Technical My car has an HEI, can I ask a tech question here?

Terranova. I had the exact same issue. IDENTICAL!!!! I first replaced the ignition switch first & that seemed to fix the problem temporarily. Then started happening again. I then replaced the plugs, distributor cap, a few other things I can't quite remember everything, but I failed to change the item pictured above. I've been calling it an ignitor as that's what it's been called by other, but as the other guys said it's an ignition module. I replaced that & boom. Ha k on the road with no issues. Hope this helps.


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FWIW, I have the experience of dealing with breaker points and HEI, and taught and self-trained toubleshooting. I have feeler gauges and a working dwell meter.
I'm not a goose in a snow storm.

 

That rotor burn-thru problem-
when GM first started using HEI ignitions they specified .060 plug gaps.
It didn't take much aging before the resistance to current flow started causing the spark current to find an easier route... arcing thru the rotor to the shaft. often "welding" some rough spots in the advance mechanism, ( making the advance to stick sometimes)
A quick and easy fix was to suddenly require a "mere" .045 gap to reduce the tendency for the spark to find an easier route. better rotors helped too.
if .060 gap was too much an impediment to flow on the proper path, a .045 gap was easier to reliably jump.

why be ordinary?

 

You can take your module out and take it to Advance and have it tested. Their machine puts a load on it . If it is bad it will show in the test. Better than the shotgun method of repair. Just throw parts at it until it is fixed. A test light and a volt/ ohm meter is something you should become friends with.
It could be something as simple as you have too small a wire to the dist. You could be getting voltage drop.

 

Lots of good info and I appreciate all the feed back. Many angles to approach it from.

I went out and did what thought was easiest which was to take off the top and give a quick visual, to make sure the ground was actually there and see what shape the wires are in.

IMG_5296 by Terranova posted Jul 6, 2017 at 10:26 AM

IMG_5297 by Terranova posted Jul 6, 2017 at 10:26 AM

It looks to me like the wires are in decent shape and the ground is there.

Does it look like it's been arcing in the spots closest to the plug terminals?

Planning on digging under the dash to check the ignition switch later today. Need a new battery for the multimeter.

 

"as long as the key stayed on after it died, there was no juice
Second session, if I turned the ignition off and back on, the juice would come back up and it would start right up."

Again, we're all over this HEI thing, but if the engine dies ,due to HEI failure, there is still "juice".
The gauges, the radio, fans, elec. pump, etc. are all still live.

 

I carry a spare module in my hot rod. there not that expensive . I have used it once. Don't forget the white heat transfer grease. My system acted just like yours when it went bad.

 

Mark Yac is right. what do you mean by no juice? If the car has no battery power or the HEI as no battery power the problem is not the HEI
The wires you are looking at are the coil wires. The wires that become brittle are to the module, they are under the cap

 

Hei module

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Southcross is right HEI's take a full constant 12 volts. My HEI's all get a 12 ga wire to power them never a problem.

 

From experience, Modules don't usually **** out on their own, there is usually another problem causing them to **** out. A coil going out will do it for sure. Bum HEI coils also will fail when hot and then work again when hey cool off if they aren't completely shot. I drove 150 miles one way to fix my dad's car on the side of the road over that one.
On my 71 GMC with Hei I found one damned important thing and that is you have to have the correct clip on the power wire to the distributor and not a female slide. A female slide terminal will work but over time will loosen up just enough to not make contact and causing the engine to die. Mine had a habit of doing it at 3 AM on the way to work when it was raining like a cow ******* on a flat rock. If it doesn't have the correct terminal end on it that locks on the cap get one.
Years ago NAPA Echlin put out a pamplet on trubleshooting an HEI good info and I copied my copy and have it on my photobucket album. You will probably have to save it to your computer and enlarge it to read it but it walks you through testing one.
Here: http://s173.photobucket.com/user/mr48chev/library/Napa HEI service info bulletin?sort=3&page=1
There are 8 pages and it is a valuable resource that I have referred to many times over the past 35 years.

 

I would like to see how you did that. Please.

Ben

 

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So, I pulled the module and took it to get tested at the local adavance. Took all three people there fumbling with the machine like a chimp who just discovered a turtle to figure it out. Ran it three times. It came back ok all three times.
Well ****, I'm gonna have to chase down something else.

I did find some crud on the inside of the terminals in the cap.

IMG_6034 by Terranova posted Jul 13, 2017 at 10:51 AM

So I cleaned that off with a small file and I also ran it across the contact on the rotar.

All the wires inside looked good and connections seemed solid.

I ****oned it all back together and took it out for a spin. Probably over five miles to the local gas station and back. Left it running while I g***ed up.

No issue. Nothing happened.

Only variable was the hood was off so no heat build up like normal.
I'll throw the hood on here after I find some new screws for it and let you know if anything changes.

Thanks for all the feedback and suggestions everyone
T

 

Thanks for the update.

 

Bump.

I put HEI in my old Corvette 20 some years ago, with the module mounted externally on a heat sink. Never a misfire. Today I warmed it up, backed out of the driveway and it quit. No restart for about 30 seconds, then made it back into the driveway. Same thing, runs for a bit then dies. I put a timing light on it, spark quits then it dies. I touched the module, smoking hot! After reading this thread I guess it's finally packed it in.

My question: Are all 4 pin modules the same as far as performance? I see ads for low saturation modules, performance modules, blue modules... I'm running one of those big ugly yellow Accel super coils btw.

 

I've always just bought the 4-pin modules and never found a difference in performance or timing changes. (in case some might have built in advance or retard at certain rpms) none that I have noticed.
I think that came later with the 6pin or 8pin modules or whatever. The 4pin was the simple system
If a parts guy insists on a year and model, I just tell them I have a 1976 Chev pickup truck and never worried.
When I built racing HEIs in the past, I have ordered those special modules that were supposed to go along with the same brand aftermarket coils, to include in the buildups, but I am not aware of a difference they actually made.
I DID however specify the "yellow wire" coil in many instances where a very large engine was sapping the cranking battery during startup.
I read that the "yellow-wire" coil has a higher voltage step-up than the "white wire" hei coil, and found that always did a better job of starting my big big Caddy motor when the straining starter was sapping my battery voltage. It solved a hard-start problem for me.
I dono know why I mention that here...


why be ordinary?

 

ok, ok
I wrote that I moved the hei module to under the dash for simplicity.
What I actually did was mount TWO .
Same thing exactly as I said, except that I simply flip a switch instead of unplugging old, and plugging in the new.
This is a pic I just took right now.
12+ years so far, and no failure.
If it ever happens, all I do is flip the switch to activate the fresh one and keep on driving.
I did that exact same thing with my fuel pumps so I never have a roadside repair unless a tire goes.
I've been taking my old cars cross-country as family cars for decades, and haven't ever asked for a tow yet.





It's not exactly pretty, but it never lets me down.


why be ordinary?

Ok, you can simply run 4 wires from the 4pin module straight to the 4 wires in the distributor, and it works great.
BUT now with the pictures, I have to go into the other details I was too lazy to write about.
I used a switch from Radio Shack that was a
double-throw 4 pole switch.
Double Throw means I have an OFF middle position, an A position for module (1), and a B position for module (2).
4-pole means that the switch can turn on and off FOUR items at the same time without the 4 items cross-connecting to each other. .. in other words it's 4 side by side switches operated by one handle.
I ran the 4 distributor wires to the center terminals, and then the 4 terminals on one side went to module(1), then the 4 terminals on the other side ran to module (2).
That means I don't have to stop the truck to change a module that fails - I just flip a switch and keep driving.
After a couple roadside fuel pump failures in the 1970s, I have been running my fuel pumps the same way.
DONT STOP, FLIP A SWITCH AND KEEP ON DRIVING!!!

 

P.S. the condensor you see is an ordinary noise suppressor that is used on HEIs. It was a precaution in case the long module wires were sensitive to picking up interference or mistaken signals along the way.
I have never had any indication of it being needed, it was "just in case"

Sorry for being so long winded.
I wanted to make sure I wasn't misunderstood.

why be ordinary?

 

That set-up will also work as an anti-theft switch in the off position won't it?

 

HAMB to the rescue!

 

Thanks DTBD. I suppose the 'low saturation' modules might decrease dwell time?

https://www.skipwhiteperformance.co...-module-for-chevy-hei-distributor-6917_79983/

 

I also use it for anti theft in the middle position.
A similar switch was very handy when I was watching my dad fade away with Alzheimer's.
I tried to help him live in his own home as long as possible.
He would call me to say his car wouldn't start. I would come over and start it, then say "Dad, while I'm here, why don't I drive you on your errands?"
He was always fine with that.
It worked out well.

why be ordinary?

 

This has become a real interesting thread and moving the module inside with wires running to the distributor might clean up some conversions plus save wear and tear on the module.

 

that's more detail than I know...

why be ordinary?

 

This is an update to my last pictures posted here.
The HEI setup in my pictures has never failed to start the Stude truck since my kids were little, a couple decades ago at least.
Right after I bragged about that, it acted up and had a very rough time starting.
Soooo I suspected it was an unreliable ground problem caused by the modules and mounts dangling from the hanging wires all these years.
I thought it was time to yank the distributor, wiring& controls, and freshen things up.
It was very much overdue. The rotor had loosened long ago and had been rattling around inside the cap for quite some time, everything inside the cap had a black (conductive?) coating, terminals eroded a bit . The advance mechanism had hardened lube crust built up enough to make it stick, etc etc.
Along the way of making things fresh again, I decided to mount the remote HEI modules in a better and safer manner rather than dangling from a cable.
After looking at the new pic, I see that I could have done a much prettier job on the new aluminum heat sink I found on ebay.
If I took the time to lay out the bolts in a nicer pattern, or hid them, and if I would have very slowly milled the hole for the switch instead of drilling it, the fins would have looked nicer instead of bent on the ends.
BUT I now have a much more trustworthy ignition system again with a better chance of going another 15, 20, or more years.
It fired right up on the first crank again!
This is the new module mounting under the dash, and the selector switch that makes the very unlikely far-from-home roadside repair a simple matter of flipping a switch and simply driving on, instead of digging out the tools.
Not as pretty as it could have been done, but it'll go for another long long time.




why be ordinary?