Posted by JMOR on November 12, 2012 at 10:03:38 from (72.181.173.171):
In Reply to: Ford 8N Starting Problem posted by Self-Insured...John,PA on November 07, 2012 at 16:50:38:
Quoting Removed, click Modern View to seeThe first rule is ...if it ain't broke, don't fix it, especially after it has been fine for 6 years.........
IF you really have a true 12v coil, which requires no resistor, it will have a primary winding resistance of about 3 Ohms, some as high as 4, which by design limits point current to about 4 amperes, which is a safe operating current for thew points, so no resistor required. Just because a coil is sold for a 12v application (for example a 1971 Ford PU) does not mean that it is a "true 12v" coil. The Ford PU is a 12v system, but the coil has about 1.3 Ohms resistance, which if used without an external resistor would produce about 10 amperes through your tractors points, leading to a very short lifetime! The PU has a resistor built into the wiring harness with a special high resistance wire & high temperature insulation and it has the current switched by a transistor, not points.
Hopefully, you can see why emphasis is placed on the words, "true 12 volt". It would be a lot more useful to use words such as a "1.3 Ohm coil", a "3.2 Ohm coil", or a "a 0.47Ohm coil", etc. than to say a "12 volt coil", because with the simple 12v coil description, you really don't know what you have in your hand. Some will have additional information, such as "use with external resistor", or "no external resistor required", but not all manufacturers are so good as to include this kind of marking on their coils. Hope educational for you.
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. [ About Us ]
Today's Featured Article - Identifying Tractor Noises - by Curtis Von Fange. Listening To Your Tractor : Part 3 - In this series we are continuing to learn the fine art of listening to our tractor in hopes of keeping it running longer. One particularly important facet is to hear and identify the particular noises that our
... [Read Article]
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.