(800) 853-2651
SHOP NOW

Resistor wires on a magneto

C

Cameron Smith

Member
I have read several times on this forum to NOT use resistor type plug wires with a magneto but I"d like to know WHY! What kind of a problem do they create? Anyone know out there?
 
Just plain resistance in the material they are made from.

A conventional plug wire has a resistance of 10,000 to 15,000 ohms per foot of length.
The more resistance the weaker the spark.

These wire are also shielded to prevent radio and TV interferance.



For best results use solid copper wire plug wires.

Verym, very low resistance.
 
Cameron, insulation technology wasn't what it is today back in the magneto era.

Resistance wires make the voltage at the mag reach much greater peaks than with solid wires, potentially leading to an early demise of the coil inside the mag.

Some old mags even had internal spark gaps set a little wider than the sparkplug gap so the spark could jump harmlessly to ground if, for instance, a plug wire fell off, rather than seeking a destructive path to ground through the insulation in the coil or the distributor cap.
 
Cam, to begin with a Magneto doesnt have all that much energy to spare, and you DO NOT want to waste any of it (even if negligible) in the form of I squared R energy Heat Loss in resistive plug wires, better to expend as much as possible across the plug gap to ignite the fuel. Also as Bob and others noted, theres the accompanying greater voltage drop across resistive carbon core suppressor plug wires then in pure copper plug wires (V = IxR). Finally, the inductive output of the mag (HV Coil secondary) would be looking into a higher impedance (then original design) if you were to use resistive plug wires.

Thats my story n Ima stickin to it

John T
 
You must log in or register to reply here.

Similar threads

J
JMOR, A resistor question.
2
Replies
35
Views
1K
JMOR
J
K
How to rewire fuel pump when removing external resistor
Replies
1
Views
173
BarnyardEngineering
BarnyardEngineering
K
How to rewire fuel pump when removing external resistor
Replies
13
Views
487
used red MN
U
R
48 Cub still not starting
Replies
9
Views
328
Keith-OR
K
63mercragtop
Farmall A 1941 Magneto Conversion
2
Replies
26
Views
895
teddy52food
T
Tractor Parts Tractor Manuals

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.

Copyright © 1997-2024 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
Website Accessibility Policy

Back
Top