Yesterday's Tractor Co. Shop Now
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Classified Ads
Photo Ads
Tractor Parts

Discussion Forums
Project Journals
Tractor Town
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs

Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
Farmall & IHC Tractors Discussion Forum
Show Parts for Model:

Re: Ih460 wiring ,coil question

[Show Entire Topic]  

Welcome Guest, Log in or Register
Author  [Modern View]
John T

01-30-2013 06:21:16

Report to Moderator

If a coil is labeled "12 Volts" or "12 Volts NOT for use with Ballast Resistor" or "12 Volts NO Ballast Required" etc on a 12 volt tractor YOU DO NOTTTTTTTTTT USE A BALLAST OR THE SPARK WOULD BE VERY WEAK....

If a coil is labeled "6 Volts" or "12 Volts for use with Ballast Resistor" or "12 Volts requires Ballast" etc on a 12 volt tractor YOU NEED AN EXTERNAL SERIES VOLTAGE DROPPING (12 to 6) BALLAST or else the coil overheats and the points burn rapidly.

Om many 12 volt tractors a 6 volt coil plus an external ballast is used so during cranking the ballast can be bypassed (like an extra I terminal on starter solenoid etc to feed coil direct bypassing ballast while starter is engaged) which helps cold weather starting.

If your ballast was by passed someone likely put on a 12 volt coil (instead of correct 6) and did away with the by pass circuit. It will still work okay as is with poorer starting spark in cold weather as if wired correctly with 6 volt coil and solenoid by pass

Contrary to what many lay persons believe, you most likely will NOT find any discrete stand alone "resistor" hidden away inside the coil can. A 12 volt coil has around 2.5 to under 4 ohms primary resistance while a 6 volt coil has more like 1.25 to 2 ohms

Myself and Bob M and Janicholson have explained this hundreds of times on here do a search for more info if needed

That help?? Any more questions?? See URL link below for more

John T

[Log in to Reply]   [No Email]

01-30-2013 18:15:38

Report to Moderator
 Re: Ih460 wiring ,coil question in reply to John T, 01-30-2013 06:21:16  
John T, I read all your info on coils. So I had a little time this evening to go out to the tractor shed and look at the wiring again. Haven't had much time to work on it lately. When looking at the coil it wasn't stamped 6volts or 12 that I could see, very rusty and old looking (like me). I did see some wording that said,use with external resistor and there was a #27291 stamped on it. Since the tractor has 12volt system should i ask for a 6volt or 12volt coil to install on it? Thanks Larry

[Log in to Reply]  [No Email]
John T

01-30-2013 19:22:25

Report to Moderator
 Re: Ih460 wiring ,coil question in reply to LarryNMO, 01-30-2013 18:15:38  
"I did see some wording that said, use with external resistor"

If it says that my best "guess" is it means just what it says i.e. it requires the resistor or else it will overheat....Id try that coil WITH the unshunted external ballast n see what happens.

"Since the tractor has 12 volt system should I ask for a 6 volt or 12 volt coil to install on it?"

You can EITHER use a 6 volt coil PLUS the external series voltage dropping (12 to 6) working ballast orrrrrrrrrrrr a 12 volt coil with no ballast required. However to utilize the ballast by pass system for improved cold starting you would need the 6 volt coil plus a good ballast. Id be tempted to just use a new full 12 volt coil (NO ballast required) and do away with any ballast or by pass circuit headaches...

John T

[Log in to Reply]  [No Email]

01-30-2013 07:31:21

Report to Moderator
 Re: Ih460 wiring ,coil question in reply to John T, 01-30-2013 06:21:16  
Thanks John T for the info. I'm a shade tree mechanic (I think) with limited electrical expertise, but maybe I can digest all this info.

[Log in to Reply]  [No Email]
The tractor vet

01-30-2013 07:15:59

Report to Moderator
 Re: Ih460 wiring ,coil question in reply to John T, 01-30-2013 06:21:16  
The stock Coil for a Farmall is a 6 volt coil and the use of a resistor is used from the factory , on late model 706-806 the ceramic resistor was replaced with a resistor wire . A hot shot wire as i cll it was run from the R terminal on the solenoid to bypass the resistor to give a shot of 12 volts for fast start and hot spark. Now i am not and electrical engineer and maybe my way of doing something are shell we say barnyard engineering i try and follow the book with a few teaks here and there like i do away with the fuse and use self resetting curcit brakers add in C/V relays to take the load off the head light switch when someone want to add more lights then came from the factory since you pushing the factory switch to the max at five lights . I cringe at some of gen to alt. change overs that i have seen , Like running a 65 amp alt thru a 12 ga. wire and like the Farmer wire job that was hacked up on this 460 i am working on at this time . How these guys can sleep at night with something like this setting in a barn full of hay and fifty or so cows down below is unbelievable .

[Log in to Reply]  [No Email]

01-31-2013 18:07:48

Report to Moderator
 Re: Ih460 wiring ,coil question in reply to The tractor vet, 01-30-2013 07:15:59  
Tractor Vet, (I'm getting my electrical course on this webb site THANKS TO ALL FOR THE HELP) you indicated someone had installed a 65 amp alt with a 12 ga. wire on a tractor (not good). So I thought I better ask you. On my ih460 the alt was bad, had it tested. The alt had come off a 73 chev pu, it was marked what it came off by someone. Soooooooo I had one that came off a 75 pontiac 400cu in. that tested good and put it on the tractor. Now i do not know what amps it is pushing thru the wires and what size alt would that tractor use? DON"T WANT TO BURN DOWN THE SHED Larry

[Log in to Reply]  [No Email]
John T

01-30-2013 15:37:14

Report to Moderator
 Re: Ih460 wiring ,coil question in reply to The tractor vet, 01-30-2013 07:15:59  
Thanks for the info,I know many 12 volt tractors use the 6 volt coil and the ballast by pass while cranking, but I had no idea WHICH MODELS. The R or I (what Fords used) terminal on the starter solenoid is a terminal thats hot ONLY while the starter is engaged and it connects direct to the coil input so it sees unballasted battery voltage ONLY while cranking fOR TH hotter starting spark, its a good system if all is well...

Fun chat

John T

[Log in to Reply]  [No Email]
[Show Entire Topic]     [Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:

Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

Home  |  Forums

Copyright © 1997-2018 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