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Hey everyone! I have been working on trying to get my 1967 Dodge D100 slant six with the old points and condenser started up. I apologize if I missed anything in a previous post or if I ask a silly question here but I have a limited knowledge of vehicle electrical systems.

I have been having an issue where I am not getting any spark and I think I have possibly narrowed it down to either a bad ignition switch or an issue with the wiring. I tested the voltage at the battery and I am getting 12.5V. At the one leg of the ballast resistor, I get the same voltage but on the other side I only get about 8.5V. Somehow, I am getting 11.4V at the coil though which puzzles me a little bit since I only get 8.5V on the one side of the ballast resistor. Shouldn't I get the same voltage at the coil as what I get at the ballast? At any rate, I am at a bit of a loss but I am pretty sure that I need to fix up some wiring and possibly rule out the ignition switch as the issue. Other than getting a new ignition switch how can I verify it is good? Also, if I have to redo wiring from the bulk head back, what is best way to go about this since the factory originals where molded into rubber/plastic boots??

Thanks ahead of time for your time and for the help you provide everyone on here!

With the key On there should be voltage at the coil, through the ballast. While cranking the ballast is bypassed & the coil gets a full 12 volts until you release the key & the ign switch returns from start to run.

Since you are getting power at the coil (and at the starter) I would say the ignition switch is ok.

Possibly the coil itself is bad or something in the distributor.

Are you certain you are not getting spark?

Bucky

Hey Bucky,

I am pretty positive. I bypassed the ignition and hotwired the coil straight to the battery quickly and I had a full voltage at the coil but I could not get a spark when I stuck a screwdriver down the center of the coil.

The engine turns over but it never fires. If I pull the lead off the center of the distributor and hold it near the block I also get no spark. Its driving me insane haha

Did u install new points (correctly gapped) and condensor? If not, don't bother with anything else.

I have not. I will do that this afternoon and see what happens. How can I test the coil to be 100% certain it is good?

Alright, so I finally got around to replacing the points and condenser and it unfortunately did not fire up. I triple checked the gap just to make sure that was set properly but I still get no spark from the coil. I tested the coil for resistance and it is good. At this point, since I am going to ditch the 6 and go with a 318 setup, I think I will just let it go. I was just hoping to prove that the engine was indeed good for whoever may want to buy it. Thanks for everyone's help!

Explain your gap setting process.
Is there 12V at the points when they are open? 0 when they are closed?

Typical points ignition can be hot wired to make it run. You don't need an ignition switch or any wiring to do that. Put power to + side of coil and then check points for spark. If you have fuel and air it should fire up. You could start up engine with it sitting on the ground doing it that way.
I have done that many times to see if an engine runs.
If you want to run for awhile, Just hook up a radiator. Micky Mouse it all the way to make it run.

Exactly as Kim says!
But he did say he has +12 at the coil, so there is something else wrong.

To confirm, do you have +12 at the coil WHILE CRANKING?

Ok, so I took more careful measurements by employing the help of my daughter and at the coil while cranking I am only getting 8.6 volts. Also, I turned the ignition to on but not cranking and was still getting 8.6 volts at the coil. Should I be looking at the switch or possibly running fresh wire on both sides of the firewall?

Something I would check is if points spark when turning over with cap off. No sparky, You have a problem there. Either no power. Incorrect gap. Dirty points. Bad condenser.

PwrWgnDrvr wrote: ↑

Tue Feb 27, 2018 10:45 am

Explain your gap setting process.
Is there 12V at the points when they are open? 0 when they are closed?

You really need to answer this that I posted earlier today!
That is the same as Kim's suggestion tonight.
The wire from coil to distributor to points can also be open (broken internally).
The 8V measurements are also weird. You need to run a hotwire directly from battery + to the coil. That will bypass everything else and eliminate all the other wiring, switch, ballast, etc.