Another Chinese Part Story - This Time It's ACDelco

[Willys_MB]

Here is a cautionary tale for those of you out there running an HEI.

I installed an HEI two years ago that I got from a mid-70's C20. When I installed the HEI, I spoke with an old-timer at my local NAPA and he advised me that these modules can go out at random and that I should keep a spare module in my tool kit in my truck along with all of the necessary tools to replace it (a 1/4" nut driver, a flat head screwdriver, and a Philips screwdriver). They didn't have any in stock and I didn't need it right away, so I went home and ordered an ACDelco module to keep as my spare, but was a little disappointed to see that it was made in China when it got to my house. I figured that since it was ACDelco it should still be a quality part and moved on with my life.

It ran great until a few months ago when I started chasing what I thought was vapor lock. I was stuck on the side of the road and thought to myself "what about the ignition control module?" I replaced the chip, had it running after about 10 minutes, and continued on my way to pick up a yard of gravel. The wife didn't even notice I took longer than expected! That week I went to NAPA and got another module to keep in my tool kit. This time, I bought a NAPA brand chip FOR THE SAME PRICE, which is made in the USA by Echlin.

About two weeks ago, I started having problems that felt like I was dealing with an electrical short, but it was intermittent and I couldn't trace it down. This morning I swapped the chip out and she's running just fine now!

I'll report back in the future if I have any problems with the Echlin chip, but I highly doubt it will happen.

[HO455]

I had an HEI failure myself last week. (Post 707 in link) I wasn't able to get the truck running with a different module so I swapped distributors and got going. The point is that there is a pickup coil that can fail also.
You didn't mention if you are running a fact HEI or an aftermarket one. So it is likely you have a 35 plus year old pickup coil or one made overseas to the lowest bidder.

[LS short box]

Don't know if they provide a di-electric grease with they new module but back in the day when we replaced a module at the dealer ship there was a small grease pack that you put on the bottom of the module. I believe it was to help heat transfer.

[Willys_MB]

Originally Posted by LS short box

Don't know if they provide a di-electric grease with they new module but back in the day when we replaced a module at the dealer ship there was a small grease pack that you put on the bottom of the module. I believe it was to help heat transfer.

That's right, it's heat sink grease. So far each one has come with it. The Echlin chip came with a silicone based compound, but the ACDelco chip just came with a packet of it that was unlabeled. I cleaned both surfaces thoroughly with isopropyl alcohol and applied it following the instructions.

The original one I pulled off a few months ago didn't have any on there, or maybe it just dried up!

[Willys_MB]

Originally Posted by HO455

I had an HEI failure myself last week. (Post 707 in link) I wasn't able to get the truck running with a different module so I swapped distributors and got going. The point is that there is a pickup coil that can fail also.
You didn't mention if you are running a fact HEI or an aftermarket one. So it is likely you have a 35 plus year old pickup coil or one made overseas to the lowest bidder.

It's a mid-70's GM HEI. You made an excellent point there. It's almost the end of the dry season, so this winter I may rebuild this one or just end up coughing up the money for a newer one. They've gotten pretty cheap, but you get what you pay for

[Rickysnickers]

Not that I have one, an HEI, but I'm curious why these modules go out so often. What is the root cause? Sorry for the side distraction.

[Stocker]

Originally Posted by Rickysnickers

Not that I have one, an HEI, but I'm curious why these modules go out so often. What is the root cause? Sorry for the side distraction.

I'm not sure how often they fail, statistically speaking. Hope I don't jinx myself -- I'm still running the same HEI that I bought used and installed about 40 years ago.

[truckster]

Originally Posted by Rickysnickers

Not that I have one, an HEI, but I'm curious why these modules go out so often. What is the root cause? Sorry for the side distraction.

Usually it's heat. That's why the heat transfer grease or paste is so important.

[dmjlambert]

Yes, it's impossible to tell I think. Every time somebody asks here on the forum, and the question is asked did you use heat sink compound under it, the discussion usually deteriorates into discussion about dielectric grease or some other substance that you're not supposed to use, and we never find out from the original poster what exactly was used or if anything was used. Willys_MB is an exception to that and actually told us what was used. I have my doubts about silicone based compounds. The correct heat sink compound is a sticky usually white thick paste and is not similar to anything silicone I've ever seen. How it is applied makes a difference as well. Only a very thin spread of it is needed for optimum heat transfer. I think when I change mine I will not trust a packet that came with the module, especially if it is unmarked and appears to be anything like grease or silicone. I don't trust whatever packet of sauce or other substance some Chinese manufacturer throws in a box with a car part. I plan to buy a small tube of high performance computer processor compound. Any use of the inappropriate type or amount of compound should not be considered in any discussion of how long a module lasts, but how do you determine what was used or what people have done and make a count? I guess I'm going to jinx myself like Stocker did, my module is ancient and working fine, too.

[Steeveedee]

Back when I worked as a mechanic, the primary failure mode for an HEI was burn-through of the rotor due to lack of maintenance. They'd generally burn through at about 14k miles. I replaced hundreds of rotors (and sold a tune-up at the point), a handful of modules and ONE pickup. Fast forward a few decades, now it's all cheap Chinese crap, and module failures are far more common. I guess I got lucky- I bought a Mallory HEI that I put in an an engine in y2k that is now in my truck and working fine. It's only ever seen a cap and a rotor...and one vacuum advance can.

[CST10]

Had the exact same thing happen to me two weeks ago. AC Delco part. Replace with a Borg Warner made in USA.

[LockDoc]

Originally Posted by dmjlambert

Yes, it's impossible to tell I think. Every time somebody asks here on the forum, and the question is asked did you use heat sink compound under it, the discussion usually deteriorates into discussion about dielectric grease or some other substance that you're not supposed to use, and we never find out from the original poster what exactly was used or if anything was used. Willys_MB is an exception to that and actually told us what was used. I have my doubts about silicone based compounds. The correct heat sink compound is a sticky usually white thick paste and is not similar to anything silicone I've ever seen. How it is applied makes a difference as well. Only a very thin spread of it is needed for optimum heat transfer. I think when I change mine I will not trust a packet that came with the module, especially if it is unmarked and appears to be anything like grease or silicone. I don't trust whatever packet of sauce or other substance some Chinese manufacturer throws in a box with a car part. I plan to buy a small tube of high performance computer processor compound. Any use of the inappropriate type or amount of compound should not be considered in any discussion of how long a module lasts, but how do you determine what was used or what people have done and make a count? I guess I'm going to jinx myself like Stocker did, my module is ancient and working fine, too.

I always use a thin coat of Arctic Silver computer processor, heat sink compound. I have never had a module failure using this.

LockDoc

[LS short box]

I forgot about the rotor burn thru. I think was typically caused by bad plug wire that was arcing to the exhaust manifold or block. Early days of HEI GM had some quality/design issues with the modules and replaced tons of them under warranty.

[special-K]

I've never had an HEI module burn out in the many various GM vehicles I have had with that ignition

[palallin]

It was my (mis?)understanding that the only failure mode was digital: on/off. In other words, I thought that they either worked fine or didn't work at all. Do I understand from this discussion that partial failure--i.e. rough running--is a possibility? If so, it might explain a problem I am having that I can't find another explanation for.

[Willys_MB]

Originally Posted by palallin

It was my (mis?)understanding that the only failure mode was digital: on/off. In other words, I thought that they either worked fine or didn't work at all. Do I understand from this discussion that partial failure--i.e. rough running--is a possibility? If so, it might explain a problem I am having that I can't find another explanation for.

That’s right. From what I read, a lot of times it replicates vapor lock. After dealing with this issue I now think it’s possible to have other issues. I was also getting small backfires at higher RPM’s, which I thought was due to me not adjusting the carburetor after moving from elevation 600 to 2500. No issues today and I put ~50 miles on it.

[1971 GMC SHORTY]

Originally Posted by Willys_MB

Here is a cautionary tale for those of you out there running an HEI.

I installed an HEI two years ago that I got from a mid-70's C20. When I installed the HEI, I spoke with an old-timer at my local NAPA and he advised me that these modules can go out at random and that I should keep a spare module in my tool kit in my truck along with all of the necessary tools to replace it (a 1/4" nut driver, a flat head screwdriver, and a Philips screwdriver). They didn't have any in stock and I didn't need it right away, so I went home and ordered an ACDelco module to keep as my spare, but was a little disappointed to see that it was made in China when it got to my house. I figured that since it was ACDelco it should still be a quality part and moved on with my life.

It ran great until a few months ago when I started chasing what I thought was vapor lock. I was stuck on the side of the road and thought to myself "what about the ignition control module?" I replaced the chip, had it running after about 10 minutes, and continued on my way to pick up a yard of gravel. The wife didn't even notice I took longer than expected! That week I went to NAPA and got another module to keep in my tool kit. This time, I bought a NAPA brand chip FOR THE SAME PRICE, which is made in the USA by Echlin.

About two weeks ago, I started having problems that felt like I was dealing with an electrical short, but it was intermittent and I couldn't trace it down. This morning I swapped the chip out and she's running just fine now!

I'll report back in the future if I have any problems with the Echlin chip, but I highly doubt it will happen.

Did you use A good quality Thermal paste compound, Found Out Years ago That Lil bit That comes in Kit Isn’t Enough Causing Module to get hot and Premature Burn Out, never had one burn out after that I Was a Chevy Technician 20 years

[rsgt]

On the Team Chevelle forum there is a guy who worked for gm and helped develop the HEI. This is what he always says modules usually don't just fail. From his info, almost all module failures are from coils starting to fail, overloading the module.

[special-K]

Actually, I take my prior comment back. The first HEI I ever had I installed in a '71 K/20. I bought a rebuilt GM unit. One day I shut the truck off to load and when I went to start it only cranked, no spark. I replaced the module and about a week later, same thing. Upon closer inspection I discovered both wire from base to coil have tiny breaks in them, I could see patina green copper. I had a '77 parts truck sitting there, stole that wiring off it, put it on the '71, and it ran for many years without an issue. That HEI is powerful and sensitive. I did smear it up real good both times

[HO455]

I can add that my Burban was running fine. I had been on freeway for 15 minutes and had exited and had traveled about 5 more miles at 40 MPH with several stop lights.
The engine gave no warning, it just died. When I tried to restart it it would only pop once every 5th or so revolutions.
When I got the module out it was very hot. To hot to hold. There was a white heat transfer compound under it.
Also the HEI in the Burban was an aftermarket unit.

[ForcedInduction355]

Originally Posted by HO455

I had an HEI failure myself last week. (Post 707 in link) I wasn't able to get the truck running with a different module so I swapped distributors and got going. The point is that there is a pickup coil that can fail also.
You didn't mention if you are running a fact HEI or an aftermarket one. So it is likely you have a 35 plus year old pickup coil or one made overseas to the lowest bidder.

I have to agree here. I was chasing the same type of problem and when you change a module, you wiggle wires which go into the pick-up coil. After I changed modules it ran, but then in a few days it didn't again. It turned out that the pick-up coil or wires going into it were bad. Changed it out, and never had an issue again. Note, you have to remove distributor and dist gear and shaft to change the p/u coil. But it is still pretty easy.

[Willys_MB]

Originally Posted by ForcedInduction355

I have to agree here. I was chasing the same type of problem and when you change a module, you wiggle wires which go into the pick-up coil. After I changed modules it ran, but then in a few days it didn't again. It turned out that the pick-up coil or wires going into it were bad. Changed it out, and never had an issue again. Note, you have to remove distributor and dist gear and shaft to change the p/u coil. But it is still pretty easy.

Interesting. Sounds like I’m heading to NAPA this week to get some HEI parts and solve this problem. At first I thought you guys meant the ignition coil until you said the bit about basically disassembling the whole distributor. Time to look into doing a full rebuild I guess!

[ForcedInduction355]

I thought it might have been mis-construed as it would be easy to assume it was the ignition coil. This is what is looks like typically. Good Luck partner.

[Willys_MB]

Just so we’re all looking at the same thing here. It does look like you’re talking about the pickup coil.

[Willys_MB]

Originally Posted by Willys_MB

Just so we’re all looking at the same thing here. It does look like you’re talking about the pickup coil.

Alright.. pic didn't load. Here we go again! This diagram shows it as a "pole piece."