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Discussion Starter · #1 ·
Hello guys I am working with my carb but I had a member on here give me some information about the HEI ignition control modules. Mine is the common 4 pin design. I know there are a lot of cheapo ones on the net on ebay for like $12 to $15 bucks and stuff but I have done some digging around and it seems that a lot of the aftermarket ones has something of an issue of not having enough of what is called dwell time and it can allow the coil to overheat and burn out in short order and not last long.

My question is who makes good ignition control modules that is not the 7000 rpm plus ones that cost an arm and a leg and something I don't need and I never see anything north of 5500 rpm and I just want to know if there is such thing as a decent module out there that can run with a standard basic HEI distributor nowadays? I never heard of this effect of dwell on one of those before and I have a volt meter which can measure dwell which I never knew I had.

Is there a way I can test that? I was thinking about buying a different control module to see if its maybe adding to my other problem with my carb. Hope somebody can help me out here. I am just tired of throwing money at this thing and now auto store in my town anymore has testers to test them etc to see if there good. I have some spare ones on hand but there the cheap china ones I had left over from some old Skip White and Summit distributors.

I heard they don't have safety features in them like the older oem ones did.

It runs good and has good spark but I have heard of modules going bad and cause misfires or rough running at only certain speeds. Thanks folks for any help.
 

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Race it, Don't rice it!
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Stick with Genuine GM OEM and you'll be good to go.
DEI, Pertronix, I hear are good. No personal experience with them but the are popular around here.
The most important thing with ANY electronic anything is heat control.
 

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Discussion Starter · #4 ·
What brand is DEI by chance? Also on the GM ones I don't know anyone who carries them and last I heard they are made in China now as well but I don't know if that means anything if it being poor quality.I do have a Proform one on hand but don't know if it will work like I stated and burn the coil out and making it run hotter since its a performance module.
 

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Look for OE NOS or used on E Bay . Might get lucky.
Whe you install it be sure NOT TO USE DI ELECTRIC GREASE. IT does NOT transfer heat

You need this : https://www.amazon.com/Arctic-Silve...t=&hvlocphy=9006814&hvtargid=pla-404766512879

Also, A Good module, such a s GM will have an active dwell circuit that trims the dwell time at low rpms to keep the coil cool, but also increases at higher RPMs to ensure a solid sparkThey really are a pretty marvelous little integrated circuit
 

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Discussion Starter · #9 ·
I use heat sink compound that is used for PC chips to keep them for getting hot and it has worked wonders for me. I got a tube off ebay for that. I never use grease on them like some folks do. That is ok 95truck, I understand. Are you talking about OE Nos brand control modules on ebay? Sorry if I misunderstood what you stated. Thanks guys for the help.
 

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There used to be an EXCELLENT article on E BAY of all places, about the GM HEI module
dwell, active dwell, coil saturation,how it triggers ( on the ascending slope etc) also the differences in pickup coils,
It was chock full of good info
IIRC it was hosted by a guy with a store for auto electrical parts
 

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DUI. I can speak for them. They work well, and will last at least a few years!
Make sure you have some good grounds on your engine, and they will last longer... I always carry a spare in the truck with me too.
 

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Buyer beware the ad says:
  • Professional, premium aftermarket replacement
I would expect it to say OEM. My suspicion is it is made in china.

An NOS part is going to be as the original, these copies probably not. Try to obtain the old NOS replacement module. Not having the variable dwell feature on a lot of the copies is a killer as previously mentioned. Unfortunately no body tests thes modules for function so you don’t know which module is good.

When I first started using HEI, i had no idea how bad the market supply was. First one I got lasted a half hour. Then I started educating myself on the topic. And found that most cheapies are junk. The NOS design had circuits & features the copies didn’t. Not wanting to buy a mega dollar $$$$ race module I start looking for old NOS modules built by reliable suppliers back in 70’s & 80’s.
Above all, made in USA.
 

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Buyer beware the ad says:
  • Professional, premium aftermarket replacement
I would expect it to say OEM. My suspicion is it is made in china.

An NOS part is going to be as the original, these copies probably not. Try to obtain the old NOS replacement module. Not having the variable dwell feature on a lot of the copies is a killer as previously mentioned. Unfortunately no body tests thes modules for function so you don’t know which module is good.

When I first started using HEI, i had no idea how bad the market supply was. First one I got lasted a half hour. Then I started educating myself on the topic. And found that most cheapies are junk. The NOS design had circuits & features the copies didn’t. Not wanting to buy a mega dollar $$$$ race module I start looking for old NOS modules built by reliable suppliers back in 70’s & 80’s.
Above all, made in USA.
Sadly the real good GM modules were made in Indonesia, or Malaysia LOL
 

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I have not tried it yet but one can verify the dwell angle (time) the same as with a points system.
Something I’m gonna try when chance arises. It will be interesting to watch it vary with rpm.
I have no idea how much the dwell time varies on a good module. I suspect the coil has to be an “E” core to complement the low ohm requirement of the module, which I have.
 

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Cut and paste from the article you posted
C is the connection on the module for the coil negative

If the current limiter is in effect, the voltage drop on C may be much higher than 1 volt. The voltage drop on C is constant during current-limit mode. When the current limit mode activates, the voltage on C jumps from 1 volt to the necessary voltage to prevent any further increase in current, and stays there until the dwell period ends. (This may cause dwell meters and electronic tachs to give errant readings because they use the negative side of the coil to get their signal.)
 

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Discussion Starter · #18 ·
Wow thanks for the info guys and much appreciated. I did see those on rock auto but I don't know if the Acdelco ones are true GM quality or not. I have heard that AC delco company was sold and now stuff is made over seas and just put in a box with the name only. I don't know for sure. I can give one a try if need be.
 

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This was on the HAMB board, as of 2-1/2 years ago.

"BWD Select Part # CBE4" is made in the USA and supposed to be a good module.

I'm not an HEI module user, so I can't report one way or the other.
 

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Discussion Starter · #20 ·
Yes Ericnova72 those BWD ones were really good and Advance auto parts used to sell them but all they have now is carquest or something like that and they are China ones and nothing like BWD. I was stranded once and I bought one from Advance that was close to where my truck quit and that module lasted me for years but it got sold with my engine many years back and its still going that last I heard.
 
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