Posted by Bob on July 02, 2015 at 20:45:59 from (64.255.159.192):
In Reply to: Coil Polarity posted by Steve@Advance on July 02, 2015 at 19:41:28:
IMHO, coil/spark polarity makes NO difference in the starting of a cold engine.
But once the engine is running and warms up, the center spark plug electrode is HOTTER than the ground electrode, making it a better emitter of electrons (thermionic emission).
For this to work, the center electrode must be "fired" with a negative-going pulse.
Which is exactly what happens when the coil primary polarity is "correct".
In my experience, having the coil polarity correct CAN help prevent miss-fire under lean conditions, or full-load conditions, when the throttle is wide open and compression pressures are at their max.
On the other hand, many modern engines have a "waste spark" setup that fires two sparkplugs at the same time, one with a negative-going pulse, and the other with a positive-going pulse, and those engines run just fine. (I guess 'cuz they simply have a HOT spark to begin with!)
Also, typical old tractor magnetos fire every other plug with the opposite polarity. I wonder hoe many of my fellow tractor "GURUS" realize that?
Upload one or more videos to your post. Photo filesizes should be less than 300K and Videos, less than 2MB. Formats allowed are gif, jpg, png, ogg, mp4, mov, and avi. Be sure to use filenames without spaces or special characters, and filetypes of 3 digits lower case.
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 - New Hitches For Your Old Tractor - by Chris Pratt. For this article, we are going to make the irrational and unlikely assumption that you purchased an older tractor that is in tip top shape and needs no immediate repairs other than an oil change and a good bath. To the newcomer planning to restore the machine, this means you have everything you need for the moment (something to sit in the shop and just look at for awhile while you read the books). To the newcomer that wants to get out and use the machine for field work, you may have already hit a major roadblock. That is the dreaded "proprietary hitch". With the exception of the
... [Read Article]
Latest Ad:
2022 John Deere 5045E, 4wd, front end loader and 3rd function with grapple. 120 hrs, 55k new, must sell
[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.
