I have looked through many posts but have really come up empty handed so thats why I ask this question. I have a new TDHEI and the HEI kit from MAD and new wiring harnesses so I want to take care of the wiring while I have it out. I have seen a few theories but have picked 1 if someone can help. I know that I have to discard the ballast wire and yellow R wire ( I also have a mini-starter) I was wondering what wire I need to tie into to get the 12 volts during start and crank but not when the accessories is on. I will post pics when done. (1969 SBC) THANKS! (thanks 69427 for the help so far)

 

Easy way to wire an HEI--

Run a 10 gauge wire from inside the car "FUSE BLOCK" position "IGN UNFUSED" directly to the +BAT terminal on the HEI distributor.

The existing wires- just tape them up and tie them back to the harness. Don't cut them, someday you might want them back.

The tach wire will need a new termnal end- it's a ring termianl now and needs to be a 1/4 female spade for the HEI.

 

Hi

Why does it need a new wire pulled ?
Should be enough to shorten the resistor and disconnect the yellow wire from the starter, shouldn't it ? In reality, the yellow wire from the starter could even stay connected, would not harm the function at all.
Only difference to the old wiring is that the resistor is taken out . The HEI runs on full battery or charging power all the time.

Rgds. Günther

 

Hi Günther
I wil try to explain.

Why does it need a new wire pulled ?
Like TimAt said, the best way is to pull a new wire from the fuse box.
The reason for this is: You need need +12volt to the Hei.

Should be enough to shorten the resistor and disconnect the yellow wire from the starter, shouldn't it ?
The Resistor wire is about 135 ohm, when using this wire the voltage would be under 10 volt to the hei, and the hei will not work. (you can start it whith the yellow wire connected, and maybe it will run, but using the resistor wire i think you will fry the hei. (When it's less voltage the current increase. U=R x I) I don't think you could shortened it enough. But you can replace it.

In reality, the yellow wire from the starter could even stay connected, would not harm the function at all.
That's right, the yellow wire will give the hei 12 volt when turning the ign. key to start position, and when returning the key to run position the voltage on this wire will be 0 volt.

Only difference to the old wiring is that the resistor is taken out .
If you have a external resistor placed nearby the ignition coil, then the wire to the resistor is a common Cu wire, and you can use it.

The HEI runs on full battery or charging power all the time.

Rgds. Günther[/QUOTE]

Regards
Audun

 

Hi flyingman21,
I installed a HEI,
here's a link to my post.It may help???

http://forums.corvetteforum.com/c3-t...post1568679367
I've had NO probs (So Far- I Must have pleased the Corvette Gods).
Cheers
Gavin

 

Hi

I didn't know that there might be a resistor wire installed.
My 68 has a resistor installed between the wire. It lives just in front of the wiper motor. Shorting this one is dead easy.

Thanks for all explanations.

Rgds. Günther

 

All GM cars and trucks with points have the resistor wire installed. IF you run points systems on a full 12v all the time it'll cook the points. On the down side, that resistor wire has been known to fail. In the 60's in the dealership we used to run a new wire and a ballast resistor instead of replacing the harness.

 

as long as we're on this topic, does anyone know where to get a proper connector for the hei unit, rather than just using a spade connector?

 

Maybe someone like Lectric Limited? IT's a white connector with a tab that locks on the cap.

 

Regards
Audun[/QUOTE]

Just trying to correct a couple misunderstandings regarding the operation of the HEI system.

 

the best point to get the 12Vs from is the feed wire that feeds the stock resistor wire. it feeds the resistor wire from the passenger side of the main engine harness coupler. You need to locate it on the wiring diagram, so you know which wire it will be. It will be a red or pink #12 in one of the slots. Loosen the fuse block from under the dash by pulling it forward lightly and moving the two clip tabs outward to release it. It is behind the fuse block. Be careful with it, it and the wiring are old. Just slightly bend it out of the way. Locate the ignition feed wire above and trace it back to the harness, then cut it about in the middle, between the harness and feed block. Get some #12 stranded and some yellow butt splices and splice one end to the now cut wire stub coming out of the harness, use hard pressure when crimping it on and test it by pulling on it lightly.

There should be a hole with a plug it in above the block, pull the plug out and replace it with a grommet, most Ace hardware stores have a grommet selection tray. Feed the wire through, Now you have a ignition switch controlled, fused 12V source you can do anything you want to with. To return to stock, just remove the wire and butt splice it to the original wire going to the harness block. Be sure to disconnect your battery before you do any electrical work. Also, the resistance wire is 1.35 Ohm/ft C.

 

Thanks guys for all of the replies. I have a questions about the resistance wire. Is it running during both start and crank? Also, TimAT, I don't have that "IGN UNFUSED" unless it is the one labeled IGN. witch one would I tie into?

I also have some pictures of the pink wire that feeds the resistance wire. It connects to the ignition switch connector.

 

It is the IGN that you connect to.

I wired my DUI exactly as Tim described. Terminated the end of the existing resistance wire and tied it back just in case I would go back to points in the future. Mines a mech. tach so my tach terminal on the dist. goes to the rev limiter.

 

You can hook it to the pink wire. My preference is to just tie back the original wires without cutting anything. Someday, someone might want to go back to the original stuff.

SmokinBBC is correct-- the IGN terminal is the one you want.

 

SWEET! thanks for all the help guys!

 

It's hot during both RUN and CRANK, but during cranking, the yellow wire from the starter is electrically in parallel with it, delivering full non-resistor limited voltage to the dist. Not a problem because they use the same voltage source.

 

Keep those photo's coming.

I have a new harness and a Hei ignition installed bij a previous owner. I sure would like to know how you hook it all up.

 

OK, Thanks to everyone I figured this all out and posted pics to help out. The first thing to do is get the HEI kit from MAD. They have everything that you need to get the job done. This works a lot better if you have a nice new wiring harness. I disconnected the resistance wire and crimped on a Packard 56 terminal on the new wire.


I then installed it into the place where the old resistance wire is. According to the wiring diagram it is connected to the ignition wire that will be active during the START and RUN and provide the 12 volts that the HEI needs.

I then ordered some vinyl wrap from Lectric Limted so I can tie it into the wire harness and cover up the resistance wire and Yellow wire that are no longer used, but still there so if in the future someone can use it if they want. The other end of the wire gets a terminal that plugs into the BATT terminal on the HEI. Hope this helps

 

Good topic, very informative.

The connector is that this one.

 

What am I missing here guys?

The starter has a terminal that goes to the coil in a points setup. It's 0V when off and 12V with the ignition. Why not wire the HEI to it with a new wire? (btw, I've just installed an MSD streetfire in my '69)