[bob d]

I'm switching back to points from pertronix. I there one or two resistance wires going to the coil. I found a blue wire not connected taped up near the coil. It's not the oil sending wire. Thanks.

[steve25]

I forget the color of the original wire.

Hook that blue wire up to your coil and measure the voltage reading you get.

The correct wire will have full battery voltage on it when cranking and then only 9 volts in the normal run position.

[Goatracer1]

The resistance wire should be very noticeable. It is white-ish and has a braided insulation. What car?

[bob d]

IT's a 1965 gto. there is a black wire with a pink stripe on the coil now. is that the resistance wire?

[Schurkey]

Originally Posted by steve25

I forget the color of the original wire.

Often fabric-covered and light-colored if it's not stained with grease and dreck. But I haven't messed with points in thirty years. Couldn't be bothered when superior systems are readily available at low cost, and as near as a well-stocked Treasure Yard. God bless the HEI.

The GM service manual will have the wiring diagram and wire colors.

Originally Posted by steve25

Hook that blue wire up to your coil and measure the voltage reading you get.

The correct wire will have full battery voltage on it when cranking

Keeping in mind that battery voltage is reduced when the starter motor is engaged. The actual measured voltage at the coil is likely to be as much as one volt lower than the battery voltage due to resistance in the ancient vehicle wiring and connections.

Originally Posted by steve25

and then only 9 volts in the normal run position.

...with the engine running. With the engine NOT running, if the points are closed, the voltage may be lower-yet; and if the points are open, it'd be full battery voltage.

[Lemans64]

Black with pink is the 12 volt wire that goes to coil +, but back inside the harness there is a splice point with a White - orange -purple resistance wire that starts at
the firewall plug in terminal position 1, black pink is pin 7 on same plug. 7 is 2 down and on other side of plug.
https://www.oldcarmanualproject.com/...ing/index.html
use tempest right side of wiring diagrams

[lust4speed]

Might not be a bad idea to mention that if the engine isn't running, then the points must be closed while the key is in the run position to check the resistance wire. Open points will be an open circuit and there won't be any load to allow the resistance wire to work. Probably easier to just wait until the car is running and then check voltage and see if it is somewhere in the range of six to nine volts. Your volt meter and the condition of the resistance wire will affect the reading. Basically you're good to go as long as you don't see a higher voltage reading.

[Kenth]

With ignition "on" points closed you should see 5 to 7 volt checking V2 on diagram.

With engine running you should see about 11 volts checking V2.

[locomotivebreath]

Is it possible to make the resistor wire or add a resistor if he missing it and not the Mopar style unit ?

[Cliff R]

Good idea to switch back to points, IMHO. I've had so much trouble with Pertronix in recent years (I could put up a couple dozen pages here detailing BAD experiences with them) that using good USA made points are the only thing I'll try these days in the older points type distributors.

Anyhow, you need an OEM resistor wire from the key switch and an ignition bypass wire for full voltage when cranking. If not using the original full length bypass wire you'll have to install a resistor in line to the coil. I can't remember the ohm value of the ones we used to use but I'm sure someone on here can chime in witht the correct value to reduce the voltage to the correct values when running points.......

[HWYSTR455]

Originally Posted by locomotivebreath

Is it possible to make the resistor wire or add a resistor if he missing it and not the Mopar style unit ?

In the past, I've replaced the resistor wire in my cars, for a number of reasons. One big factor is that over time, the resistor wire looses it's value, and can provide more voltage than desired.

Another is HEI and aftermarket ignitions usually require a full 12 volts.

If switching back to a situation where you need resistance, just use an external resistor, like the Mopar ones. They are heat-sink'd, and last much longer than the old burned up wires.


.

[HWYSTR455]

Remove the wire/terminal from the engine harness, and save it for later if you want. Use a new wire and a new packard terminal:

https://www.summitracing.com/parts/a...SABEgKVU_D_BwE

Add an external regulator and boom. Done.

https://www.summitracing.com/parts/s...SABEgLNMfD_BwE

https://www.summitracing.com/parts/a...SABEgLTDPD_BwE

.

[T.Weber]

Or you can use a GM style resistor.

1.8 Ohm (blue stripe) here https://www.ebay.com/itm/284418712712

.3 Ohm (black dot) here https://www.ebay.com/itm/261661344559

[bob d]

Thanks for the wiring diagram. So if the resistance wire is spliced to the black and pink wire you only need the black and pink wire on the + of the coil and the distributor wire on the - side correct. The gto ran good before with the points.

[HWYSTR455]

Wow, those eGay ones are not cheap.

The Standard one is very similar, and think they may have made them for GM?

They aren't correct, but wouldn't be anyway if you are replacing a resistor wire car.

Interesting on the values, didn't realize there were 2 diff ones. Is the .3 ohm one for 6v apps?


.

[Kenth]

The "Standard" (SMP) RU10 resistor is 1.77-1.87 Ohms @ 70°-80° F and is what is recommended for GM points ignition resistor wire replacement.

Nota bene: This is when used with a coil with 1.8-2.0 Ohms primary winding (over + and - terminals).

[Lemans64]

Originally Posted by bob d

Thanks for the wiring diagram. So if the resistance wire is spliced to the black and pink wire you only need the black and pink wire on the + of the coil and the distributor wire on the - side correct. The gto ran good before with the points.

Correct, but check voltage after to make sure resistor wire is still there. Should be approx 9 volts car running, not full battery voltage.

[Formulas]

Isnt pertronix supposed to use full voltage,? IE your black n pink wire not giving best results?

i never ran pertronix just what i may have gathered

[HWYSTR455]

I picked the RU-13 because of the bracket, believe it might be the same value as the RU-10? Both appear to be listed for similar applications.

I've seen the ones where the bolt goes thru the ceramic crack and fall off, at least that was the case on my Mopar. If you leave it loose, the screw falls out.

.

[67drake]

Originally Posted by Formulas

Isnt pertronix supposed to use full voltage,? IE your black n pink wire not giving best results?

i never ran pertronix just what i may have gathered

No expert here either, but I THINK the Pertronix first generation (or whatever they call it) uses the resistor and stock coil still. The Pertronix II and III use 12 volts and different coil.
I too am switching over to points from a first gen Pertronix. Waiting to get my distributor back from the rebuilder.