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Resisting the resistor


Drfixit

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I was given an electronic Ignition Kit for Xmas that the person bought on Ebay. Fairly simple install ,eliminates points has a box that mounts to the firewall and uses the existing coil. Installation wiring diagram did not show nor mention the ballast resistor which is wired into the existing coil. After I searched I am really confused. I think what I read was use the resistor with the existing coil and if you buy an aftermarket coil you can eliminate the resistor. Does any of this make sense? The kit is made by Montegomery Ward! (Thats scary lol) I put it in and it was real easy and starts easier and idles better so I guess I am OK just wondering if I am eliminating some of the spark "Power" by running power to the coil through the ballast resistor.

 

As Usual Thanks a bunch

 

Doc

Edited by Drfixit
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Yes it makes sense. The stock coil with resistor is designed to run at about 8 volts. Running without a resistor at 12 volts will overheat it, and it can explode. Any coil from a later EI setup is designed to work at full battery voltage without a resistor.

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Yes. The EI coil uses the full 12 volts for more output. Usually you open the plug gap to about 0.040" to take advantage of the hotter spark.

 

And the resister is to protect the points and the coil which are designed to work at about 8 volts. Without the resistor the current goes up about 50% and heats the coil and causes excessive arcing of the points reducing their life to a couple hundred miles or less.

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A wider gap means a longer spark to get things going. Make sure that your wires. cap, and rotor are good as opening the gap will force the system to exert more voltage to jump the gap specially at WOT. Electricity always looks for the easiest path to ground and if it's easier it will jump between wires or across the cap surface or even from the coil output to the neg terminal.

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Yes:

 

1. The resistor + coil are a set. Doesn't matter if you have electronic ignition or not. With EI, you can change resistor+coil to EI coil+no resistor -- if the EI is rated for it.

 

2. Plug gap is related to the Coil. Most EI Datsun coils use up to a 0.039-0.043 gap -- but you can still use a 0.030-0.035 (standard) gap. Newer Nissan coils use plug 0.054 gap but may burn out your EI box if it's not rated for super-high voltage coil.

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I was given an electronic Ignition Kit for Xmas that the person bought on Ebay. ... The kit is made by Montegomery Ward!

Monkey Wards?! :eek: Been ages since I've heard that name. Not surprising since they (the department store chain, not the current online retailer) went under in 2001.

 

Still have the heavy welding cable jumper cables I bought from 'em 30 years ago.

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