Duraspark wire identification

[Viperwolf1]

I think we talked about this a few years ago Phil, but if not for start-retard, then what is the purpose of a wire that connects to the start circuit?

Why does it need to know when the engine is cranking, vs just getting a key-on signal from the ignition switch? Is there some need for more current handling capacity of two wires for a hotter spark? Since it's not on a resistor (for most Duraspark applications anyway), and it's not the source of the spark like the coil is, and can use extra voltage during the cranking, it seems a waste.
Some type of "dwell control" for enhanced coil energy production for an easier start?

Why all the trouble and expense to connect a second wire if not to do something really cool and mysterious? ;D

Paul

It may increase the dwell time during cranking to get a hotter spark.

 

[Jdgephar]

I believe there are some errors in that table Viper. It lists the blue grommet Duraspark II as being able to turn off the coil primary. That is a feature of the California only Red grommet Duraspark 1, and that's because it's the only one with a circuit to adjust the dwell (and turn off the coil voltage). The other modules don't have the dwell adjust circuit, and no way to turn off the coil if you leave the key on run without the engine running. This is what I've read, anyway. There are also numerous reports and tests confirming the start ignition retard with the blue grommet Duraspark II. It's not as much retard as the white grommet box, but still there.

Now, maybe what I'm reading is a bunch of internet whoo-ey. I'm going to check mine for a timing retard today after work. I've got three or four of them I can try. Maybe it's just a feature that was included in all of the aftermarket replacement units?

Sorry to keep this going in the op's thread. I would just like to know the facts. Maybe we can start a new thread on the different Duraspark setups and have people test and report their findings?

http://en.wikipedia.org/wiki/Duraspark
http://www.crankshaftcoalition.com/wiki/Duraspark_ignition
http://bzerob2.wordpress.com/2012/12/04/more-duraspark-notes-3/
http://www.webring.org/l/rd?ring=cj;id=1;url=http%3A%2F%2Fwebspace.webring.com%2Fpeople%2Fdg%2Fgeer_hed%2Fcj_ignmod.html

 

[DirtDonk]

I agree it would be a cool thing to test. Hope you can take the time to do it.
One of your links actually listed the different degree ratings, which was interesting to see. I wonder if they actually tested, or like so many others, just used what they'd heard somewhere. First time I've ever seen that though.
At least it seems consistent in that the one module that most others claim to be the one doing most of the retarding was the one with the most retard at 14 degrees. That's quite a lot actually. Even the supposedly 4 degrees of the Blue boxes would be reasonable for our purposes.

The second link I think (looked like a Wikipedia page but with a different name) looked like it was written with some info from a Ford book I've got that covers only the Duraspark ignition systems. Don't have it in front of me (been looking since this thread came up actually), but some of the paragraphs looked familiar.

We'll see though, hopefully.
And hopefully too, Travis (the OP) doesn't mind this little segué sideshow direction we've taken! ;D
Like you said though, with so many sources of information, it's just cool to know this stuff for sure.

Paul

 

[Viperwolf1]

I believe there are some errors in that table Viper. It lists the blue grommet Duraspark II as being able to turn off the coil primary. That is a feature of the California only Red grommet Duraspark 1, and that's because it's the only one with a circuit to adjust the dwell (and turn off the coil voltage).

Opening the coil primary circuit is what causes the magnetic field of the coil to collapse into the secondary circuit and fire the plugs so they all do that. I'm also interested in seeing your test results.

 

[Jdgephar]

I checked the timing last night with and without 12V applied to pin 5 (white wire from the Duraspark box on mine). I have two blue grommet modules that I tried. Both gave me about 3 degrees of timing retard when the 12V was applied.

Opening the coil primary circuit is what causes the magnetic field of the coil to collapse into the secondary circuit and fire the plugs so they all do that.

I agree. There's just many references around the web to be careful with any of the boxes that are not the red grommet, since they supposedly do not turn off the coil if the engine does not start.

At least it seems consistent in that the one module that most others claim to be the one doing most of the retarding was the one with the most retard at 14 degrees. That's quite a lot actually.

From what I read, that's a turbo application, so I can see the use for that amount of timing retard under full boost.

 

[DirtDonk]

I had a thought yesterday (happens occasionally) about dwell. Isn't a change in dwell automatically going to change the timing slightly anyway? I mean, in an electronic device like this, might they not use dwell time to retard their timing too?

We were talking about dwell in regards to spark energy at the output of the coil, but if I remember my points ignitions, when you change the gap/dwell, you change the timing.
I don't know the exact relationship anymore, since I haven't adjusted many sets of points lately. But it makes sense, so I was wondering what you guys thought about that.

Thanks for checking that jd. Good info.

Paul

 

[Viperwolf1]

With a mechanical switch, like points, changing the gap/dwell affects both the closing (primary charging) and opening (primary discharging) times of the points. That does affect the timing. With electronic ignition you can't really do much to change the primary discharging time. It happens when or shortly after the reluctor is aligned to the coil. You can make the primary charging time happen sooner though. Remember with points the coil fires when the points first open then you have to wait until they close again before you can start charging the coil (exception is dual point distributors which take advantage of this). With electronic you can start charging the coil right after it fires, no waiting period. So you can change the dwell with electronic ign without affecting the timing.

 

[Bronco1294]

Hey all. I’m installing pertronix distributor and fitech and having wiring issue. I have ace tech harness. I assume all 3 wires orininally going to distributor are useless now. Red goes to ign pwr, green to coil, and white to start?

 

[DirtDonk]

Hey there. What year is your Bronco, and what is an Ace Tech harness? I could search I'm sure, but a link would help.
In fact, just to be sure we're all on the same page, what exact model Pertronix distributor do you have?

Are the Red, Green and White wires from the body harness, or from the FiTech setup?
Or are they from the old ignition module harness? Since this is a Dura Spark thread, presumably you have a '74 or later EB that had the Dura Spark setup. But it's good to know this stuff for sure right up front.

And boy, talk about resurrecting an old thread! Now I'm going to have to re-read it just to catch up again! Well, just for fun to see what we were up to four years ago anyway.

But start with the details and that should get things rolling at least.

Paul

 

[Rustytruck]

I dont see where travis ever identifyed what color his module was.