Generally speaking with post-1940s coils, there is no such thing as a "6 volt system" or "12 volt system" coil. That because many systems, regardless if 6 or 12 volt, feed the same voltage to the coil under normal running.
What you need to determine is IF that coil needs an external resistor hooked to it when used on a 12 volt system.
You also need to know if it was designed for a system WITH ignition points, or for a more modern high-energy breakerless system. Such coils will have very low resistance across the primaries; often only 6/10ths of an ohm.
A typical OEM coil on an H that had 6 volts fed directly to it is checked as thus with an ohm-meter.
2.6 ohms across the primaries and 7000 ohms across one primary to the secondary.
Same coil was also used in 12 volt systems along with an external 1.8 to 2.2 ohm resistor.
A coil that has a built-in resistor is only good for use in a 12 volt system. It will measure around 4 ohms between the primaries.
Then you've also got the many "hot spark" coils made for older tractors. Often 1.4 ohms on the primaries and 10,000 ohms between one primary and the secondary. Can make 40,000 volts instead of the standard 20,000, but also can be hard on ignition points.
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 - Show Coverage: Godfrey, Illinois Country Days - by Cindy Ladage. Except for last fourth of July's Old Gold show in Springfield, Illinois, I don't remember when it was so hot. Nevertheless, the heat didn't keep vendors and visitors alike from enjoying the third annual Country Day's Event. Jane Elliott said the event was originally a one man show. "Barry Seiler, owner of Country Town Farm Supply store used to invite people up to the Johne Deere store. He would give hats and a free meal for everyone that brings a tractor." Elliott said while this
... [Read Article]
Latest Ad:
Sell 1958 Hi-Altitude Massey Fergerson tractor, original condition. three point hitch pto engine, Runs well, photos available upon request
[More Ads]
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.