I'm looking to replace the distributor in my '85 4.9l i6 fl50 with an hei distributor. I heard a lot of good things about them with simplifying the system and more reliable. But I don't understand how to wire it up. Haven't worked any wiring before. I've looked through threads and most people talk about how they got them but not how the installation went. And tips and helpful directions or specific videos on this particular truck would be helpful.

 

The HEI being more reliable than the factory Dura Spark is a myth. The only real advantage the HEI has is simple hook up.

 

And there you go how to wire
HEI need a full 12 volts (10 gauge wire) to work and that is only 1 wire hook up.
Now the issue is you don't have a full 12 volts (10 gauge wire) to power the HEI unit so you have to wire in a relay.
You would have a full 12 volts in & out of the relay to power the HEI and use the lower voltage wire to trigger the relay.


Now I cant tell you hook this wire to so n so and that wire to here as I don't know with out looking the trucks wiring up and how the relay connections work.


If you do a Youtube search for wiring a relay that should get that part done and you would just need to find the trigger wire.
Dave ----

 

That's the "Right On" man.

 

Don't tell anyone I used a GM part but a DurasparkII with a HEI module (well hidden) and a 90s efi coild is easy to wire up and every bit as good as an HEI and far superior to the cheap HEI's now being sold. If you MUST have an HEI, get a Davis Unified, the guys who started the ugly trend.

Here is a great tutorial and simple diagram on the GM module install. But the hot efi coil is what you want. A Ford module can't pull the big coil, so I'm told. I modified a remote TFI heat sink and kept it on the fender area. Some guys go to the trouble to gut a DurasparkII module and hide it inside. I even knew one guy who used an aluminum Briggs and Stratton head for a heat sink.

How To Convert A Ford Or Chrysler Ignition To GM HEI - Car Craft - Hot Rod Network

 

The Dura spark module can handle the Ford TFI coil as long as the ballast resistor is left in place. I've ran this set up for over 10 years with no issues.

 

Sorry Chief, but replacing the DSII module with an HEI module and TFI coil will gain you absolutely nothing on a stock or even modified engine.

WHY are so many people are doing this?



"Ugly" is right. That GM HEI distributor is the UGLIEST monstrosity of a distributor I have ever seen. At least it is hidden at the back of the engine in a GM. But in Fords, that HUGE distributor will be the centerpiece of the entire engine.

But if you must, I agree that the DUI is the best one to get.


I beg to differ.

I tried using my original TFI coil when I did the Duraspark II conversion on my own truck (feedback carburetor with TFI ignition and EEC-IV), and it burned up TWO BRAND NEW ignition modules within a week! And yes, I was using the stock ballast resistor wire. An Advance Auto parts $25 special lasted one day, and a $65 Motorcraft module lasted the rest of the week before it too, burned up.

Before I replaced the ignition module for the third time, I replaced the TFI coil with the proper DSII canister-style coil and nothing else was done. I haven't had an ignition problem since. That was 10 years ago.

I went through all that trouble, and I couldn't feel a bit of difference between the TFI coil and Duraspark coil at all.

 

I had a few coils go bad in HEI distributors during my Chevy daze.....before people had cell phones..... sometimes at odd hours......in the dark.....not so nice neighborhoods.....

 

Well, I have to disagree and even you yourself said you burned up stock ignition modules. The gain over a cannister coil is a hotter spark. The gain with a gm module is that it can take the hotter coil, even though some say it's not necessary. Also the gm module varies dwell, which the duraspark 2 does not. All in all, I ran that set up on a 300 for years. It always popped off on the first crank no matter how cold it was out and performed flawlessly. I personally feel the use of the 50,000 volt coil (similar to an HEI coil rating) is just better than the can that does half that at best. But then I run a stock coil and points on several of my old Fords and have few complaints on that system either.

 

The ones that say it is "not necessary" are right. You won't ever use that hotter spark. That is why you won't notice a bit of difference. As I said, I used both coils, and I couldn't tell a bit of difference. None.

If both of these systems were brand new and properly functioning, the GM HEI will gain *nothing* over the Motorcraft DuraSpark II ignition.


Well, the DSII module retards the ignition timing at startup for quicker, easier starts - something the HEI does not. This allows you to run higher initial timing for better performance. I don't know if it varies dwell or not, but my Duraspark II always pops off the engine on the first crank no matter how cold it is outside as well. In fact, my truck actually starts up faster than any other vehicle I have ever owned with EFI. It's incredible - I can't get off the starter fast enough! And, mine performs flawlessly as well.

So, what's the point?


If you "feel" it is "just better," than keep running it. I don't think there is anything wrong with it, I just don't see the point in replacing one ignition module for another, in order to use one ignition coil over another, for a hotter spark you can't use.

 

Well that's unusual cause I have done that swap more times than I can count Dozens of them back in the day. And never had an issue with it not once. But I always used genuine Ford TFI coils and not aftermarket ones.

Since you converted from EEC IV to dura spark something else must have be at play that was over loading the ignition box with the TFI coil.

The Stock Dura Spark ignition systems can handle the TFI coils with no issues

Where the TFI coils out perform the stock coils is in situations of peak ignition demand this is most notable in subzero cold starts.
At -30 the difference between the stock dura spark coil and the TFI coil at start and during and warm up is huge.

 

WTF is with you guys. It's like you have to dis what other people like to make yourselves feel better or what? I'm frankly getting a little tired of having any of my experiences and opinions line item invalidated or having to defend them. We all have different preferences and have tried different things we liked, whether it suited you or not. Can't we just share our own preferences and experiences with out you guys needing to disprove it to make yourselves look like the smart guy. Dragging someone else down is not the way to elevate yourselves.
If the industry didn't feel a need for hotter coils, they surely would not have changed them just to be changing whether you can notice a difference or not.
And I'm pretty sure the 30 below winter days here are a little colder than SC so maybe, just maybe starting in REAL winter is enhanced with the hotter spark.

 

I though you can have a coil that puts out 100K volts but if the system only takes say 30K then you paid for 70K you are not using.

Now between the 2 coils you guys are talking about the only way I see you can say what one is better is to measure the out put of both to make sure they both put out the same amount but the BIG thing I think is the saturation rate of each coil.
If one take longer that the other then it will not have the needed amount of volts to fire be it winter or summer, idle or 6000 RPM where it would need it the most.


The other thing I see for saturation rate is the control box.
I think that is the only reason why you would want to run the GM module over the DS unit.
IIRC you can get Hi Po GM & Chry (silver box) modules and they change the dwell to help the coil build up power. I don't remember ever seeing a Hi Po for the Ford DS unit?


Anyone read Dr. Jacobs book on electronic ign.? My book is back when he first started out, before he sold off to what they are now.
http://www.jacobselectronics.com.au/index.htm
He had all this information on how to use any box/coil/dist. you wanted to make a system work. He also listed what he felt was best (at the time) to use and why.
Dave ----

 

While some considered Jacobs to be very revolutionary in his approach to ignition system design ( his book is a major puff piece for his stuff), my personal opinion is...so what. His systems were nothing more than a digital version of all the same old capacitve discharge boxes that the aftermarket has been doing since forever. While his coils were blingy, in actual use they had no advantage over any other high turn ratio/high potential output coil on the market. Plus the jacobs track record for both reliability and customer service was abysmal to put it mildly. Today they are nothing more than a disappearing brand with in the prestolite group.

The Ford TFI coil's have a much faster saturation rate compare to the old bar core coils, and saturation rate is really only an issue in MSD type ignitions.

E Core coils such as the Ford TFI coil are not new by any stretch and have been kicking around since the 60' They are far more efficient than the old bar core conventional coils.

The demands on the ignition system are not static, so can you ever too much available spark energy ? Well given the option of having it and not needing it or needing and not having it and having a miss stumble hard start or rough running cause I don't have it, I'd rather be looking at it, than looking for it.

 

Okay, so I was wrong.


I went back and looked at my notes from 10 years ago when I replaced the TFI ignition and EEC-IV computer with the DuraSpark II ignition. It seems I forgot an important detail:

1. - My first attempt of the DSII conversion consisted of a cheap, Advance Auto parts $25 ignition module and my stock TFI E-Core coil. I did not use a ballast resistor and the ignition module burned up within 1 day.

2. - The second time I used a $65 MOTORCRAFT ignition module and my stock TFI E-Core coil. Again, I did not use a ballast resistor and that ignition module lasted about a week before it too, burned up. (That goes to show you how much better the Motorcraft ignition modules are.)

3. - Before I replaced the ignition module for the third time with another MOTORCRAFT unit, I decided not to take any more chances on a "hybrid" ignition system and so I replaced the TFI E-Core coil with the proper MOTORCRAFT DuraSpark canister-style coil and plugged in the stock resistor wire. It started right up and I haven't had an ignition problem since. That was 10 years ago.


But I will say this again: I went through all that trouble, and I couldn't feel any performance difference at all between the TFI coil and DuraSpark coil.


That *must* have been why I kept burning up ignition modules. It looks like you are correct!


I have no idea if you are right or not, as I live in the Deep South where temperatures don't get that low. But since you were right about the ballast resistor wire, you are probably right again.

Last thoughts:
My third (and final) attempt of running the DuraSpark II ignition system was used as Ford engineers intended: MOTORCRAFT ignition module, ballast resistor wire in place, and the correct MOTORCRAFT DuraSpark coil. This combination gave me the best start AND idle, believe it or not.