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Discussion Starter · #1 · (Edited)
Hi guys, went with a Summit $89 HEI when I did my engine a few years back. 400 plus hp 400 sbc. Looking to improve now. Have you guys been having better luck with DUI or Perrronix or others? Whole distributors or replace the coil and module? I like the fact that I can get a Pertrinix with a Rev limiter especially since I column shift at the track, but want to hear what's working for everyone lately. All the posts I found were old.

I should mention this is for a street driven car that I put up to 5k miles a year on. Need reliability and vacuum advance.
 

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Previously using a MSD crank trigger and (timing-programmable) Daytona Sensors CD1 box. I am now back to using a locked-out MSD small cap vacuum advance billet distributor with the Daytona Sensors Box. Installed B28 vacuum advance unit (all in by 8" vacuum) and limited to 12 degrees.

Daytona Sensors box handles the centrifugal-like curve, rev limiter, and start retard. Vacuum advance is there to help with mileage. If only the distributor was as steady as the crank trigger......
 

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Has the Summit $89 failed you? Or is it vacuum advance you are looking for? And while electronics are good stuff, some of the stuff lately doesn't seem to have the lifespan that we had just a few years ago. I would be more inclined to install a separate RPM limiter.
 

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Your summit Hei already has a vacuum advance that is adjustable if that is what your wondering on that part unless I misread to fast. On the Summit Hei I used several of those over the years and I had two different builds that were over 400 plus HP and a mild performance camshaft in the [email protected] 50 plus above range clear up to [email protected] plus range and I ran it as is with no issue to 6500 rpm with never any issues. Only problem I had once was an improper installed carbon button and it burned through the cap but was an easy fix.

I ended up going with a MSD CDI box and left the coil that came with the Summit HEI and it ran excellent and I wondered if the coil could be better and put a different one in that was supposed to be more power and I saw no advantage in anything and it worked just as good as you could ask for and both of them lasted the time I had my builds for many years before I sold them. To me for an everyday street cruiser that sees more just average driving vs anything else its more then adequate for the job without having to needing to be a fancy billet super high output everything in order for it to perform and be up to the task of what your engine needs.

Unless your doing all out racing and need every square inch of every bit you can get then I think anything outside of adding a CDI box of any brand is just overkill for a basic cruiser. In my 20 plus years of more builds from mild to wild that I can remember, I have always just used a basic HEI that was never a super fancy one and it with or without a CDI box has been more then enough for me. The only thing I would question that on how long something would last are the coil and the control module as unfortunately the old days of something lasting for a really long time are a long shot at most even on the more expensive brand name stuff.

They don't make things like they used to even on the supposedly better quality name brand stuff like Pertronix or MSD stuff that is way more up in price. I just go on ebay and buy up some old stock BWD brand coils and control modules and so far if something has went bad I just replace them as needed. Its the China stuff that can either last a long time or crap out in short order and similar results with the more expensive stuff.

I had a brand new Hei distributor that was not very old at all and was not the Summit one but Jegs $89 price range and I ran it for only a few years and I added a Pertronix digital CDI box that was $225 and the Pertronix box went bad in less then a month and just quit working. I replaced it but have yet to put the new box on. Shortly after the Jegs distributor magnetic pickup coil went bad and instead of taking the whole distributor apart to replace it, I just took all the good parts off of it and threw the rest in the trash as for just a little bit more I just got a new Hei from Summit and stabbed it in and has been running fine since and I just kept the left over parts to keep as spares to carry in my truck in case something goes bad while I am on the road.
 

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Discussion Starter · #5 ·
The Summit HEI hasn't been giving me any specific issues, just looking to upgrade. I wouldn't feel bad spending more than $89 on the distributor when I have who knows how much into engines. I thought it would be a good time to upgrade.
 

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Has the Summit $89 failed you? Or is it vacuum advance you are looking for? And while electronics are good stuff, some of the stuff lately doesn't seem to have the lifespan that we had just a few years ago. I would be more inclined to install a separate RPM limiter.
The "short lifespan" definition is called * EVOLUTION of DESIGN * , constant change or improvements being made but we all know the changes to what ever is its made to ware out in a short time so you have to buy another.
 

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The "short lifespan" definition is called * EVOLUTION of DESIGN * , constant change or improvements being made but we all know the changes to what ever is its made to ware out in a short time so you have to buy another.

Yes, we have been so indoctrinated to use once and throw away. What you say is so true. Everything it seems has shorter life than the original products of previous years. Home appliances is the worst. And fixing or repair in many cases is not possible. Things are not designed to “fix” because the suppliers want you to buy another to replace it so they have a forever supply of $$$$$. Ignitions are a good example of this no fixing it mentality. This why I build my own HEI with common inexpensive over the counter parts that I can obtain readily. I know for a fact these components (HEI module, magnetic pickup, & coil) will be short lived. Thus I carry spares. Sometimes I think why not just go back to points ignition…………
 

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Yes, we have been so indoctrinated to use once and throw away. What you say is so true. Everything it seems has shorter life than the original products of previous years. Home appliances is the worst. And fixing or repair in many cases is not possible. Things are not designed to “fix” because the suppliers want you to buy another to replace it so they have a forever supply of $$$$$. Ignitions are a good example of this no fixing it mentality. This why I build my own HEI with common inexpensive over the counter parts that I can obtain readily. I know for a fact these components (HEI module, magnetic pickup, & coil) will be short lived. Thus I carry spares. Sometimes I think why not just go back to points ignition…………
Funny you mentioned "Home Appliances" we have had a Sears Kenmore 27 cf Frige for the past 34 years now it uses 6.5 amps and if you go to where Frigs are sold and look at the amps the new ones use they say they are the most Energy Efficient models at 6.5 amps, WOW in 34 years the new ones HAVEN'T gotten any better in the amperage department. By the way we haven't ever had an Service Man service our Kenmore.
 

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Your summit Hei already has a vacuum advance that is adjustable if that is what your wondering on that part unless I misread to fast. On the Summit Hei I used several of those over the years and I had two different builds that were over 400 plus HP and a mild performance camshaft in the [email protected] 50 plus above range clear up to [email protected] plus range and I ran it as is with no issue to 6500 rpm with never any issues. Only problem I had once was an improper installed carbon button and it burned through the cap but was an easy fix.

I ended up going with a MSD CDI box and left the coil that came with the Summit HEI and it ran excellent and I wondered if the coil could be better and put a different one in that was supposed to be more power and I saw no advantage in anything and it worked just as good as you could ask for and both of them lasted the time I had my builds for many years before I sold them. To me for an everyday street cruiser that sees more just average driving vs anything else its more then adequate for the job without having to needing to be a fancy billet super high output everything in order for it to perform and be up to the task of what your engine needs.

Unless your doing all out racing and need every square inch of every bit you can get then I think anything outside of adding a CDI box of any brand is just overkill for a basic cruiser. In my 20 plus years of more builds from mild to wild that I can remember, I have always just used a basic HEI that was never a super fancy one and it with or without a CDI box has been more then enough for me. The only thing I would question that on how long something would last are the coil and the control module as unfortunately the old days of something lasting for a really long time are a long shot at most even on the more expensive brand name stuff.

They don't make things like they used to even on the supposedly better quality name brand stuff like Pertronix or MSD stuff that is way more up in price. I just go on ebay and buy up some old stock BWD brand coils and control modules and so far if something has went bad I just replace them as needed. Its the China stuff that can either last a long time or crap out in short order and similar results with the more expensive stuff.

I had a brand new Hei distributor that was not very old at all and was not the Summit one but Jegs $89 price range and I ran it for only a few years and I added a Pertronix digital CDI box that was $225 and the Pertronix box went bad in less then a month and just quit working. I replaced it but have yet to put the new box on. Shortly after the Jegs distributor magnetic pickup coil went bad and instead of taking the whole distributor apart to replace it, I just took all the good parts off of it and threw the rest in the trash as for just a little bit more I just got a new Hei from Summit and stabbed it in and has been running fine since and I just kept the left over parts to keep as spares to carry in my truck in case something goes bad while I am on the road.
Eric, not to change the subject but How the he!! are you doing these days. Finally getting the rest of my trucks wiring harness and will be ready to fire it up for the first time in 6 yrs. Then I'll see how I or (we) did on the Holley re build. PM me if you want. aka Marvin mjgord51
 

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Read an article I think bout DUI, said they will curve a dist to your app

Also I don't know the name of it but there is a dist you can tune with your phone. Some peeps like it, never tired one myself but I'd like to maybe someday.

Got a programmable MSD box that I've been meaning to play with and even Daytona sensors. If I ever get my car done I have a vid that I'm gonna make bout modding an HEI in various ways LOL
 

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Read an article I think bout DUI, said they will curve a dist to your app

Also I don't know the name of it but there is a dist you can tune with your phone. Some peeps like it, never tired one myself but I'd like to maybe someday.

Got a programmable MSD box that I've been meaning to play with and even Daytona sensors. If I ever get my car done I have a vid that I'm gonna make bout modding an HEI in various ways LOL
We used to go to a couple of different garages and get a "distributor curve" with the Sun machine, but as we were always told - this gets you in the ballpark - it still needs to be tuned for your engine.

There is a real misunderstanding today and in the past of what "tuning an engine" means and I am speaking of getting the maximum out of it with the current combination of parts. All of it has to work together and when you start working with fuel curves, ignition curves, valve settings, timing adjustments you can easily see that there are a myriad number of combinations and one of those is going to be the absolute best for your engine given certain conditions - yep, we can never forget about the atmospheric conditions the engine is operating in either.
 

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Discussion Starter · #12 ·
I wound up ordering a Pertronix upgrade kit with a new coil, cap, rotor, module and spring kit. My plan is to use it to rebuild an HEI from my stockpile of parts distributors. That way I can compare it to the performance of the Summit unit.
 

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I wound up ordering a Pertronix upgrade kit with a new coil, cap, rotor, module and spring kit. My plan is to use it to rebuild an HEI from my stockpile of parts distributors. That way I can compare it to the performance of the Summit unit.

I will suggest if the Summit unit was fully functional that you will not see or feel any difference in the pertronix unit if the coil is an “E” core, on both.
 

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Just make sure you use the correct coil for the HEI dist you rebuild, some places use to sell both but it's become less common. Yellow & Red or White & Red, I don't rem all the details or what came with what but they are different polarity I think. Some say it's bout what side the starter is on or the main ground is located, think my C3 & C4 are yellow and my TA was White(if that was even the orig dist for it). It'll run with either coil but be a bit off and may start kinda hard. I put the TA dist in my C4 since I already rebuilt it and then later when I went to use a MSD box w/o the HEI module it went bonkers with two diff boxes(one new) but was fine back with the module. Only remembered some time later bout the diff coil wires and still have not got around to trying the msd again wires reversed.
 

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Unless the stuff in your summit distributor is bad I doubt you will see much difference especially in low rpm driving and below 5000 rpm. I once had taken my truck to a shop and had my engine hooked up to a oscilloscope and I had a performance distributor in it and it was listed as producing 50,000 volts or so and the scope hardly showed anything close to that and from what I read the coil may be listed for x amount of volts but that amount is not always used by the engine as it only needs x amount of voltage to get the correct amount of burn and voltage to keep things working in the best it can do for said parts being used.

I wish I could explain more but I am very rusty on some of the more advance stuff on the whole effect on how it all works and the technical stuff but maybe someone like Bogie or a more knowledgeable person can write more in here.

I have used just oem replacement coils from the auto part stores such as BWD which seems to have worked good for me in the past when I had to replace things and also using just BWD control modules and it has ran free from any problems up to 6000 rpm with no issue.

The aftermarket name brand stuff I don't know if they really make much of an upgrade on things to a certain degree on just a daily driver type of a deal and from my experience about the only place I have seen anything different wise on working issues is the control module more then anything else. Also the bushing in the cap can be an issue as well as on some of the more robust control modules and higher output coils you want to have a low resistance carbon button in the cap to get the best of everything or if its one that has more resistance it can cause the cap to melt in that area but I have never had that happen with what ever came with my distributor. Hope you will find what your looking for.

I have ended up using even a MSD box street fire ignition box and it did not really seem to do any much different on anything such as a night and day difference on how things worked and I used a good high output coil when it was all setup with good spark plug wires etc.
 

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Mjgord51 I am still ticking but I am not getting any better health wise and am slowly falling apart more and feel my time is starting to wind down for my life but I am trying my best to keep going one day at a time. I sent a message to you.
 

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You want to match impedance of the module and the coil. This is about current flow which generates heat as the flow amount increases.

The module should have an impedance rating, this is essentially a measure of how much current it can switch without overheating. The coil has an impedance rating as well, this is an indicator of how much current it is using. Basically the lower the impedance the higher the current and as I said above more current begets more heat. That is the rub for the module.

The module more specifically the switching transistor within has a survivable heat zone which is implied by its impedance. The higher the impedance the less heat tolerant it is. We’re not necessarily talking instantaneous failure here if you match a high impedance module with a low impedance coil but this is to say the module will have a shorter life span than the correct impedance module. The module is the weak link here.

The reverse of a low impedance module to a high impedance coil is reasonably safe because the high impedance of the coil lessons the current flow through the switching transistor so it’s not heating so much.

Now one way coil builders use to get more energy out the secondary spark plug side is to reduce impedance of the coil, this makes for a nice powerful spark. But if you attach this .6 ohm coil for example to a 1.7 ohm OEM module there we’ll be heating problems with the switching transistor inside the module as it is working harder than it’s design limit.

So you want to get the module impedance spec and that of the coil to match as much as possible.

The other issue is RPM stability. This is a function of the speed at which all the components from the sensor through the module can react to the signal input. This really starts at the reluctor or timer wheel as if you get this deep you will probably find different clearances between each post and the sensor. This results in a variable signal strength between cylinders. The next step on the line is the amplifier that takes that timing signal and boosts an output voltage from the amp to actually switch the switching transistor. This is the general system architecture whether the sensing is Hall or magnetic or optical. As usual the old adage of speed costs money is as true here as in connecting rod selection.

Sweeping sensing aside there are really two types of systems induction and capacitive discharge. Basically systems not using an external box like the 6AL are induction systems and the difference between them and points is how the switching happens and the agreeable fact that transistorized switching allows the use of full B+ system voltage (12.5) on the coil instead of needing to cut that from 6 to 9 volts to extend point life to something suitable for the street.

The 6AL is a capacitive discharge where there is the timing function going on as in inductive systems but it is being used to charge and discharge a capacitor bank through the coil’s primary winding. This dumps give or take 200 volts into the coil primary winding. The sacrifice is duration of the spark, this very much is ‘wham bam, thankyou ma’am’. This system is very high RPM stable assuming the switching device in the distributor is that good; but at low RPM where mixture density is low and hard to ignite the duration is so short as to engender miss fires. The solution to this is to put a circuit in the 6AL that adds multiple sparks at low RPM’s to extend spark duration. The advantage of these systems is at high RPM where an induction system operating from 6 to 12.5 volts depending on the whether sensing is points or electronics which reaches a point in available time where the voltage is insufficient to recharge the coil’s primary winding. Keep in mind that we are creating and destroying a magnetic field in the coil. This has a feature of reactance and reluctance which greatly slows electron flow so the speed of the current inside the coil ain’t even a decent fraction of flow speed through a straight wire. A way to get around these magnetic effects in the coil is to kick it in the nuts with a lot more voltage and of course change the wave form from a shaky poorly formed sine wave to square wave.

So the induction ignition works well from start up to about 5000 RPM with OEM type parts. With hot rod versions of OEM parts 6000 to maybe 7000 is possible. With CD these need to hit the lower revs with multiple sparks to prevent miss fires, but they degrade the high RPM spark much more slowly so the RPM range is greatly extended. Below the point of needing high RPM spark the difference is in contrived testing to lead in that direction or simply in the eye of the advertising manager. Of course coil on plug gets totally around the coil recharge time issue.

Bogie
 

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I have a question Bogie as to how is a person to be able to match the control module up to the coil when a lot of the aftermarket makers of the stuff never post anything of what will match up to what and how is it you can measure them to see what will work with what? I am sure that most of the Hei distributors don't have a matched coil with a control module as there a handful of modules you can get off of ebay for the cheap and also on the coil's as well and what you get in the auto stores for oem replacements vary on quality as well with different name brands on them.

I have had good luck with the BWD stuff from Advance auto but I don't know how they compare to so called performance stuff that jegs and summit sells with a sticker stuck on them are they really any better as you can't seem to buy much quality stuff nowadays with 99 percent made in china event the big name stuff.
 

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In the case of not finding the impedance info you either need to buy the parts and test them yourself or buy on manufacturer/seller recommendations with the assumption they did the matching. This requires paying a lot of attention to the descriptions. An example from MSD is they do describe coils suitable for HEI and different coils suitable for their CD boxes. So when I read reviews I take the negatives with a grain of salt as a lot if not most guys don't understand that you can’t freely mix and match parts.

Those simply selling high output coils with no other information you can assume a couple things:
1. These are just stock coils and the advertising is just hype.
2. They are low impedance coils that will deliver a hotter spark.

In the case of number 1 you find the hyped 50,000 volt coil delivers more like 10 or 20 thousand volts and runs happily with a more or less standard HEI module.

In the case of number 2 probably the first thing you discover is the spark plug wiring isn’t up to keeping 50,000 volts inside the insulation. Then if you have points you find they burn up the contacts pretty quickly, that being spark and arc across the points that the capacitor no longer comes close to suppressing. In the case of the module it is switching currents it isn’t designed for and at some point you’ll be calling AAA or your ex-wife for a tow or a ride.

Yes most everything is made in China, the conservative, anti-communist business people left the USA for cheap Chinese labor and no pollution abatement costs. So now scientifically modern (steam engines to Mars exploration in 30 years) communist China wants the escaped free Chinese colony of Taiwan back like Hong Kong and suddenly there are supply chain problems.

Bogie
 
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