Internal vs. External Coil in GM HEI - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 11-10-1999, 03:09 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Internal vs. External Coil in GM HEI

I have purchased a distributor from a 78 GM 250. It has the external coil. The distributor however doesn't have the three wires from it that are described in Larry Maggio's description. Is that because of the external coil? Also, what is the best way to clean this distributor and coil?

Dirt is good. Speed is good. Scabs are good. Life is good.
Sponsored Links
Advertisement
 
post #2 of (permalink) Old 11-10-1999, 09:27 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

If this distributor has an external coil then it isn't the HEI that you were looking for. The HEI will have the coil(brain) on top of the distributor cap and have the wires that were discribed.

post #3 of (permalink) Old 11-10-1999, 10:40 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

Don't rush out and buy a different distributor just yet. The one you have will work. I don't know the wiring schematics, but I would bet that Larry M. will read this post and will probably know what you need to do differently. I check in on the Howell users group once in a while and I seem to recall some guys there using the external coil HEI setup.

Sponsored Links
Advertisement
 
post #4 of (permalink) Old 11-10-1999, 11:04 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

Unfortunately I have seen only 'installed' external-coil HEI and I dont recall the wiring layout.

The problem I'm having is that I was sure the external coil HEI's were used only in 75&76. I think you are fine to use what you have as long as it isnt computer-controlled and being a 1978 HEI I dont think you need to worry about that.

What type of vehicle was it?


For cleaning really dirty HEI's I use a wire brush and brake parts cleaner. You can dismantle these things almost entirely and do a thorough job if needed. Make sure to relube things when done.


Regards,

LarryM
85 CJ7, 350TBI ,T19 4spd
'00 TJ Sport
post #5 of (permalink) Old 11-10-1999, 02:52 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

Is it possible it is NOT an HEI distributor? Are there non-HEI distributors from '78 Chevy truck I-sixes?

Dirt is good. Speed is good. Scabs are good. Life is good.
post #6 of (permalink) Old 11-11-1999, 11:44 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

Our son picked up two of these External coil HEI's for me.
I did not look at them till this fall . Have all the parts[wires , gear,]
The pick up looks like a HEI so then if you would have a matching
coil would it not be the same as a HEI??????
Could you change it to a coil in the cap type HEI????????-

post #7 of (permalink) Old 11-12-1999, 12:14 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

Anything is possible.

Last two post have got me stumped.


LarryM
85 CJ7, 350TBI ,T19 4spd
'00 TJ Sport
post #8 of (permalink) Old 11-12-1999, 04:46 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Internal vs. External Coil in GM HEI

You can convert between internal and exernal coils, the base is identical[img]/wwwthreads_images/icons/cool.gif[/img]. The tan/red/lighter color wire is power, the brown/black wire is trigger. You can wire it directly to an external coil, I used a 12V model out of an 86 Astro that outputs 50K volts same as the internal coil[img]/wwwthreads_images/icons/smile.gif[/img]. To mount an in-cap coil you need the wiring plug, the center wire (not marked) is a ground wire for the coil. I like the external coil because the cap is so much shorter, with a good coil the perforemance IS the same (I converted when I put on my TBI).


~|_____
__|____|__
/-[img]/wwwthreads_images/icons/smile.gif[/img]||||[img]/wwwthreads_images/icons/smile.gif[/img]-\
([img]/wwwthreads_images/icons/cool.gif[/img])-o--([img]/wwwthreads_images/icons/cool.gif[/img])

Randy 80 CJ5
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome