Okay here I go again! Lol so I guess I finally made up mind on what ignition I'm going to use till I have enough money to buy my DUI ignition setup!

So has anybody else done this mod I know JimRebel has I think he the one who suggested I do this mod!! But has anyone else done this mod?? have you seen any thing different like the way the motor runs and power gains!

 

Loser Index

Info on using the HEI module can be found there.

 

thanks harte! by any chance you yourself havent done this mod?


thanks again,

FordBoy

 

I've never done this mod on a Ford, but I have a Mazda rotary engine that is running with 3 X GM HEI modules/coils. Kinda wild and crazy, just like all things rotary engine related.....


If you look close, you can see the 3 GM HEI's mounted on the far strut tower.

A few tips. There's 2 plastic "pins" on the back of the HEI module that MUST be removed so it can sit flat against some type of metal. Make sure the module is mounted *firmly* to a piece of metal thick enough to absorb heat. And be sure to use the thermal paste that *should* come with the HEI module.
I have changed my mounting plate from that pic. It is now a piece of 3/16" polished stainless plate, and I put artic silver 5 (computer geek stuff) between the HEI's and the plate.
The original plate was thinner sheet metal, and all 3 modules died from heat. Heat is the number 1 killer of the GM HEI module, especially the cheapo chineese made ones......

 

*whistles* that a nice looking setup you got there dude! Why so many HEI modules? Is it just in case one of them fails? I plan on getting a pertonix or accel HEI modules!

 

First off there is nothing to gain with a DS2 conversion if your EEC IV system is working as it should. If it is not working and thus running in fixed base timing, open loop, limp home mode, you will gain power, performance and MPG if you switch to DS2 distributor because you will get timing advance again.

It might not be cost effective to repair your EEC IV computer controlled ignition system, so if you don’t have to do emission testing/inspecting in your state you would have the option to convert to a DS2 distributor which has mechanical and vacuum advance. After installing the distributor you have some choices. In a perfect world you would just swing by the junk yard and get the stuff you need, but it seems to be harder and harder to find an 80-83 I6 in the junk hard to get a DS2 harness to convert an 84-86 F150 with a 4.9 engine.

I used a GM HEI 4 pin module because I wanted to use the newer style square coil which was currently mounted to my engine and is better than the older round coils, but to be fair the older round coils are good enough and work well with a duraspark 2 ignition module. I got some used 4 pin modules and a short piece of the mating harness to match up with the distributor plug for next to nothing at the junk yard. I mounted the 4 pin modules to a used computer CPU aluminum heat sink. At that point just a few more connection and I was up and running. The only real cost was an O/H dist from Napa.

The advantages to a GM 4 pin HEI module are…
1 You can run a higher coil positive voltage with a square coil and thus potential higher coil output to the plugs.
2 You can wire this into your current engine harness
3 No current flow with KEY ON in the coil primary circuit.
Disadvantages to a GM 4 pin HEI module are…
1 Looks like it is an add on and does not look stock
2 Does not have a 2 deg spark retard while cranking

Issue with a DS2 distributor and stock DS2 system conversion.
1 84-86 trucks have a wire which bypass the resistor wire
2 Almost impossible to find a good engine harness

The bypass wire which parallels the resistor wire in EEC IV ignition system could result in higher than normal voltage applied to the coil and thus higher current flow which causes higher heat in the coil and DS2 module. While you can just plug it all together and it will work, the higher heat will cause lower reliability of the coil and DS2 ignition module. Using a square coil with a DS2 module make this even worse as it has a lower primary resistance and thus higher yet current flow. On my truck the bypass wire did not bypass the whole resistor wire and thus still dropped about 3-4 volts. After a 84-86 DS2 conversion with stock ford parts it is very important to check coil positive voltage at idle to be sure the coil is getting the proper voltage.
Jim

 

Good writeup Jim but that part isn't exactly right. You gain a simpler ignition system and the ability to swap to better intake/exhaust. Mine is "almost" back to running right but sure wish there was a way to take advantage of better carb/intake/exhaust and keep it smog legal but haven't found one.

 

Great write up Jim!!! Thanks for the helpful info hope to be doing this mod in the next couple weeks i hope if all is well! Oh yeah where did you mount your HEI Module Jim?? I took a look under my hood today i was figuring out where to put it.

 

 

*WARNING: Rotary engine tech. Read at your own risk...... (we all know they run on black magic)

Actually, 2 of the modules and coils fire a single plug, and are triggered by a single magnetic pickup in the dist. These fire at the same time, on the "Leading" plugs, every 180* of engine rotation.
The 3rd module and coil are triggered by a 2nd magnetic pickup inside the dist, and fire the "Trailing" plugs thru the dist, each plug only fires once per engine revolution.
Rather complex to explain, but rotary engines have 2 ignition systems, firing 2 sets of plugs, at different times during the power cycle. Early engines used 2 dist's, and later the dual systems were configured into a single dist. When the 2nd generation of EFI entered the equation, the ECU was used to trigger the coils, firing the plugs in the same manner as my custom setup does. This car was gen 1 EFI, which used the older single dist/dual system, but has been highly modded, as the Edelbrock carb and plate full of GM HEI modules clearly show......

When the 2 "Leading" modules burned up, I did swap plug wires around and make a timing adjustment, in order to run the engine on the leading plugs, fired by the trailing ignition system. That module lasted just long enough to get it back to the shop, before going up in smoke. Hence, the reworked mounting plate.

 

That may be the place I'm in. Square coil and all. What is the correct coil positive voltage at idle? If it's 12v, that means it needs a ballast resistor? Sure don't want to fry the module...

 

OOOOOhhhhh okay i think i get it, i got kinda confused but i think i know what your talking bout.

 

The voltage should be lower then 10 volts to be on the safe side.
You can also add washers under the DS2 module to help in cooling it.

To get a handle on what you have check some voltages...
Key on, not running
Battery volts
coil pos and neg, with the neg voltmeter lead on the battery neg or a good engine ground.
Coil pos while at idle, and battery volts for a ref point

Does the DS2 module feel hot after it has been on the road for a while.

The square coil is not an issue as it can take full ALT voltage.
Jim

 

Groovy, at idle the coil + is ~8.7v and coil - is ~8v and battery voltage is 14.45. So no worries then?

 

Yes the numbers look good, no worries.