Can you blow an HEI module?

[Bonnewagon]

you can use a 5 pin HEI module and have a switchable 10 degrees of timing retard.

So are you saying that when the CCC detects detonation it informs the module and that retards the timing? I know the 1980 Turbo TA just used a detonation sensor at the rear of the 301 block. That went to a module located under the console. Pretty much a stand-alone anti-detonation system. Do you know how exactly that works, wire by wire? Is it an automatic 10 degrees of retard or is it variable?

 

[Wageslave]

So are you saying that when the CCC detects detonation it informs the module and that retards the timing? I know the 1980 Turbo TA just used a detonation sensor at the rear of the 301 block. That went to a module located under the console. Pretty much a stand-alone anti-detonation system. Do you know how exactly that works, wire by wire? Is it an automatic 10 degrees of retard or is it variable?

I"ll cut and paste some info I found on it:

The 5-pin module came in 3 versions, they differ in type of input signal to retard the ignition. All the 5-pin modules are used with distributors having conventional centrifugal and vacuum advance mechanisms.
1. HEI/EMR Electonic Module Retard, this is the one described here, it originally used various input signals to an electronic controller, that provided a ground signal to activate the retard mechanism.
2. HEI/ESC Electronic Spark Control, uses knock sensor and an electronic controller to provide a voltage signal to the module to activate the retard mechanism.
3. HEI/ESS Electronic Spark Selection, uses signals from pressure or vacuum, temperature and distributor into an electronic controller to provide a voltage signal to the module to activate the retard mechanism.

#1 has a small R terminal and will pull timing when grounded. It can be used through a relay that pulls while the key is in the crank position to ground that terminal to make starting easier, or it can be used through a toggle switch to give always on retard if you are set up for premium or race gas and need to run regular gas to get home. They can also be used through a pressure switch to give retard under boost. This modules original application is a 1980 Olds 260 and can be bought new as a Duralast DR137.

#2 and 3 i have not personally messed with, but I believe they work on a similar principle, but with +5v or +12v applied to trigger instead of a grounding input.

As far as I know, all versions are on or off, and are not variable from 0-10 degrees.

Another fun fact though, there are small cap 8 pin modules that have a built in advance curve that don't need mechanical or vacuum advance to work. Given it's only 22ish degrees, but it might make the lives of the locked distributor drag race guys a lot better. I believe they are known as Mercruiser's Thunderbolt ignition system.

Info:
8-pin module with built in advance curve
Not well known on the automotive scene, Delco also sold a marine HEI distributor kit to upgrade older boat engines to electronic ignition. The Delco Voyager Marine Distributor Ignition System was made for 4 cyl, V6 and V8 engines, and reportedly used the same module in all adaptations. These marine kits use a different 8-pin module, that provides a built-in advance timing curve, and works without using an ECM. The marine kit was delivered with a distributor without any mechanical or vacuum advance. The module could be an interesting alternative used with a Lean Burn distributor on a race engine. But there is of course no problem to use them with any distributor...

An 8-pin module for a car will not work, they have an externally adjusted advance curve, HEI/EST - Electronic Spark Timing provided by an engine management unit.

I have seen claims for 20-22° advance built into the marine Delco module, but in the curve I found, it starts on 11° and give 22° total advance. It may be incorrect, and it must be investigated further, because the engines the kit was intended for, all like around 30° total advance. I would guess that the curve shown is for a SBC V8.

RPMS/Advance
700/11
750/12.5
800/13
1000/15
1250/16
1500/16.5
1750/17.5
2000/18.5
2250/19.5
2500/20.5
2750/21.5
2800/22

There is also the Mercruiser Thunderbolt Ignition system, that has the same functionality. There are several ignition mudules available. See this site for info:
http://wolfiesenterprises.com/Ignition _ Distributor Parts.htm

Here are advance curves for the ignition modules used in Thunderbolt TBIV and TBV systems (for carburetted engines):

http://www.mtboats.com/mercuryignitionadvancemodules.html

 

[Bonnewagon]

The 5-pin module came in 3 versions, they differ in type of input signal to retard the ignition. All the 5-pin modules are used with distributors having conventional centrifugal and vacuum advance mechanisms.
1. HEI/EMR Electonic Module Retard, this is the one described here, it originally used various input signals to an electronic controller, that provided a ground signal to activate the retard mechanism.

#1 has a small R terminal and will pull timing when grounded.

This modules original application is a 1980 Olds 260 and can be bought new as a Duralast DR137.

This info is golden. THANKYOU!!!!!

 

[pagrunt]

For stock, I've never had an issue with a coil in cap. ACDelco on the coil, or nothing on those for me, however. Same with many of the electronic components. I don't buy all that aftermarket stuff, so I'm a poor source for reference on that. I can say that if you go with Standard parts, or Borg Warner on the sensors/ignition parts, many times they're as good as the GM stuff as they made many of the components over the years for GM anyway. I'd shy away from Bosch, however. I've had nothing but bad luck.

Back in the day when Mallory was still running it's full line (like before MSD took them over) I would run nothing but their HEI parts. Never had any issues. Never had too much luck with Accel parts. I still have my coils & using the one I originally put on the 305 when it went in the Monte 20+ years ago. Back in the parts jocky days I would find GM marked parts in Borg Warner boxes at the stores.