Ballast or Resistor wire, 72 6 cyl 250?

[72SB]

Is there a resistor wire or ballast resistor for stock points dizzy, 250 6 cyl?

I just have the yellow wire on coil, not seeing another

Putting on a Pertronix kit

[Accelo]

yes, if it had points it has a resistor in the circuit.

[72SB]

and that wire or resistor block would be where??

not seeing a white cloth covered resistance wire or block on firewall

[geezer#99]

Follow the yellow wire back into the wrapped wiring.
The resistance wire will be spliced into the yellow wire.

[kwmech]

It's hard to believe how many times a week we answer this question

[72SB]

my 67 camaro had both the white resistance wire and separate yellow terminating on the same spade connector to + coil...this C10 just has the yellow wire ...which is why I ask the ?,

will pull back tape on wire loom to see if it transitions to white, thanks geezer

If so I will run a new 10 gauge from IGN to + coil and just tape yellow back into loom if in fact the yellow wire merges to white resistance. Yes I know I can just cut off at the white resistance part and splice in stranded from there, prefer running new dedicated

[geezer#99]

Seems every motor is different with regards to the length of the resistor wire.
Some terminate at the coil, some a foot away in the wrap.

I’ve done the same and just taped the existing wire up in case Ineeded to put the points distributor back in when the pertronix quit working. They aren’t bullet proof.

[MikeB]

Originally Posted by kwmech

It's hard to believe how many times a week we answer this question

Hmmm, I have to say this is the first time I've heard it, and I typically read electrical posts. Also, I don't like to criticize members for asking questions instead of searching. New answers may offer additional insight and information.

I was once on a dirt bike forum where their rules were "search before asking a question". My comment to the moderators was, "Why even have a forum if questions are discouraged?" Just change it to a read-only database or tell people to simply google the subject. They seemed to be especially nasty with new members seeking help.

[RichardJ]

On the inline engine, the splice for the resistance wire to the yellow (usually yellow) wire is alongside the valve cover.

GM used a 14 gauge wire to feed the HEI. This 14 gauge wire has a very fat insulation, causing most people to think it is a larger gauge than 14.
99% of the wires in your vehicle are never moved and become very stiff with age and heat. I think GM realized this HEI wire needed to remain pliable for occasional timing adjustment.
On the old points distributor, the distributor wire would sometimes fail because of cracked insulation and frayed copper wire.

GM already has a 12 gauge wire from the ignition switch directly to the bulkhead connector.
Run a new wire from the bulkhead connector plug, directly to the HEI.

HEI distributors typically draw 2-3 Amps. A factory HEI with factory coil, less than 2 Amps.

Consult a wire Amperage Chart for 12 volts.
AutoReWire Chart http://www.autorewire.com/image/amps...art_436020.jpg

You need about 3 feet of wire from the bulkhead connector to the HEI. A 10 gauge wire at 12 volts will carry 150 Amps. Do you really think you need or want that?

[Rickysnickers]

Originally Posted by MikeB

Hmmm, I have to say this is the first time I've heard it, and I typically read electrical posts. Also, I don't like to criticize members for asking questions instead of searching. New answers may offer additional insight and information.

I was once on a dirt bike forum where their rules were "search before asking a question". My comment to the moderators was, "Why even have a forum if questions are discouraged?" Just change it to a read-only database or tell people to simply google the subject. They seemed to be especially nasty with new members seeking help.

I like this post!! Thank you for saying this.

[72SB]

Originally Posted by MikeB

Hmmm, I have to say this is the first time I've heard it, and I typically read electrical posts. Also, I don't like to criticize members for asking questions instead of searching. New answers may offer additional insight and information..

Yeah Mike, every forum has "that guy" who only post criticism vs any input to the answer of a ?

I searched, title only, resistor wire and didn't find answer but likely a search of entire thread likely would have turned up answer after reading a bibles worth of content

My ? was based on engine pics I had of the truck before taking delivery so I could not look directly myself

Now I have the truck and found it has a Pertronix kit. The only wires on + side of coil are the yellow on what I assume was the original spade and the red wire from Pertronix module

Traced yellow to rear of valve cover and still yellow, no splice there.

Pertronix are not happy with resisted voltage (8 IIRC of resistor wire)

2 harness from bulkhead connectors running to PS of motor have no white resistor wire nor yellow so will have to untape both to see if the yellow wire is spliced in somewhere. Tape on looms appears to be original so not seeing a initial splice spot

the 3 wire harness runs to a relay on firewall, top DS

colors:
black
blue
black/white stripe

the 6 wire harness colors running to PS engine:

Pink (big)
pink (small, this appears according to wiring diagram the wire that splices to yellow))
black/white stripe
Tan
green
purple

so at some point one of those color wires splices to yellow but none appear to be a cloth covered white resistor type wire.

Bulkhead plugs do not appear to have a repin "replaced" wire. No additional wire run from fuse block through firewall

So looking at engine bay wiring diagram (pic) it appears the yellow wire splices to pink/black (not specific on where). I have no pink black wire, just pink (smaller of the 2 pink wires) going to terminal 3 on bulkhead harness. KOEO the yellow wire reads 12.87 v at + coil side so the voltage is not being resisted

So did points dizzy on 72 trucks not have a white, or other color, resistance wire. If so what color is it and what pin on bulkhead connector did it originate?

[MikeB]

Just found something on my 69 that doesn't make sense. It's had a GM HEI since the mid-1990s. Can't remember how I wired it, but was just looking at the factory schematics and they don't make sense.

The "instrument panel" schematic shows a 12 gauge wire labeled "12P" connected to the ignition switch. I had written "ignition wire" on the drawing. But on the "engine compartment wiring" schematic there is no "12P", but instead it shows "20W/OR/PPL" (which I assume is a resistance wire) running from the bulkhead connector to coil positive terminal.

Connected to that same bulkhead connector terminal is a pink 12 gauge wire, which I assume is the mysterious "12P". (lower left in photo)

No big deal because I have >14 volts to the HEI (engine running), but I don't know what "12P" would have been used for, and why it's not shown in the engine compartment schematic.

I do have a new AAW wiring harness kit on the shelf, just waiting for me to get off my butt!

[RustyPile]

Originally Posted by MikeB

Just found something on my 69 that doesn't make sense. It's had a GM HEI since the mid-1990s. Can't remember how I wired it, but was just looking at the factory schematics and they don't make sense.

The "instrument panel" schematic shows a 12 gauge wire labeled "12P" connected to the ignition switch. I had written "ignition wire" on the drawing. But on the "engine compartment wiring" schematic there is no "12P", but instead it shows "20W/OR/PPL" (which I assume is a resistance wire) running from the bulkhead connector to coil positive terminal.

Connected to that same bulkhead connector terminal is a pink 12 gauge wire, which I assume is the mysterious "12P". (lower left in photo)

No big deal because I have >14 volts to the HEI (engine running), but I don't know what "12P" would have been used for, and why it's not shown in the engine compartment schematic.

I do have a new AAW wiring harness kit on the shelf, just waiting for me to get off my butt!

At the risk of being admonished, I'll offer this explanation. It makes perfect sense and there is no "mystery" involved.. Voltage is fed directly from the battery to the ignition switch through the red 12R wire.. When the switch is "ON", voltage is fed through that pink 12P wire from the switch to the fuse box. On the way to the fuse box, it splits and also 12P goes to the firewall connector block. On the engine side of the connector block, the 12P changes to the 20W/OR/PPL cloth covered resistor wire..

When installing an HEI, the most common modification is to remove the resistor wire and its accompanying "yellow wire" at the connector block and replace it with a 14 GA wire feeding directly to the HEI unit.

[MikeB]

Originally Posted by RustyPile

On the engine side of the connector block, the 12P changes to the 20W/OR/PPL cloth covered resistor wire..

That's the mystery! Look at my photo. There's a 12ga pink wire (or maybe faded red) on the same terminal as the resistance wire and it runs to my HEI.

Like I said it's been nearly 30 years since I did the conversion. I don't remember somehow attaching that wire to the terminal plug, but maybe I did.

Thanks for pointing out that the 12P wire feeds the IGN bus on the fuse panel. That's a real "duh" on my part. I need to change my notes on the schematic from "ignition wire" to "HEI and IGN bus".

[RichardJ]

>>is to remove the resistor wire and its accompanying "yellow wire" at the connector block<<

I'm not sure what connector block, but the yellow should be removed from the Starter Solenoid.

All of what RustyPile said is correct.

As for the White wire, I don't understand why people call it White. I think Dirty White is a better description. When new the color was White/Orange/Purple or 20W/OR/PPL.

This picture is from this forum. I can't take a picture of mine right now as my son-in-law is using my truck to haul cement blocks and pavers.

[RustyPile]

Originally Posted by MikeB

That's the mystery! Look at my photo. There's a 12ga pink wire (or maybe faded red) on the same terminal as the resistance wire and it runs to my HEI.

Like I said it's been nearly 30 years since I did the conversion. I don't remember somehow attaching that wire to the terminal plug, but maybe I did.

Thanks for pointing out that the 12P wire feeds the IGN bus on the fuse panel. That's a real "duh" on my part. I need to change my notes on the schematic from "ignition wire" to "HEI and IGN bus".

If that "mystery wire" connects to the same terminal with the resistor wire, it's a non-factory addition. Leaving the resistor wire in place is not a good idea. When the ignition is ON, this wire is "hot" with nowhere to go.. Having a "hot" wire wandering around in the harness is just asking for trouble.. Remember -- it's unfused (not protected)..

[RustyPile]

Originally Posted by RichardJ

>>is to remove the resistor wire and its accompanying "yellow wire" at the connector block<<

I'm not sure what connector block, but the yellow should be removed from the Starter Solenoid.

All of what RustyPile said is correct.

As for the White wire, I don't understand why people call it White. I think Dirty White is a better description. When new the color was White/Orange/Purple or 20W/OR/PPL.

This picture is from this forum. I can't take a picture of mine right now as my son-in-law is using my truck to haul cement blocks and pavers.

Maybe my East Texas vernacular is confusing you.. Let me rephrase.. The yellow wire is attached to the resistor wire somewhere along it's run between the firewall connector block (not to be confused with engine block) and the ignition coil. The other end of the yellow wire terminates at the starter solenoid.. Remove the resistor wire from the firewall connector and disconnect the yellow wire from the starter solenoid.. Unwrap the harness and remove this 2 wire "assembly" from the harness.

As for the color coding I used to identify the resistor wire, that code is taken directly from the GM factory wiring diagrams. As we all know, insulation colors on these old trucks fade considerably with age.. Some fade more than others..

[MikeB]

Originally Posted by RustyPile

If that "mystery wire" connects to the same terminal with the resistor wire, it's a non-factory addition. Leaving the resistor wire in place is not a good idea. When the ignition is ON, this wire is "hot" with nowhere to go.. Having a "hot" wire wandering around in the harness is just asking for trouble.. Remember -- it's unfused (not protected)..

I have to agree with you about the mystery wire. Heck, I must have added it because it was a bone stock truck with a 307 and points distributor when I bought it. I just don't remember doing it. And as an old electronics tech, I can't believe I would have left the resistance wire in place. Weird.

I'm not sure how the resistance wire is terminated because it's wrapped in a bundle. However, it's been that way for nearly 30 years. But if it does short to another wire or ground, at least its current will be limited.

I'm just amazed that I get 14 volts to the HEI through all the old wiring and connectors! Not that I trust it. Gotta get started on that AAW harness. Last one I installed (on a square body) had close to full battery voltage at the headlights.

[72SB]

Well on my 72 there is no white resistor wire coming out of any terminal on the bulkhead engine side. There is a yellow wire to + side of coil that apparently at some point within the wire loom is spliced. One diagram shows orange/black. My 72 wiring diagram book shows yellow being spliced (even says spliced) to a R/B (assume red/black) going to terminal 3 of bulkhead. #3 at the bulkhead is the smaller of the 2 pink wires.

I tested voltage with engine running at yellow wire, 13.8v, 12.6 with KOEO. In my case I have confirmed my Pertronix module is seeing 12v running so I am good. Unfortunately any wiring diagram does not correspond to my wire relative to what the yellow wire is spliced to. Short of un taping the entire harness to see WTF, I will move on to stuff that needs attention

I just got the truck and there are several "hack" hose routing, etc I need to clean up.

Things like just 1 bolt holding the truck bed had a nut/washer. Clear PO knew nothing and body shop did the usual hacks on assemble but the bones of the truck are good

[RichardJ]

72SB, you might consider using the wiring schematic found in the electrical section of this forum. Your wiring diagram shows the connector side of the engine harness plug. The pinout is swapped from the schematic that most people will be using on this forum. This schematic shows the wire side of the connector plug. Not the spade side.
You'll also notice the 20W/OR/PPL label on the resistor wire.

The dash side connector shows the mirror image of the engine harness connector. Connections are swapped left-to-right in the pinouts.