where to place balist resistor

roger hall · Aug 25, 2014

worked on a m today and noticed a resistor was in the wire between coil [neg side]and distributor points ---d21 plugs were sooty---is this where it belongs?

Bob · Aug 25, 2014

OEM ballast resistors are ALWAYS between the ignition switch and the coil.

Some argue they work just as well in either location, but I suspect having them between the distributor and the coil MAY shorten point life, as that puts a series resistance into the coil-to-condenser circuit.

http://www.cleancomputes.com/Cub/Bl...FOS-20 Chapter 6-Ignition Circuits/index.html

http://www.cleancomputes.com/Cub/Blue Ribbon Service Manuals/GSS-1310 Electrical/index.html

Achodges1 · Aug 25, 2014

Resistor belongs in front of the coil. Cuts the voltage from 12v to 6v. Only needed if system is 12v with a standard coil with no built in resistor. If still 6v system it's not needed at all. Sooty plugs usually means a rich mixture, but it has been my experience that a little rich is better than to lean.

FBH44 · Aug 25, 2014

Seems there was a post recently somewhere about a resistor that got rained on, and quit working until it dried off.... might mount it in a dry location someplace.

John T · Aug 25, 2014

Yo Bob, Ive seen those same arguments and often wondered myself. as far as reducing current in the primary circuit it works the same regardless of location, but I tend to agree with you about the points and condenser and coil ringing that goes on when the points open then sort of bounce a bit when closing. if the ballast is between the coil output and points looks to me like that affects the ringing and the circuitry and all that changes versus if it were out of that oscillation circuit, but ive never analyzed it very deep I STILL AGREE WITH YOU HOWEVER FWIW.....

John T

Janicholson · Aug 25, 2014

I agree as well. Kettering based ocillations are important. Jim

roger hall · Aug 26, 2014

thank you all for your input!!first time I ever ran across this set up--- thanks again! roger

where to place balist resistor

roger hall

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Bob

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Achodges1

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FBH44

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John T

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Janicholson

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roger hall

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