Resistor wire

[RandyP63]

Hi all, I am new to the site, and I am impressed with the information available, especially schematics.

I have a 1970 F-100 Ranger SWB, I just purchased it and I am trying to clean up a wiring mess from the previous owner. I started with a NOS Ford under dash harness, now I am working in the engine bay, the PO butchered the harness that runs down the passenger side fender so bad he had another fuse panel on the floor for an HEI distributor. I sold the engine with the HEI and I replaced it with a 302 and a Pertronix Ignitor, since the harness is new and the distributor is also, do I need to install a resistor inline for the distributor? It is a Pertronix with a pertronix coil. Thank you.

[fastEdsel]

I just kept the ceramic resistor on the firewall with my Pertonix coil and igniter and it works just fine. I wired from ignition switch to resistor to "+" side on the coil and so far no worries. Hope this helps.

[69Ford]

I run a full 12 volts to my pertronix runs great. The reason for the resister wire, ballast resister, or resistor coil was to keep the voltage down so the points wouldn't burn up. Ford actually bypassed the resister wire while the starter solenoid is engaged for better startup. g

[RandyP63]

Thanks for the replies, on my out to the garage to hopefully complete it today. Off to get the ballast resistor.

[Ranchero50]

Wait a minute. What 69 ford said is correct but can use some expansion. When you turn the ignition key to on with the engine not running and the points happen to be closed the coil is charging. The coil has very low resistance so it gets hot quickly. The load resistor's purpose is to share that resistance and keep the coil / points from failing.

With the pertronix and most other electronic ignitions the coil only charges on the hall effect pick's up the signal that the engine is turning over. What do the pertronix instructions recommend? Ford laced @ 6' of resistor wire in the dash harness behind the instrument cluster so you already have a load resistor in circuit. If pertronix doesn't want one you will need to modify your harness.

Personally I'd unwrap the harness at the key switch and where the ignition leads go through the firewall and solder a jumper between those points and leave the resistor wire in place. That way the work will be hidden behind the dash and function correctly. If you are clever about it you could leave a loop exposed and just cut it when your pertronix dies in the middle of nowhere and you need to install a set of points to get home.

[69Ford]

My Diagram.jpg

Here's my diagram of how our ignition is wired. Very simple in the diagram the start and run are reversed on the ignition switch my mistake.

[sargentrs]

When I swapped in a Duraspark ignition in my '70, I tapped into the red/yellow wire right behind the switch with a clamp on connector that has a spade terminal on it. It shares the pin with the resistor wire. I know it's not professionally done but it was just a trial set up. Worked so good I never got around to rewiring it. I used this diagram and original harnesses from another member.

[RandyP63]

Holy cow, thanks for the diagram. I will use the picture to wire mine the same way tomorrow. I stepped away from the electrical today to prep the engine and trans.for install. Thanks again.

[sargentrs]

More diagrams here that may be closer to your actual application. http://www.fordification.com/forum/view ... =8&t=48178

[RandyP63]

Okay, I'm usually not this dumb, but I went to tap into the wire on the ignition switch (bypassing resistor wire) for the positive side of the pertronix coil, looking at the diagrams and referring to the schematics on the Website there are a few things that are confusing me. On my ignition switch, the pink wire shares a post with a blue wire, not red/green. I was going to tap into the red green for the positive side of the coil. When I look at the color chart on the site it says the blue wire feeds Turn signal flasher.

There is no red/green wire on the switch, and according to my schematic, there should be.

[sargentrs]

One of those wires on the back of the ignition switch is full 12v with key in "on" position. Just grab a tester and find out which one. Color codes are known to vary year to year, model to model and you never know what some PO may have done. According to the master wiring diagram, the pink resistor wire shares a pin with a red/green wire which is full 12v with switch on. That's the one I used and tested it for full 12v before I tapped into it. As you can see in my photo, it's not the red/green color detailed in the diagram, more like red/yellow. Why not? One may never know.

[RandyP63]

Well, after 5 months I finally did a test on my electrical system.....it actually works. One question, I found a key on 12V source for the coil, the resistor wire is not being used anymore, but I have a set of points in the glove box just in case. My question is; how hot should the resistor wire get? In the run position it gets pretty warm. I never had a resistor wire in any of my other Fords, just curious. Thanks to everyone for their help.