I have a Duraspark distributor hooked to a GM ignition module. I know this set up requires a specific coil. What coil works? I bought a generic chrome coil from Jeg's and it didn't last long. It would idle for about 10 minutes then die. I tried another new Delco 1906 module and it was the same. Changed carbs, same thing. Put in the stock points coil and it ran good. Swaped back to the Jeg's coil, problem came back. I put the stock Ford coil circa 1971 and it ran good.
I let it idle for about 1/2 hour while I was charging the A/C, tracing heater A/C cable problems etc and it died again. The stock Ford points coil was hot. After it cooled down, it ran again.
I know I need a coil. Which coil should I get that will last?
I do not have an ignition resistor nor do I have an resistance wire going to the module.
Please let me know what coil you guys use that doesn't burn out or get hot and die.
Thanks.
Danford1

 

Wire in a ballast resistor for under $5 or buy a coil specifically marked no resistor needed/internal resistor. There are a few.

 

Ever think about using a duraspark box? Apparently what you are trying to do is not working. I believe I have seen on the web people mixing and matching ignition components, so you will have to depend on them for what works for those particular setups. I don't know why they bother though, the Ford system works ok for most people.

 

OK, I determined I DO need an ignition resistor. I've played with a few coils and it will run with an old yellow top Ford coil. I did research and found guys use a MSD Blaster 2 or 3 coil with the GM module. I bought a Blaster 3 because it had the post type coil wire hook up which I want. Measures 0.9 ohms on the primary side.
The car will not idle with the Blaster coil. I have some resistors and if I use one, it runs fine. SO I know I need a resistor.
I have 2 and they are different. One measures 1.9 ohms and when installed and running I have 9.8 - 10.0 volts between the positive coil and ground.
The other one measures 1.5 ohms and reads 11.4 volts from positive coil to ground while running.
Which one should I use or is there some other one I should get?

Thanks.
Danford1

 

If you are running a Ford with the stock Motorcraft Duraspark distrubutor, you need the correct Motorcraft ignition coil and Motorcraft ignition module.

Seriously, what's the point of all this cross-breeding? Why would you want to cut up your factory wiring to trade one ignition module for another? It's not like the GM module is an "improvement" over the Ford module. In fact, the Ford Motorcraft ignition module has the "start/retard" function that the GM and aftermarket doesn't. This feature actually retards your timing a few degrees at startup for quicker starts and allows you to run more timing.

You have learned the same lesson I have about aftermarket parts. Most of the aftermarket parts, no matter how pretty and shiny they are, simply do not last. MOTORCRAFT parts cost a little more, but they last. Also keep in mind you are mixing and matching two very different ignition systems, and that may very well be compromising your parts. I strongly suggest you toss all that GM and aftermarket junk out and simply do it the way the Ford engineers originally designed it. After all, the Duraspark ignition was good enough that Ford used it across the board on all of their vehicles for over ten years, and even AMC used it for a while in the 1980s.

Unless you are actually racing your truck or are consistently running up to 5000+ RPM, you will *not* gain any "improvement" over a correctly functioning Duraspark ignition system!

 

I'm going by my feeble memory, but did you heat sink the GM module? I've never used one, but remember they are required and heat does funny things to electronics. I've seen the conversion instructions somewhere and I'll see if I can find them. Stock DSI was 1.4 ohm, my DSII blue module wiring say's 1.1 ohm. Course, all bets are off with the GM module.

 

The HEI module does need a heat sink. As for a coil, get one of the external HEI or use a Ford TFI coil, neither of these require a ballast resistor and are the correct resistance for the module. I also wonder why you would want to use a GM ignition system? A good DurasparkII system is extremely reliable, once I got rid of the cheap aftermarket module on mine in 1996 I never had any more problems.

 

I just switched back from the gm HEI setup. Too many problems. A link to the Dirt cheap Ignition is under the post "Coil problems......I think" if you need to refer to it. But what can I say, I just hooked all the Duraspark stuff back up and I got a whole lotta no spark to show for it.