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Discussion Starter #1
After 5 months of rebuild my 67 Fairlane is operational and my 289 runs! I did find my old distributor was not keeping the timing so I replaced my distributor and coil with an MSD one.

I have the MSD distributor and coil installed and was unsuccessful at getting the car to start. I later learnt that the distributor requires 12 volts. However when I checked the voltage of the wire going from my ignition to my coil it is only 8 volts. So I tried running a wire directly from my positive battery to the coil and it fired up perfectly. However I was unable to shut the car off with my key.

So I am trying to figure out what options the experts would recommend to enable me to get 12 v to my coil?

It would be great to get some advice from the experts here.

46273
 

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The stock system runs on reduced voltage from the ignition switch. The current flows through a resistance wire after it leave the ignition switch and to the coil. This is to protect the coil. During starting full battery current comes from the starter relay to the coil by-passing the resistance wire.

If you want a key operated 12 volt source, run a new wire from the ignition switch to the coil and by-passing the resistance wire. You can leave the stock wire connected as no damage will occur to the resistance wire. And this would allow the option to switch back to stock at a future point.

The other option would be a separate interior mounted switch. Pull current from fuse box, run to a switch and then to the coil. Easier to wire and an add step to start/stop the vehicle. But it would add a layer of security or anti-theft

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Discussion Starter #3
Thanks Action for the quick reply! This makes sense. I think I will route a new wire from the ignition switch. Will post once I get this totally figured out!
 

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Shoot a pic of the switch to post here. Others will be interested.

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Discussion Starter #5 (Edited)
Action I have attached a photo of my ignition switch and wires.

From what I can tell there is a red, yellow, red and blue stripe wire and then there is the black and pink wires at the back of the ignition. And that goes to this round gold device.

I believe the red one is currently going to my coil.

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The gold devise is a flasher. (Turn signal or emergency)

In the bottom pic look like the back side of the ignition switch is showing. That stud would be for accessories. Meaning it will be hot when the switch is on and when the switch is in the accessory position. It would be easy to connect a wire there using an insulated wire terminal with an open end crimped to the wire going to the coil.

This will NOT provide power to the coil while cranking the engine. For that you will need to keep the existing wire on the coil. That wire comes from the starter relay.

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Discussion Starter #7 (Edited)
Action just to ensure I understand. I can attach a new wire from the back of my ignition switch that will run directly to my coil. Then on my coil I will have three wires on the positive terminal. 1. existing one to my coil from my ignition, 2. one from my distributor and 3. this new one from the back of my ignition switch.

And this new wire will be 12 v?
 

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Action just to ensure I understand. I can attach a new wire from the back of my starter that will run directly to my coill.

Then on my coil I will have three wires on the positive terminal. 1. existing one to my coil from my ignition, 2. one from my distributor and 3, this new one.

And this new wire will be 12 v?
You have typed the word starter twice.
Once above and once in post #5
Do not use the starter for any connections!!!!!!

If you connect from the accessory post/stud on the back of the ignition switch to the coil, yes you will have 3 primary wires to the coil. (And one secondary cable out the center of the coil tower to the center of the distributor cap)
Two to the + side of the coil. (One you made and one from the factory wiring.)
One to the - side of the coil. To the distributor or to the points

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Discussion Starter #10 (Edited)
the distributer wire does not connect to the pos side of the coil
I have attached the wiring diagram for the MSD distributor and MSD coil. You will see what I am talking about. This is where I am assuming I would have 3 wires on the positive side... based on @Action idea. I don’t have a relay... just the distributor and coil.

Let me know if I am missing something before I try this :)
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the distributer wire does not connect to the pos side of the coil
Of course it does not.
And isn;t what I posted
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A relay is an electrical switch.
The most common use of an electrical switch is to turn on and off high current circuits

Unless I am mistaken the MSD coil does not require high current, So instead of using a relay controlled by the ignition switch, just use the ignition switch.
The thing to know would be how much current the coil requires. If less than say 10 amps, eliminate the relay and run the wire from the ignition switch to the coil.
You will still need two wires from the vehicle to the coil. 1 from the ignition switch for engine running. And one from the starter relay for engine cranking.

How the coil + goes to the distributor is a MSD thing that I do not understand. But then again I would never use a MSD system or distributor. Which is a far different topic.

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Discussion Starter #15
Guys thanks for the additional information and most importantly the education. It’s funny, just when I feel confident I know how all works I get reminded how much more I have to learn. It’s great to have this forum and you guys are great! @Action I did test the post on the back of the ignition switch and I get 11 volts, it’s better than 8, so I am wondering if I am losing voltage somewhere else. I will do more research on the MSD gear; @redrag the YouTube video was very educational. Will update you guys on how this comes togethe.
 

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The difference is called voltage drop.
And you have to compare it to battery voltage. What is the battery voltage, when the terminal is 11 volts?

And 11 may be good enough for the MSD system. However it might be good for the electrical system/battery to find out -
Do you have a bad or inaccurate test voltmeter
Excessive resistance in the system
Or something drawing power that should be off


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Discussion Starter #19
Hi @Action and all, once I had the wire connected to the back of the ignition switch there was 11.8 volts. So I hooked it to the positive terminal on my coil and the car started and remains running. I set the timing to 6 degrees before TDC and she is idling nicely. I still need to hook up the vacuum advance to the distributor but it looks like this will work just fine. Thanks for all the help @Action, @Dominick 1 and @redrag.
 
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