Sorry, yet another Duraspark thread

[serial car restorer]

OK, I really didn't want to start another thread, but reading through the ~10,000 posts about Duraspark hasn't helped me pin it down.

I'm a Ford noob, so I'm definitely not up on all the different colors, connectors, etc. I'm working on a '69 w/302, bone stock. So first off, I know I need a cast iron drive gear. And I seem to understand that the distributor should be matched (more or less) with the control box. But that's where things seem to break down for me.

I'm guessing that I should pick a model year (say 1974 or 1977, for example, and buy a dizzy and box for that year. (Please don't recommend I go to the scrap yard and pull it all from a single rig, the yards around here have noting that old, and are impossible to deal with.) Then since I won't have a factory harness, I'll need to snip and crimp some new connectors. (That's the simplest part for me.) And do I need a different coil? The current coil has no resistor in line, and has "Internal Resistor" printed on the body. I'd prefer to not need a resistor if possible.

So what year dizzy and box should I be looking for? Are some years better than others? Is there any reason not to match the year of the 2 parts?

 

[DirtDonk]

Except for the caps and rotors and adapter, all the Duraspark distributors for Broncos were the same. Only the modules changed.
Same three wire connector to the distributor, different connector or connectors to the rest of the system.
Same compatible gears with your 69, because rollers didn’t come in to play till much later.

You can try lots of different color modules, which I had intended to do, but essentially you need the blue grommet model because that is the one that is practically ubiquitous.
It was the last one FORD settled on, and ran until the end of the standard Dura spark system changed over.

 

[DirtDonk]

Don’t use 74 or 75, or perhaps even 76 as your go to. Order a module for a 77.

For a coil, someone else will have to jump in on that one. All the blue models use the resistor for the coil. Not sure if an internally resisted coil is sufficient to keep the module happy. But it may very well be. Most of the modules, including the blue ones, excepted 12 V to the module itself. In most cases, only the coil had the resistor wire.

For the wiring itself, there are stand-alone harnesses available from several sources, even including Painless (which is probably one of the more expensive ones) which is also quite nice and usually long enough to do the job.
Or if you want to get tricky, I would simply snip off all the much-maligned (and for good reason) Duraspark connectors, and replace them with weather pack or similar connectors.
Simplifies assembly and disassembly, and you only have to work at it a little bit in the beginning.

 

[DirtDonk]

Or you could “cheat” and get a cheap Dura spark module with cooling fins on the body, gut it, install a GM HEI module inside, wire it accordingly, and run around with 12 V powering the system.
You could even use a modern E-core coil as well, for even more power and reliability.
But it wouldn’t look as stock as a canister coil would. If that’s what you’re going for?

 

[serial car restorer]

Stock appearance is not the goal. Probably not in the top 10. Function and long-term reliability is what I'm after. If I need an external resistor, I have one that came with the Ron Francis harness I installed, and I can buy whatever coil is most appropriate for that.

It sounds like I can use almost any of the modules and ignore the connector differences, since I'll be wiring them myself anyway. So I'll look at the '77 parts as my goal.

 

[ntsqd]

One of the wiring vendors out there has a whole D-S II kit, or so I've been lead to think.

If you want easy parts replacement I suggest sticking to the OEM connectors.

Can use the points type cap and rotor if the size of the D-S II cap and rotor are a problem.

 

[nvrstuk]

I wouldn't install a Duraspark unless you use an ACTUAL Motorcraft blue module. Don't waste your time, your frustration when you become stranded when you buy a "Non-Motorcraft" Duraspark module. Gp bone yard even tho you don't like it is the way to find an OE, Motorcraft module (just order it from one of the online boneyards).

Only other option- and I am really speaking about dependability and durability - is to buy whatever other cheap crappy module you want and gut it like Paul mentioned above. But same thing, DO NOT buy some aftermarket, name brand or China made module. Genuine GM only. Accel, MSD (MySparkDisappeared) will all leave you stranded if you drive your rig. Leave your Bronco parked like most do now and non-OE might last for years but only cause it's not being used.

This is from experience and lot's of frustration dealing with guys that buy cheap crap and wonder why they don't have any spark. My .02 but actually worth .03 in this case.

What ntsqd said about connectors cause you always want to carry a spare module in your EB so you can rule out other problems when/if you have spark issues.

 

[ntsqd]

Used to be a decent JY somewhere between Bend & Redmond on the East side of 97. I think closer to Redmond. Getting there might not be so easy just yet, but it's nice over there this time of year. I bet Tumalo Falls is really something to see with the Spring melt going on right about now.

Nvrstuk touched on a pain-point, almost none of the OEM type replacement ignition modules are any good. Some are absolute carp. There's enough chinesium junk with brand names floating around out there that you can't be sure of what you've bought even with a brand name on it.
The racing parts just don't have the same kind of reliability that a real OEM part does.

"MySparkDisappeared" HAH!!! Hadn't heard that one, only CAT's "MajorlySh__tyDevice".

Do I recall correctly that someone had posted a while back about using a TFI module triggered by a D-S II distributor?

 

[DirtDonk]

I seem to remember that as well. It would be a good addition.
I wonder if finding a quality TFI module would be any harder than a quality GM HEI module though?

 

[ntsqd]

No idea, but I'm thinking that they're now much more common in the JY's than a blue strain D-S II module is.

I could be wrong, but I *think* it might have been @Broncobowsher who mentioned it.

 

[serial car restorer]

This thread on stangnet.com seems to indicate that new TFI modules (even new Motorcraft parts) aren't all that great either. And originals fail due to heat cycles (located on top of the dizzy), so a JY unit may have a questionable life expectancy.

I'll start poking around for a real Motorcraft blue Duraspark box. There's always eBay...

 

[ntsqd]

My take on these parts in particular is to source them from a junk yard. I don't buy them new.
I have bought an HEI module new, but I had a connection to get a known to be genuine GM part.

Were I going to use an HEI module I would use one of the so-called "8 pin" versions. These are used on later models with EFI, but their ECU timing controlled function is ignored if no wire is connected to that terminal. Meaning that they function like the original 4 pin modules without that wire being connected to anything. The reason for preferring them is because of the connector to the vehicle, it is a sealed MetriPack. The inductor connector is still exposed terminals, but at least one connection is sealed. I use adhesive lined heat-shrink on the inductor connections and fill the terminals with dielectric grease. That has worked to keep the corrosion to a minimum.
As I stated in a recent thread, if you use a GM HEI module it absolutely must be put on a heat-sink and you absolutely must use a thermally conductive grease to 'bed' the module on the heat-sink. Don't need a lot of the grease, but it does need to have full coverage. If you can find some, use "Arctic Silver" thermally conductive grease for this.

 

[toddz69]

I'll start poking around for a real Motorcraft blue Duraspark box. There's always eBay...

That might be about the only place to find them anymore. Things like original DS boxes aged out of junkyards decades ago.

Todd Z.

 

[serial car restorer]

Things like original DS boxes aged out of junkyards decades ago.

That's certainly true here in Western Oregon. Maybe there are some left in more rural junkyards in other parts of the country.

 

[Oldtimer]

. . . . you always want to carry a spare module in your EB so you can rule out other problems when/if you have spark issues.

If one's good, two are better, and I don't want to dig thru the glovebox when one fails.
The top one is 30+ years old.
I bought the bottom one a few years ago (from rockauto), and have been running on it with no issues, so far.

 

[ntsqd]

MSD used to make and sell a switch that allowed the operator to toggle between two different MSD boxes. I always felt like they were admitting to a problem with those......

 

[EPB72]

Used to be a decent JY somewhere between Bend & Redmond on the East side of 97. I think closer to Redmond. Getting there might not be so easy just yet, but it's nice over there this time of year. I bet Tumalo Falls is really something to see with the Spring melt going on right about now.

Nvrstuk touched on a pain-point, almost none of the OEM type replacement ignition modules are any good. Some are absolute carp. There's enough chinesium junk with brand names floating around out there that you can't be sure of what you've bought even with a brand name on it.
The racing parts just don't have the same kind of reliability that a real OEM part does.

"MySparkDisappeared" HAH!!! Hadn't heard that one, only CAT's "MajorlySh__tyDevice".

Do I recall correctly that someone had posted a while back about using a TFI module triggered by a D-S II distributor?

https://www.49ccscoot.com/manuals/FORD TFI electronic ignition.pdf heres the article on TFI and using points as a trigger

 

[serial car restorer]

I bought the bottom one a few years ago (from rockauto), and have been running on it with no issues, so far.

That bottom one looks like a Wells unit. I've always had good luck with Wells, it might make a good backup to an original DS box.

In any case, this has been really helpful. I'm putting together my wish list now:

Distributor (for 1977)
Coil (for same as above)
Ballast resistor (have one already)
Ignition module, blue insulator (for 1977 also)

Wiring—rather than slice and dice new-to-me module wiring, I'd prefer to use the factory connectors (even though they aren't well liked by some) to simplify parts replacement away from home. It'd be nice to not have to cut and splice connectors to be able to replace a module on the fly with one picked up off the shelf somewhere. Three connectors are needed. They are:

3 pin female at the distributor
4 pin female at the module
2 pin female at module for power

Edit - The first two are easy to find. The 2 pin female has proven more elusive. Any suggestions on that one? Or will I need to find one from a scrap wiring harness somewhere?

Ok, after a bit more checking and comparing to the Painless Duraspark harness, it looks like the 4 pin and 2 pin are the ones I have found so far, but not the 3 pin female at the distributor end of the harness. So that's the one I'm hunting for now.

 

[gr8scott]

@serial car restorer

From this thread:

Duraspark II which wire to delete? HARNESS AND NEW BOX DONE

I found out I do not need to run a ballast resistor, with my MSD Blaster ss coil. I can run full 12 volts .I'm in the process of changing my ignition to the blue grommet box, so I'm going to make or buy a new harness, so in this diagram, which wirers would I delete if any or just eliminate the...

classicbroncos.com

 

[ntsqd]

As I recall the 3 pin female at the dist. is connected to the pick-up coil assembly. Shouldn't need that one.

I much prefer to use the later model's E-core coils. I ran one for years on the Ranchero (sold it that way) without a resistor of any sort. Unlike points systems, the module controls the current thru the coil so a resistor is not needed.