GEN 3 how to change the resitor wire for HEI instruction. [Archive] - Chevy Nova Forum

: GEN 3 how to change the resitor wire for HEI instruction.


The Big Al
2nd-August-2010, 06:12 PM
One of the most common mistakes when upgrading or Nova's from a point ignition to a GM HEI or any HP ignition system is not changing out the resistor wire so the HEI will receive the proper voltage needed to operate correctly.

I did this today on a GEN 3 so thought I would share.


This is not correct and what is mostly found.
A resistor wire with a pig tail for HEI power connection sliced in.
Not a good thing! :no::no::no::no:
http://img811.imageshack.us/img811/5224/003as.jpg


First you need to remove the engine wiring harness from the firewall.
This will be located between the fender and brake master cylinder.
Power brake can make this aggravating to get to.
http://img801.imageshack.us/img801/885/005atp.jpg
Remove the 3/8 bolt and pull the harness away from the firewall.
http://img38.imageshack.us/img38/9149/006akc.jpg
http://img838.imageshack.us/img838/6700/008an.jpg

Notice how the harness will separate so you can remove only the engine part of the harness.
http://img402.imageshack.us/img402/4733/009aqm.jpg
http://img813.imageshack.us/img813/9572/011amd.jpg

Now you have the harness removed from the vehicle, you need to remove the resistor wire & terminal from the terminal block. This is a easy, just trace the wire and lightly squeeze the terminal and push and pull it out from the back side.
http://img440.imageshack.us/img440/2320/013ae.jpg
http://img9.imageshack.us/img9/1593/014anq.jpg
http://img3.imageshack.us/img3/6859/016ae.jpg


Now we make up the new wire.
you will need 24'' of a quality 14ga stranded wire (I prefer red in color)
2 GM specialty terminals NAPA part number referenced.
Use a quality crimping tool.
http://img52.imageshack.us/img52/162/017ak.jpg
http://img812.imageshack.us/img812/4429/032ajg.jpg

It is also easy to remove the factoy alignment terminal housing used on the HEI. With a pin tool you remove the housing.
http://img684.imageshack.us/img684/9968/022afg.jpg
http://img534.imageshack.us/img534/2590/029ax.jpg


Make up the wire with the new terminals and plug them back into the harness terminal block and HEI terminal housing. Re-install the wiring harness and your set.
http://img39.imageshack.us/img39/1360/028ab.jpg

Terminal for dist.
http://img560.imageshack.us/img560/5989/027agw.jpg
terminal for factory harness
http://img52.imageshack.us/img52/162/017ak.jpg

Installing the factory harness terminal is easy, just push it in. and make sure it is locked into place.
http://img20.imageshack.us/img20/2616/033ad.jpg
http://img707.imageshack.us/img707/7540/036an.jpg

FYI
AL



PS: It took me more time to post and edit pics than do the work on the car!

walkerjay
12th-August-2010, 12:50 PM
Just came from NAPA as I also need a few of these connectors.

They only showed two good numbers:

725145 & 725147

Apparently they only come in boxes of 50.

Who wants to go in on some?

The Big Al
12th-August-2010, 01:38 PM
Just came from NAPA as I also need a few of these connectors.

They only showed two good numbers:

725145 & 725147

Apparently they only come in boxes of 50.

Who wants to go in on some?

Pm me, I will sell ya 2 terminals or make up the wire for you just to plug in.

Al

patman
12th-August-2010, 01:57 PM
Nice writeup Al, thanks!

Tuckin20s
12th-August-2010, 05:10 PM
Al all I have to say is:notworthy:

walkerjay
12th-August-2010, 11:41 PM
Pm me, I will sell ya 2 terminals or make up the wire for you just to plug in.

Al

sweet. I'll assess what I need and get back to you.

walkerjay
23rd-August-2010, 10:40 AM
PM sent Al.

Are you familiar with the orange wires and clear fusible links with orange wiring near the horn relay area? Those wires in particular seem kinda soft and may need attention.

One last question: I meticulously cleaned my harness ends and adapters and have removed most of that gooey black stuff. I'm figuring its for water resistance, etc. What would be a good product to install in there as a sealant, if even necessary?

zman1969
25th-August-2010, 01:36 PM
PM sent Al.
One last question: I meticulously cleaned my harness ends and adapters and have removed most of that gooey black stuff. I'm figuring its for water resistance, etc. What would be a good product to install in there as a sealant, if even necessary?

Jay , Dielectric grease would would work for water repellant/sealer.

walkerjay
25th-August-2010, 05:04 PM
Jay , Dielectric grease would would work for water repellant/sealer.

cool. I'll look for it next time I'm at the parts store.

walkerjay
3rd-September-2010, 11:35 AM
Al,

In your pic showing the original white resistor wire, it looks like a thicker pink wire is going to that same terminal. Or my eyes deceiving me?

My wiring diagram shows the hot wire (coil / HEI) two spots across from the orange blower motor wire. My current harness already has a pink wire in that location (pink wire splits and runs to the electrical piece mounted on the column) Wondering if they both go to that same terminal at the fuse box.

The Big Al
16th-September-2010, 01:07 PM
Al,

In your pic showing the original white resistor wire, it looks like a thicker pink wire is going to that same terminal. Or my eyes deceiving me?

My wiring diagram shows the hot wire (coil / HEI) two spots across from the orange blower motor wire. My current harness already has a pink wire in that location (pink wire splits and runs to the electrical piece mounted on the column) Wondering if they both go to that same terminal at the fuse box.


Don't know that answer. On the few cars I have done the wire is capped and wrapped in the harness. I just remove it.

Al

Tarantula
6th-October-2010, 02:54 AM
:yes:Excellent info. Thank you!!

asteeler4life
25th-February-2011, 03:08 AM
This is good stuff :good post: AL, :cool pics:

Novaman Oscar
25th-February-2011, 04:05 AM
gonna be trying this out :yes:

Crimsontide12x
22nd-May-2011, 02:27 PM
Is this resistor wire why my coil pack burns out every 30 minutes??

The Big Al
22nd-May-2011, 03:37 PM
Is this resistor wire why my coil pack burns out every 30 minutes??

Coil pack?

More info needed.

MAKE MODEL & ENGINE.

RJ Harp
22nd-May-2011, 04:39 PM
Just curious. What happens if you dont do it the way you just posted? Or what could possibly happen?

Crimsontide12x
22nd-May-2011, 05:37 PM
250 inline 6
I took the ingone out of 77 nova. It's in my 62 right now
The distributor and coil are separate but the coil is
Square (maybe coil pack is not the correct term)
Burns out every half hour... I have the wire spliced in
The way you specifically said not to... Lol

The Big Al
22nd-May-2011, 07:29 PM
250 inline 6
I took the ingone out of 77 nova. It's in my 62 right now
The distributor and coil are separate but the coil is
Square (maybe coil pack is not the correct term)
Burns out every half hour... I have the wire spliced in
The way you specifically said not to... Lol


Need to eliminate the resistor wire, your coil is not getting correct voltage.

Al

OB_67_Nova
22nd-May-2011, 07:42 PM
Question for Big Al... if that pink wire is on the same terminal as the resistor wire and it is capped off, what voltage is on it ?

Crimsontide12x
22nd-May-2011, 07:47 PM
Al, thanks for the reply. The car in question(62 convertible) belongs to my dad... He is not doing so good health wise... Trying to finish the car before his health diminishes any further... I have 64 that has been setup and wired for a v8. The engine harness appears to be the same in both vehicles... Do you know If they will simply swap out?? also the 64 is spliced in at the distributor, but the car runs great... Does the 64 have the same resistor wire??

Thanks again for your help

The Big Al
22nd-May-2011, 10:27 PM
Question for Big Al... if that pink wire is on the same terminal as the resistor wire and it is capped off, what voltage is on it ?

I can not answer about the pink wire, could be start bypass.

During starting the coil gets 12 volts. the pink wire could be that 12 volt supply.

It's a good bet, most bypass are yellow.



Al

nreynolds
31st-July-2011, 08:30 AM
Al, thanks for the reply. The car in question(62 convertible) belongs to my dad... He is not doing so good health wise... Trying to finish the car before his health diminishes any further... I have 64 that has been setup and wired for a v8. The engine harness appears to be the same in both vehicles... Do you know If they will simply swap out?? also the 64 is spliced in at the distributor, but the car runs great... Does the 64 have the same resistor wire??

Thanks again for your help

I'm thinking 1st & 2nd gens came with the resister so the lead into the resister would be 12 volts already. It's the lead out that would be reduced to 9 volts.

roadiemanchild
5th-August-2011, 05:17 PM
I need to change my resistor wire also.

So how do I get two of these connectors without buying a box of 50 each?????
Paul

tsimpson
5th-August-2011, 06:01 PM
Send Big Al a PM, maybe he can hook you up.

graymond
30th-November-2011, 07:19 PM
Just did the upgrade. Without these pictures and the descriptions, that would have been a very difficult job. Working in the dark, so to speak. And the car started!! Even better.

Big Al you are great and thank you for taking the time to do this.

ray

steelrat
10th-December-2011, 01:14 AM
Is this just for HEI? What about when setting up for a 6AL box, with blaster coil and reg distributor?
thanks

graymond
10th-December-2011, 12:09 PM
I have the MSD box on mine. Did not use the HEI connector, but used the terminal for the firewall connector.

My box is the analog one so it may be more forgiving than the digital one. If you are putting the digital one in, I would do it for sure.

Not a hard task at all. I bought the connectors in a two pack at Alder Automotive here in White Rock.


ray

The Big Al
22nd-March-2012, 10:39 AM
FIXED, pics where dropped by host and now are re hosted.

By- request


AL

rquad
9th-April-2012, 07:50 AM
For those of us who know nothing about vehicle electrical systems, can someone explain why changing this wire is necessary? The reason given is "you need to replace the resistor wire", but that doesn't answer the question "why?".

Is the resistor wire too small to pass correct amount of current? Is its core material something that prevents current flow? Otherwise, splicing seems like it would work.

The Big Al
9th-April-2012, 12:38 PM
For those of us who know nothing about vehicle electrical systems, can someone explain why changing this wire is necessary? The reason given is "you need to replace the resistor wire", but that doesn't answer the question "why?".

Is the resistor wire too small to pass correct amount of current? Is its core material something that prevents current flow? Otherwise, splicing seems like it would work.

The resistor wire reduces voltage to the ignition coil, est 9 volts.

For the hei to work correctly it needs 11.2 -14.9 volts

Al

PMTcncMan
10th-December-2012, 06:58 AM
Great Post. I ran into this problem years ago when I switched to HEI. It took me a bit to figure out what the problem was.I only wish I had known about this beforehand, would have saved me about 20 hours of my life.

Nova Cane
26th-December-2012, 10:10 PM
With a HEI ignition you don't need a resistor wire,get rid of it,.A resistor wire cuts down the voltage to the original points ignition,which you no longer have. You need a 10 gage wire to produce enough voltage to your HEI so it will run right and not starve it to death from resistance. If you have to much resistance you won't have enough volts. Do the math from Ohms law

65novaken
26th-December-2012, 10:21 PM
after reading this when originaly posted.i ran out and did my 1st gen.its the same procedure:yes:

Inspector 12
27th-December-2012, 12:06 AM
With a HEI ignition you don't need a resistor wire,get rid of it,.A resistor wire cuts down the voltage to the original points ignition,which you no longer have. You need a 10 gage wire to produce enough voltage to your HEI so it will run right and not starve it to death from resistance. If you have to much resistance you won't have enough volts. Do the math from Ohms law

Your observation is exactly the point Big Al was trying to make. He was explaining the correct way to wire in the wire so it would not have the resistor in line so the electronic ignition or MSD box would get full voltage.

asteeler4life
2nd-April-2013, 01:24 PM
JUS' FINISHED DOIN' THIS TO THE VERT, HAD EVERYTHING BUT THE HEI CONNECTOR, FOUND ONE AT THE JUNK YARD AND :woot:


http://i950.photobucket.com/albums/ad343/asteeler4life/SMILIES/9a2c7466-4342-4bb1-83ac-5c87670df442_zpsdcf3e8bc.jpg

Sleeper72SS
25th-August-2013, 07:26 PM
Big Al, just pulled my harness apart and only found the pink wire that runs to the hei. Any thoughts no white ruff wire.


Sent from AutoGuide.com App (http://www.autoguide.com/mobile)

lwlevens
16th-October-2013, 08:57 PM
thanks big al great Illastration so very helpful took everything apart had to remove the brake booster pain in the *** buying the connectors tomorrow
thanks again

novascosha
14th-January-2014, 04:42 PM
After completing this, can you then remove the "yellow" wire coming from the starter that connects to the coil?

The Big Al
14th-January-2014, 08:04 PM
After completing this, can you then remove the "yellow" wire coming from the starter that connects to the coil?

maybe maybe not.

The way to check is, while the engine is cranking is the new power wire "hot"?
Check with a hot light.

If the power goes off while cranking the starter bypass needs to stay hooked up.

Hope this helps
Al

65novaken
14th-January-2014, 08:20 PM
I don't know how many times I have thrown this post out to members that ask how to wire their dist.
thanks again al for a very informative post
this should be made a sticky!!!!!!!!!!

mpv72
14th-January-2014, 08:32 PM
I did this a few years back but I bought the wire pre-assembled I believe from chevy2only

novascosha
15th-January-2014, 10:26 AM
maybe maybe not.

The way to check is, while the engine is cranking is the new power wire "hot"?
Check with a hot light.

If the power goes off while cranking the starter bypass needs to stay hooked up.

Hope this helps
AlThanks Al. My car already had an HEI on it and I am switching to an MSD. There was no resistor wire. The wires feeding the Dist. were pink and yellow. I have the front clip off, engine out and wiring removed so I can't test anything. I am trying to clean up some of the unnecessary wires so I thought I'd ask about removing the jumper wire. I think I'll leave it. I have some questions about removing some other wiring (TCS, idle stop, etc) but I'll start another thread for that.

novascosha
15th-January-2014, 07:41 PM
**EDIT** So after examining that pink wire closer, printed on the wire is " resistance do not cut". It also ran up along the harness a few inches then doubled back to the distributor location. From what I gather, the resistor wire is pink instead of white on a '72. Is it the wire itself that drops the voltage or is the voltage lower at the terminal?


Here is a link to my other questions if anyone cares to have a look.
http://www.stevesnovasite.com/forums/showthread.php?t=293921

sevenzeronova
15th-January-2014, 07:55 PM
Wire it self is the resistor.

novascosha
16th-January-2014, 10:56 AM
Wire it self is the resistor.Thank you. :thumbsup:

Dawg
20th-January-2014, 07:49 PM
Great write up Al.

Those who are wondering why there was a resistor wire to start with....it was because supposedly the ignition points would burn up in a short time.

The bypass wire was to give the ignition an extra kick when starting. Meaning while cranking, the coil received 12 volts, once started and you let go of the key, the coil would then only see 9 volts.

One question I do have....I recently replaced the points distributor in my Nova with a Mallory magnetic style. Mallory has said it doesn't need the resistor wire. However my coil is a Flamethrower. No word on it but I am presuming it can be safely driven with 12 VDC?

I still have my resistor wire. Car starts fine with it and no bypass. But I am wondering how much i am holding back with it on...?

Spencer 65 Nova
12th-February-2014, 09:06 AM
Would this be the same for a 65 as well?

The Big Al
12th-February-2014, 04:41 PM
Would this be the same for a 65 as well?

yes all 1974 and earlier

Al

slab
20th-February-2014, 06:54 PM
Just came from NAPA as I also need a few of these connectors.

They only showed two good numbers:

725145 & 725147

Apparently they only come in boxes of 50.

Who wants to go in on some?

I just called my local NAPA and they charge $0.99 ea and they only come in a pak of 50pc. just like has been stated. Does anyone have a source or some extras they would sell and mail up to me in Canada. I am willing to bet a pack of 50 in the US is half the price to boot!! Any help would be great. I'd gladly buy a five pack of ea plus all the shipping expenses. I thought I saw somewhere that there was a place that sold 5 packs.

Thanks
Rich

popatopsmith
24th-February-2014, 08:36 PM
Great write up Al.

Those who are wondering why there was a resistor wire to start with....it was because supposedly the ignition points would burn up in a short time.

The bypass wire was to give the ignition an extra kick when starting. Meaning while cranking, the coil received 12 volts, once started and you let go of the key, the coil would then only see 9 volts.

One question I do have....I recently replaced the points distributor in my Nova with a Mallory magnetic style. Mallory has said it doesn't need the resistor wire. However my coil is a Flamethrower. No word on it but I am presuming it can be safely driven with 12 VDC?

I still have my resistor wire. Car starts fine with it and no bypass. But I am wondering how much i am holding back with it on...?


Could someone explain in a little more detail what is meant by "the bypass wire"? I think whoever converted my 65 to HEI they ran a wire through the firewall and plugged it into the fuse box on cabin side of the firewall. I wonder if this is why sometimes my engine doesn't quit running when I turn the key off - even with the new ignition switch/key tumbler I just installed. Maybe I should re-wire my ignition consistent with this thread? But, I still don't understand what a "bypass" wire is and I would appreciate someone explaining that in a little more detail. Thanks,

M.Smith
Nashville, TN

Spitfireb
10th-March-2014, 12:40 PM
I just called my local NAPA and they charge $0.99 ea and they only come in a pak of 50pc. just like has been stated. Does anyone have a source or some extras they would sell and mail up to me in Canada. I am willing to bet a pack of 50 in the US is half the price to boot!! Any help would be great. I'd gladly buy a five pack of ea plus all the shipping expenses. I thought I saw somewhere that there was a place that sold 5 packs.

Thanks
Rich

Slab,
Did you find anyone to get you some connectors ? If so could you point me in that direction? I'm not too thrilled about buying a pack of 50 from NAPA for a few wire replacements hahah.
Alex

Spitfireb
10th-March-2014, 12:53 PM
Slab,
Did you find anyone to get you some connectors ? If so could you point me in that direction? I'm not too thrilled about buying a pack of 50 from NAPA for a few wire replacements hahah.
Alex

Here we go everybody!! I found the GM56 Series OEM Terminals sold here individually:

http://www.delcity.net/store/Packard-56-Male-Terminals/p_9292.h_151334.t_1.r_IF1003?gclid=CJyo3r-2iL0CFYyhOgod0m0A-g

Dawg
22nd-March-2014, 11:56 PM
Could someone explain in a little more detail what is meant by "the bypass wire"?

The bypass wire was a wire (yellow 20 gauge in my case) that ran from the starter (on the side marked with an "S") up to the coil hot wire, attached to the resistor wire off the fuse block.

The way it worked was this: when you would crank the starter over, a full 12 volts dc would come off of the starter, and go directly to the coil + terminal. This made for a brief hot spark to get the engine to start quicker. Once the engine started and you let off of the key, the 12VDC would cease in the bypass wire, leaving the resistor wire to provide the 9VDC to keep the coil firing.

The way you describe your coil as being hot wired to the fuse panel, should be fine as long as the connector is plugged into a terminal that is switched off when the ignition is turned off. This is how I wired mine up; when I converted from points to my Mallory ignition, I ran a hot wire off of the IGN terminal on the fuse block, directly to the coil +.

If you have it plugged into the terminal labeled "BATT", then yes it may not shut off when the key is switched off. Likewise, if the wire were plugged into the terminal labeled "LPS", it would not run unless the lights were turned on.

Hope This Helps