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Old 08-03-2019, 12:01 PM   #51
dmjlambert
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Sorry, I should have pointed out, an exception to the diagram colors matching the wire colors is 20W/OR/PPL, after all these years on your truck it has faded to be just a plain white cloth covered wire. That is the resistor wire that powers a standard points distributor/coil. That is the one you replace with a pink wire to power HEI. You can buy a ready-to-use wire if you want, and install it like this> http://67-72chevytrucks.com/vboard/s...d.php?t=708975
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Old 08-03-2019, 12:08 PM   #52
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Re: 68 C10 Yellow wire from firewall to starter/coil.

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Originally Posted by dmjlambert View Post
Sorry, I should have pointed out, an exception to the diagram colors matching the wire colors is 20W/OR/PPL, after all these years on your truck it has faded to be just a plain white cloth covered wire. That is the resistor wire that powers a standard points distributor/coil. That is the one you replace with a pink wire to power HEI. You can buy a ready-to-use wire if you want, and install it like this> http://67-72chevytrucks.com/vboard/s...d.php?t=708975
Awesome, thanks for the help and No Problem... Trust me! just glad to have the advice from this awesome site.

So I think this is the right one, drew an arrow this time. Another friend agrees with me but he works on Grand Nationals, not these trucks...
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Old 08-03-2019, 12:09 PM   #53
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Re: 68 C10 Yellow wire from firewall to starter/coil.

OK, it looks like somebody has already changed your white cloth covered wire to a pink HEI power wire same as I did in this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=708975

Use that pink wire.
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Good picture, sorry about the confusion. You no longer have the 20W/OR/PPL wire that would normally fade until it becomes a white cloth covered wire like mine did. It was a resistor wire that powered the old points distributor. That newer pink wire is not a resistor wire, and provides the full 12V power to the HEI distributor.
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Old 08-03-2019, 12:14 PM   #54
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Re: 68 C10 Yellow wire from firewall to starter/coil.

If you had a points distributor with that non-resistor pink wire, I recommend checking where it goes. If it goes to a ballast resistor and from the resistor went to the coil, then you won't need that ballast resistor any more.
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Old 08-03-2019, 12:20 PM   #55
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Re: 68 C10 Yellow wire from firewall to starter/coil.

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If you had a points distributor with that non-resistor pink wire, I recommend checking where it goes. If it goes to a ballast resistor and from the resistor went to the coil, then you won't need that ballast resistor any more.
Yep, agreed, that part I am on top of, I am going to use a but connector to rob that wire out of the firewall and take it over to the new distributor. If they did change it they left the resistance wire on that because I have a yellow to the Coil today. That will come off, there is a 2nd wire on the hot side of the coil that goes through the grommet hole on the FW, so I assume thats my aftermarket Tach but I can simply check it for voltage in the run position to make sure.
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Old 08-03-2019, 12:31 PM   #56
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Re: 68 C10 Yellow wire from firewall to starter/coil.

You have to check the voltage while it is actually hooked up to the coil or HEI distributor, and check the voltage at the coil or distributor, because if a resistor wire has no load it will read 12V. When you put a load on it, it drops in voltage. Or just follow the wire and verify where it goes. For HEI you don't need it to go to the starter. That starter connection and yellow wire from starter to coil was only to provide a full 12V during start, to give the coil extra high spark voltage to make sure the engine would start. Once started, the coil just received a reduced voltage from the resistor wire or ballast resistor, and that makes the points last longer.
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Old 08-03-2019, 12:47 PM   #57
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Re: 68 C10 Yellow wire from firewall to starter/coil.

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Originally Posted by dmjlambert View Post
You have to check the voltage while it is actually hooked up to the coil or HEI distributor, and check the voltage at the coil or distributor, because if a resistor wire has no load it will read 12V. When you put a load on it, it drops in voltage. Or just follow the wire and verify where it goes. For HEI you don't need it to go to the starter. That starter connection and yellow wire from starter to coil was only to provide a full 12V during start, to give the coil extra high spark voltage to make sure the engine would start. Once started, the coil just received a reduced voltage from the resistor wire or ballast resistor, and that makes the points last longer.
Awesome, thanks! hopefully we will have fire tonight or find out we had a short all along
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Old 08-03-2019, 11:07 PM   #58
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Thanks again for all the help got her started up today. Going to get some fresh gas in the a.m. along with some seafoam maybe some oil treatment just to make sure everything is good.

I did get all freaked out cuz it was smoking so much. until tonight when I remembered that when we change the plugs about a month ago when we started all this we had fog the cylinders LOL
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Old 10-17-2019, 04:05 PM   #59
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Re: 68 C10 Yellow wire from firewall to starter/coil.

What a great thread this is! I recently bought a Pertronix system to replace my points.

I have a 1968 C-20 with a 327 in it.

Just to summarize or me and make sure I have this right, here is my plan. I will not be doing this for several weeks as I sent my quadrajet to the local guru to rebuild for me and I don't want to add any variables.

I can remove the yellow wire from the coil and leave it unattached and leave the wire on the starter. I can put this back on if I need to return to points.

I can take the firewall connector apart and remove the cloth covered wire and just leave it aside in case I need to return to points.

Use a new Packard 65 connector and 12 gauge wire to go from firewall connector to the coil.

That's it, right?



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Old 10-18-2019, 02:47 AM   #60
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Quote:
Originally Posted by Happy_dan View Post
What a great thread this is! I recently bought a Pertronix system to replace my points.

I have a 1968 C-20 with a 327 in it.

Just to summarize or me and make sure I have this right, here is my plan. I will not be doing this for several weeks as I sent my quadrajet to the local guru to rebuild for me and I don't want to add any variables.

I can remove the yellow wire from the coil and leave it unattached and leave the wire on the starter. I can put this back on if I need to return to points.

I can take the firewall connector apart and remove the cloth covered wire and just leave it aside in case I need to return to points.

Use a new Packard 65 connector and 12 gauge wire to go from firewall connector to the coil.

That's it, right?



Dan, if you want it reversible, you don't need to mess with the contact on the Bulkhead Connector. Just leave the Wht/Orange/Purple 20 cloth-covered wire alone. Tape off its other ends, the two Yellow 20 terminals [one at the solenoid and one at the coil] and wrap them back in the bundle. Run a fresh 10- or 12-gauge wire from the Ignition Unfused terminal in the Fuse Block to the Red [Positive] terminal on the Flamethrower coil.

[When your Pertronix ignition burns out, you can easily go back to points by stripping out your two Yellow leads and reattaching them, Replacing the coil, reinstalling the Points breaker plate inside the distributor and regapping plugs back to .035.]

Adjust the gaps on your spark plugs out to .045 for high energy ignition.

If you have the Pertronix One [not II or III] be sure to keep your key in the Off position when the engine's not running. Leaving the key On without running can burn out the module inside the distributor. This is not a problem with the Ignitor II or III.
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Old 10-18-2019, 12:03 PM   #61
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Thank you much! I have the Pertronix III module and coil. I think I will do it your way to make it easier to go back to stock with no evidence left.

Appreciate the advice for sure!
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Old 10-18-2019, 02:50 PM   #62
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Re: 68 C10 Yellow wire from firewall to starter/coil.

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Originally Posted by Happy_dan View Post
Thank you much! I have the Pertronix III module and coil. I think I will do it your way to make it easier to go back to stock with no evidence left.

Appreciate the advice for sure!
A buddy of mine has a P-III on the 429 in his '72 F250. He was unable to use his tach because of the multi-spark-discharge interfering with the signal. He called Pertronix, and the tech rep said to get a P-II.
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Old 10-19-2019, 04:48 PM   #63
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Re: 68 C10 Yellow wire from firewall to starter/coil.

I don't have a tach in my truck. I ddid read there are issues with tachs and p-iii

I have another question. Never saw these types of connectors before.

Can I plug a connector into the end of this that is open and use it for the coil? It would be two devices. The pink looks like it goes to the tranny kick down.

Or should I use the spot next to it and what kind of connector do I put on there?

Finally, what size are the glass fuses. I don't have any of those and want to get some spares but not sure on the size. I see 1/4 x 1/4, 35MM etc.


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Old 10-19-2019, 05:25 PM   #64
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Re: 68 C10 Yellow wire from firewall to starter/coil.

That looks like a piggy back connector, it allows you to plug in a device and you will still have an available place to plug in something else. It is a convenience.
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Old 10-19-2019, 06:09 PM   #65
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Re: 68 C10 Yellow wire from firewall to starter/coil.

What I can see is the pink wire goes to the kick down on the carb bracket. That is the pink wire, so yes, I agree. It looks like it is a "y" for lack of a better term connector so I can plug a connector into that and the other end on the coil and be good go. I am looking for what the connector is that plugs into that so I can get one and be ready.

This is all three weeks or so out as I wait to get the carb back and take care of that first. I don't want to add any variables in case I have issues still.
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Old 10-19-2019, 06:27 PM   #66
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Would this plug right into that connector?
Seems easy enough. Plug this in, run through the firewall, connect to coil.

https://www.amazon.com/dp/B001RPWVUY...NsaWNrPXRydWU=


EDIT: Nope, seems like the same end. Need the other half.
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Old 10-19-2019, 06:35 PM   #67
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Re: 68 C10 Yellow wire from firewall to starter/coil.

The connector is called a Packard 56 connector.

This is what they look like, and example for sale listing. I have not bought from this particular vendor before, but I have bought Packard 56 connectors on eBay.

https://www.ebay.com/itm/381536497305
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Old 10-19-2019, 06:37 PM   #68
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Hmm, I have the crimp on part on the left (just the metal part). I bought them when I was going to use the bulkhead connector. I need the right side part of that if the left is what is on the truck. Didn't realize it was all packard 56.

Found this on Amazon.

https://www.amazon.com/Delphi-Metri-...524712&sr=8-15
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Old 10-19-2019, 11:50 PM   #69
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Re: 68 C10 Yellow wire from firewall to starter/coil.

NAPA has Packard connectors. Tap into the other blade in IGN UNFUSED if it's clear.
The connector in your pic [Dan] is specific to the BATT+ terminal of a GM HEI. It has a little ''Mohawk'' ridge to prevent its use elsewhere.

dmjlambert's pic has the right stuff.

Fuse size is roughly 1/4'' x 1''. Auto parts store should still carry them or Ace Hardware.
I believe they were called AGC type.
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Old 10-21-2019, 01:10 PM   #70
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Re: 68 C10 Yellow wire from firewall to starter/coil.

Perfect! Thank you again! Very helpful to myself who is lacking in experience with the classics but eager to learn.
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