generator, most are negative ground, but it will work with positive ground also-the generator must be polarized no matter what the ground is. You do not polarize an alternator. If your ammeter shows discharge with the engine running AND charge with the lights or ignition on and the engine off, reverse the wires on the ammeter.
 

Hello!

Providing multiple answers here.

I am just outside of Mays Landing, NJ.

Sadly, I believe it is just the tach that is operating. A previous owner removed the lights, there are none on it. As I remember the instrument cluster, I definitely know that neither the ammeter, water temperature, nor fuel guage are working. I can not be totally certain about the oil pressure guage.

Sadly, a lot of my skill went with my mobility in my accident ... trying to see what I can do with a small food plot on a friend's farm before I make the move onto my own farm ... my current 100% is about 65% of the pre-accident me. Part of what is keeping me going are the hopes to be able to do an acre or so food plot, 10 acres of Christmas trees, and about 10 acres of hay ... plus a few acres dedicated to ponies for my kids. Dreams are powerful medicine!

Sorry for the deviation and rambling!
 
I appreciate what you are saying. My dad was the best mechanic
until he had a stroke. He still had all the knowledge after that, but
could not make his hands do what he wanted. It was very hard on
him.

I am in Iowa, too far away to help.
 

Hi David,

Yes, Iowa is jud a tad out of range. Sorry to hear about your dad. My dilemma started when I rode my Harley to work as a teacher ... a Cadillac crossed the centerline and hit me head-on. I have a mutilated leg, a blown out knee, and a shattered and barely functional arm. Then, I underwent 19 months of abuse at the hands of my now ex-wife. So I now get to raise two children (6 & 4) by myself, and still try to pursue my dreams.

Life is slowly starting to get back to a semblance of pre-accident normality! Just preparing for the prospect of surgery 17!
 
Do a search on this site for "John T generator troubleshooting" to find John T's article. I printed out a copy and put it in my letter series I&T service manual.

Here is a generator:

jdgenerator.jpg


Here is an alternator:

AlternatorHarness4.jpg
 
You must log in or register to reply here.

Similar threads

P
300 u 6 to 12 v conversion update problem
2
Replies
28
Views
1K
Paul 300 U
P
M
SWD9 battery ground
Replies
7
Views
335
John T
J
N
6v8n generator connections
Replies
17
Views
529
Tim PloughNman Daley RIP
T
B
Question for pos/neg ground
Replies
10
Views
667
John Deere D
John Deere D
F
Voltage regulator question
Replies
12
Views
556
JMOR
J
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top