1973 ignition wiring

Hey all, i recently came into possesion of a 73 bronco that was used as a woods buggy. The previous owner stripped it down to basically nothing with intensions to upgrade suspension, roll cage, and custom body panels etc. Anyway, he stripped out all the wiring, left a mess and lost interest lol.

In still pretty new to working on this stuff but managed to rewire the basics of the ignition system using a couple different schematics and finally had it started for the first time the other day. (Put new coil, points/condensor, sylenoid on it which helped rule out lots of problems). I think all is pretty good, its a bare bones wiring job ommitting 80% of what's on the schematics and leaving only basics to keep the engine running.

I did notice the wires going to the coil and key feel a bit warm...and im not certain my voltage reg is working.

Wondering if anybody has a good schemaic for the iginition system.... or could sketch out the basics of what i need to keep it running (im hoping i have it right...).

From what i can tell there is bacically only about 8 or so wires needed. I dont know how to test the voltage reg for proper operation. Also, i read that there should be a resistor wire going to the coil (which i didn't do). The fact the wires are getting warm has me a bit nervous.

Hi Wesside.., welcome..!!   

You likely need the older style "ballast resistor"  that reduces the voltage to +-6 V to the coil.

16/16A is the resistor wire.  That's where the ballast res. would go.

Can be tricky to follow these wires(lines). You could print these & color ea. wire needed

with colored pencil so as to follow(track it)

Wow, thanks Bob, quick reply! Those are much better than the schematics i pulled off bronco graveyard.

I ran 16 guage to all the componets. A section of the original wire harness was in tack from the altinator to the voltage reg, but thats it. I bypassed most other stuff and as stated can get it to start/idle fine but was nervous i used under guage wire or has something wired incorrect when i felt warm wires...i did have a battery charger on the battery when i noticed. And was basically holding the key on/off/start for several minutes straight while tweaking the carb...

What guage wire would u consider ideal?

I think its getting a full 12+ volts to the coil atm. Which will birn it out pretty quick expect.

I seen a puff of smoke from the voltage reg the very first time i tried to start it.... thought it might have been mud in it. Only did it the once then no more

"What guage wire would u consider ideal?"

------ Seabronc can serve you better as to wire gage..., he's our wiring expert on this site &

        will likely view your posts if not already.

Droping voltage to 6v is easier on the points.

The newer (pertronix,etc.) electronic ignitions run on a full 12v because there's no points.

Auto parts have the ballast resisters. It's just a porcelain block with a coil on it.

Yo wesside 73,

Sorry about the PMs!!!

I tried sending them to a spammer that posted **** pics. I sent them, but somehow they went to you. Probably due to recent vision problems or slight lag.

I didn't notice that they went to you until your responded.

I am a **** ...

Al

All good. I thought it might be a test for the new guy lol. I seen you were a moderator and assumed there was likely a good reason.

I'm certinly not posting **** lol, maybe a pic of a stripped down old girl ( my rig without body panels haha).

Yo wesside 73,

Thanks!!!

I never PMed a spammer before, but this one appeared intent on dropping in more **** and did not appear to be a bot. Never did it before and sorry I did and sent it to you by mistake.

BE well!

I'll try to get back to you by tomorrow.  For now, you should be using automotive wire not the standard stuff from some place like Home Depot.   As Bob advised, if that is an older distributor and coil you need either the resistive wire or a ballast resistor in line with the 12V line to the coil'

Attached is a Duraspark ignition wiring diagram.  You will see the resistive wire in the top right of the diagram.  So in that line you need resistive wire or a ballast resistor to keep the current down in the coil.

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It's the older style points/coil. I'll need the resistor/traitor wire then, have to hit the auto parts store and try to scoop one up.

I might price out a voltage reg the same time. I havent had a change to chase the wires in the one i have, but think i have one going to the coil and one back to the battery (cant remember off hand)

Putting voltmeter probes on the + side of the coil, with key on, will tell you the voltage.

Point being, you may still have the "resistor wire" in place. (It's a fatter looking wire)

If you did, in fact, run a replacement wire there..., an auto parts ballist resistor may be easier

& cheaper to install just prior to the + side of the coil.  (The coils are 12v)

If not mistaken.., these ignitions "start" on 12v ----- "run" on 6v.

It's possible a resistor or resistor wire won't take the heat out.

A test would be to turn the key to "on" in the run position (eng. NOT running).., wait a bit & see if

the wiring heats up.

If so.., there's a way to do this using a 30 amp relay.

If you notice the wiring in the diagram, the "Start" position of the ignition switch runs 12V directly to the coil but when it is in "Run" the connection to the coil is through the ballast resistor or the resistive wire.  The resistive wire is pink and is usually folded back on itself a couple of times.  As far as other wires are concerned, the size depends on the current drawn by the load and the length of the run.  Here is a good source to aid in figuring out what is acceptable when wiring with automotive wire.

https://www.tessco.com/yts/industry/products/itm/automotive/get_wired.html

Just so you know, the design of automotive wire uses smaller and more strands to make it up, which makes it less brittle and susceptible to breaking from flexing.  

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This may help you as well.  They have just the eng. & alternator wiring kits.

www.broncograveyard.com 

http://shop.broncograveyard.com/Harness-Alternator-Engine/products/1166/

Its firing up and working great now guys. The resistor wire was actually still there, but in poor shape (chafed throgh in one spot) so ill likely repace it with the resistor.

Looking at the way i have it wired vs the scematice, i have a bit of confusion about the voltage regulator and its role... anybody able to quickly give the basic operating principal or let me know if im on point? Altinator produces d/c to Volt Reg, it charges the battery but when battery is full directs power to aux/coil?

The voltage regulator does just what is called, it keeps the voltage from the alternator close to 12V, actually around 13.5V at the battery.   The battery's function is simply to start the engine.  Once the engine is running the alternator should supply the current demands of topping off the battery and supplying the electrical loads like lights, radio, small motors like door and tailgate windows if there, anything that requires electricity to operate.   If you are adding large loads like off road lights, stereos, etc. you may need to increase the size of the alternator.  The alternator only puts out enough current to supply the current demand, so if the demand is 10 amps then that is all it puts out.  Older alternators had a maximum continuous output of around 50 to 65 amps which was more than enough for factory installed equipment.  If however, the demand is 75 Amps then a 65 Amp alternator would not be able to handle the load and the difference would have to come from the battery.  that of course, would end up discharging the battery, which is why you need to consider a larger alternator if adding a bunch of electrical gadgets to a vehicle.  If running with factory equipment the existing alternator is plenty large enough to handle the load.

Glad to hear that you found the resistive wire.  You could cut the wire at the rub through, splice it using solder, and then seal with shrink tubing.

Good luck with your project,

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