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Need help with ballast resistor/distributor wires.


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Hi all, after doing extensive research to no prevail, I decided to actually ask for help haha.

I have a 1976 620 that I recently rebuilt. Everything has gone relatively smooth except for the distributor/ ballast resistor wiring. I went with an internally resisted 12V coil and have since removed the ballast resistor. I am confused as to what to do with the remaining wires. Out of the main coil there is a black/red wire, black/white wire, and a blue wire that need a home. There is also 2 wires (Red and Green) coming off the spade connection of the side of the distributor. Any and all help is much appreciated!


Thank you, 




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 If you have the original coil, put it back on and keep the ballast resister. The original coil is 1.5 ohms and 1.5 for the ballast. When running power, it first goes through the ballast and then the coil, and 'sees' 1.5 + 1.5 = 3.0 ohms. But during start, there is a separate 12v signal while the starter is turning that by passes the ballast and powers the 1.5 ohm coil directly. This will produce a much hotter spark during start. You can't run it like this all the time or the points life is shortened and the coil over heats, but for starting it's fine.


By running a coil with an internal ballast you miss out on this hotter spark during start.


But, if you are determined to run this, simply join the two wires that were attached to the ballast and away you go.





Original equipment on a Datsun is always superior to after market parts quality. 

Avoid replacing original equipment unless positively proven to be broken and then never throw it away.

If replacing something, try as hard as you can to get an original part, even if used.

New, is no guarantee it works or is any better.

Don't throw parts at a problem, it's expensive, it's a gamble and you may put a bad part on compounding the original problem. Figure out what's wrong first and be sure.

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Gotcha, I apologize as I am trying to understand. If I want to run without the ballast resistor, I can join the blk/wht, blk/red, and blue wires together? I am curious which wires connect to the coil and if I just leave the red and green wires connected to the spade on the side of the distributor.


Thanks again.

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Ha Ha, I hear you. I've just been trying to clean up the engine bay and i'm not a huge fan of how that ballast resistor looks, but I guess I need it. I'll try to get some photos uploaded to day of my progress, still no luck on the wiring.

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The Black/Red wire from the ignition switch has power when in the ON or START position.


The Black/White wire also from the ignition switch has power when in the START position only.


If still going with the internally ballasted coil, join these two wires together and connect to the coil positive terminal. Hainz is correct. You will have a weaker spark when you need it for starting. Nissan engineers know best.

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Be honest I dont know this set up . Looks hacked up to me.

I know the Datsun Z cars used a 3 contack ballast resisitor. But I never learned how it worked unless Mike can explain it.


the green and red are just shorted together at the distributor/ where thy go to?YOu have a Tach? One can just route that to the minus side coil.   and it should work but this is so conveluded I say if it work right now dont change it untill you know where things go


I really dont know. I thought it was simplier  but I think adding a higher resisitance coil  will make it harder to statrt.  the stock point coil will be lower and with ballast makes it appear to be the higher coil. but during start the ballst is not in the circut thuse MORE spark. then when key to ON it will go thru the ballast and to coil

Edited by banzai510(hainz)
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