installiing pertronix ignitor

[cacockrum]

I'm installing a Pertronix system and Flame Thrower coil as part of the rebuild on my '66 convertible. Since I had the dash and wiring harnesses out, I decided to add a wire in parallel to the resistance wire along with a switch which will allow me to get either 6 or 12 volts to the coil in case I ever wanted to convert back to the stock set up. Other than that, I was able to preserve all of the original wiring except for the two wires from the Pertronix system to the coil. The small switch is contained in the harness behind the right side of the dash, so it's not visible unless I stand on my head, but still accessible enough to change if I want to.

I'm also putting an electric choke in the M series tri-power set up I'm installing, rather than route a heat tube from the right exhaust manifold to the left side of the center carburetor. Since I only want power going to the choke when the ignition switch is in the ON position, I plan to tap into the wire going to the coil. I want to install a fuse to protect against a short in the choke. Sooo my question is --- should I place the fuse between the coil and the choke, or can I put it between the starter relay and the coil? A related question is --- why is there no fuse between the ignition switch and the coil? Is this because the coil will never short out to the point where the wiring harness is damaged, or is there some reason why a fuse cannot be used in this circuit?

[jtschug]

You don't need a fuse between components unless you are down-gauging the wire from one component to the next. The fuse is sized so that the smallest wire in the circuit will not overheat at the full current the fuse allows (i.e. 15 amps for a 15 amp fuse). You can find tables for the maximum current rating for each wire gauge size. Usually engineers have some safety factor in there as well, so the fuse is smaller than the wire could theoretically allow (unless you are working on a Jaguar :-). Also the fuse can be placed anywhere in the circuit and perform the function, so it is most convenient to put them all in one place. In the case of the ignition switch, I think the fuse is between the battery and the switch. I do not think there are fuses for the power coming out of the starter solenoid, so if you power the electric choke off that, you may need a fuse in that wire somewhere for complete safety. I guess Ford decided they did not need fuses for the coil and starter because these components "fail safe" meaning when they fail it is an open circuit, not a short.

[RedBird64]

I agree with the above. No fuse is needed as the components themselves have such tiny windings they will open during a short.

[scumdog]

Jetbrd66... I have the exact same story, so much so initially I had to back to make sure I did not write the post. At this point I am going to stop focusing on carb and timing adjustments and begin looking at my petronix setup, I have a feeling this is going to be what's plagued me for the last 9 months and not my fueling system.

I was lucky, I figured out (suspected!) early on it was a lack of full voltage to the coil.

I ended up using the factory resistor wire to energize a relay hidden behind the headlight apron (?) near the windscreen bag, you can't see it unless you 'stand on your head''.
This relay sends a full 12V to the coil which is a 12V coil I replaced the existing one with since I didn't know its history.

Prior to that I had plug-fouling when doing slow cruising, now no problem at all.

[sleeper bird]

ok so this is being brought back from the dead again.iv got an ignitor 1 and a flamethrower coil.When i turn the key to the on position i get aprox 6 volts.iv not checked it running but will do so when i head back to my shop tomorrow.Iv read so many threads about this i think iv confused myself so running the coil should be getting 12 volts? iv got a 66

[64ZCODE]

12 volts to the coil, yes. Pertronix sells a power relay that provides the full 12 volts to the + coil terminal when the ignition is "on".

[sleeper bird]

12 volts to the coil, yes. Pertronix sells a power relay that provides the full 12 volts to the + coil terminal when the ignition is "on".

so the coil should be getting 12v at all times?

[Terry64HT]

If you have a Flamethrower coil it should have 12v all the time. Easiest place to get it is tap into the green/red stripe wire on your voltage regulator, it's switched 12v. You can hide it with the wires already going from the driver's side fender to the engine.
Pretty simple.
Terry
64HT

[sleeper bird]

If you have a Flamethrower coil it should have 12v all the time. Easiest place to get it is tap into the green/red stripe wire on your voltage regulator, it's switched 12v. You can hide it with the wires already going from the driver's side fender to the engine.
Pretty simple.
Terry
64HT

Thanks Terry

[sleeper bird]

so does the original switched wire brown in my case get abandoned?or does it stay connected to the positive side of the coil.

[Tbirdgul]

Sleeper it’s, Yes, I believe you can disconnect and cap it off. In the electrical diagram for my 64, the red/green and green/red wire merge at the ignition switch, I’m assuming your brown wire has the resistor inline, so you no longer need it connected at the coil.

Terry, I did what you said and installed a relay using the green/red as the trigger and wiring a wire to the battery fuse block. I have a fuse block next to my battery. Car started right up after I installed the Pertronix III. Stock coil. Cheers, Tony

[sleeper bird]

i was not thinking that the 12v coil wire drew that much amperage to need a relay but i guess i was wrong.i was going to go direct from the red/green wire at the voltage regulator straight to the coil.

[Tbirdgul]

I can’t speak for 66 wiring colors, but my 64 has green/red coming for the S terminal of the alternator regulator. My red/green wire also has a pink resistance wire from the ignition switch to my coil but I disconnected it from the coil once I connected the green/red from the regulator.

[Terry64HT]

I assume from the last 2 posts that the 12v switched at the voltage regulator is a green with red stripe wire on a 64 and the opposite for 66. If that's the case, it confuses things since red with a green stripe is the wire color from the ignition switch to the coil (with the pink resistor wire in the middle) on a 64. In any event, tapping into the wire on the S terminal of the regulator to attach to the coil is the way to go. Triggering a relay is purely a matter of choice (but I do love relays).
Terry
64HT

[sleeper bird]

ill see if i can get a picture,the cars at my shop.i noticed there was a green wire with a red stripe on my 66 coming from the regulator.Ill confirm if its getting 12v tomorrow.