Posted by JMOR on August 04, 2012 at 20:30:03 from (99.105.24.57):
In Reply to: Help needed posted by Stick welding on August 04, 2012 at 08:32:43:
Quoting Removed, click Modern View to see"Finally, dont let anyone tell you it dont matter which polarity you wire a coil, its true she will still spark if wired bass ackwards, but its more efficient if wired at the correct polarity. If its a Neg ground tractor, + (Battery) on coil wires to switched ignition circuit (or ballast if used) while - (dist) wires to the distributor. Reverse that for Pos ground. "
That's right.......don't let anyone tell you anything unless they can fully explain why. And just connecting + to + and - to - is not going to guarantee you maximum voltage, even though it will yield a negative HV spark, Sir! It depends on the particular coil. If the coil was designed for a Positive ground system & you change it to a Negative ground system & leave coil wired as it was from factory, you get full voltage out, but a Pos polarity spark. Swap the coil wiring & you get your Negative spark, BUT at a lesser voltage, by the amount of voltage across the primary during the spark (typically 100:1 ratio). You can NOT have both neg spark & full voltage UNLESS you swap to a coil with a different winding sense/connection of primary & secondary, as in a coil designed for a Negative ground system. + to
+ and - to - alone will not cut it. This technology is 100 years old & still the information floating around is "what I've always understood/heard" instead of real hard fact. It is just amazing!
Another aspect that really kills the spark polarity aspect is that both the center & side electrodes are cold at start up, just when you need a hot spark the very most.
Further more, your old magneto tractors have every other spark output alternating +/- in polarity, as did all the old HD motorcycles, and many 'wasted spark' modern engines.........so just forget spark polarity, once & for all!!!
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 - Timing Your Magneto Ignition Tractor - by Chris Pratt. If you have done major engine work or restored your tractor, chances are you removed the magneto and spark plug wires and eventually reached the point where you had to put it all back together and make it run. On our first cosmetic restoration, not having a manual, we carefully marked the wires, taped the magneto in the position it came off, and were careful not to turn the engine over while we had these components off. We thought we could get by with this since the engine ran perfectly and would not need any internal work. After the cleanup and painting was done, we began reassembly and finally came to t
... [Read Article]
Latest Ad:
1965 International Harvester McCormick Farmall cub tractor 2,500. Two owner tractor. My grandfather bought new in 1966, then we inherited it. Have all the paperwork original manual and all maintenance records. It starts and moves. Comes with underbelly mower, plough, and some other attachments.
[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.
