Duraspark 2

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boilermaster

Well-known member
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Feb 19, 2015
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Location
michigan
My Car
71 fastback
Ok folks,

Finally got my early (H) closed chamber heads on my 351 C.

knew it would be an improvement in compression ratio over the open chambers.

Having already had the block decked.020'' and .012'' deck clearance and .008'' to true up the heads, I knew it was gonna be tight, used the thicker fel pro head gasket to compensate a little bit.

Picked my camshaft long ago planning to be at this point.

The end results are very good thus far, runs great, no spark rattle and starts great cold (BUT)

cranked hard after heat soak.

Changed out the wimpy starter cable on my new pmgr starter last night but did not have time to test out.

Battery and charging are 100%

HERE goes the question:

How much will a duraspark 2 module retard my timing during cranking and what module to use ?

Currently running 16 degrees btdc and 36 total, not using any vacuum advance as of yet.

really wish I would brought some of the old service manuals home from the dealership back in the day.

Been back and forth between an old unilite and duraspark for distributors, not willing to discuss what module I am currently using.

Would just like some part numbers and specifications.

Would like to SEE 8 degrees or so during hot cranking.

                                      Sincerely HEI

                                      OOPS  BOILERMASTER

P.S.

Just consider this thread a module comparison test

 
I am confused by the "Early (H) closed chamber heads" comment. If by (H) you are referring to H-code 2v heads they never made those in closed chamber in the US. I am running the aussie 2v closed chamber heads on mine which were a massive improvement over the Open Chamber H code heads. I do not have any heat soak issues though. Are you running a carb spacer?

 
A Duraspark 2 module with blue grommet will provide about 5° retard. A yellow grommet module, with both stages activated, provides about 6° (4°+2°). I believe the red grommet module also has retard, but I don't have any information on them. I also believe the brown and white grommet modules aren't suitable as the timing for them were controlled by an ECU. The black and green DS 1 modules do not provide retard.

 
I am confused by the "Early (H) closed chamber heads" comment. If by (H) you are referring to H-code 2v heads they never made those in closed chamber in the US. I am running the aussie 2v closed chamber heads on mine which were a massive improvement over the Open Chamber H code heads. I do not have any heat soak issues though. Are you running a carb spacer?
Sorry 73pony,

(N)

Edelbrock dual plane with spacer, but thin gaskets.

Not saying that I have a heat soak issue after the starter cable replacement, just like to be prepared.

Totally forgot about carb spacer though.

                                      Boilermaster

 
A Duraspark 2 module with blue grommet will provide about 5° retard. A yellow grommet module, with both stages activated, provides about 6° (4°+2°). I believe the red grommet module also has retard, but I don't have any information on them. I also believe the brown and white grommet modules aren't suitable as the timing for them were controlled by an ECU. The black and green DS 1 modules do not provide retard.
Thanks Don C,

5 to 6 degrees should do enough if I still have a heat soak issue.

already wired for duraspark 2.

Are the Yellow and Red modules 4pin and 2 pin connectors also ?

 
A Duraspark 2 module with blue grommet will provide about 5° retard. A yellow grommet module, with both stages activated, provides about 6° (4°+2°). I believe the red grommet module also has retard, but I don't have any information on them. I also believe the brown and white grommet modules aren't suitable as the timing for them were controlled by an ECU. The black and green DS 1 modules do not provide retard.
Thanks Don C,

5 to 6 degrees should do enough if I still have a heat soak issue.

already wired for duraspark 2.

Are the Yellow and Red modules 4pin and 2 pin connectors also ?
I was running a red grommet on mine when I was troubleshooting some issues I had with the electrical system last year. From what I was told the red has a better "tune' per say. it was designed for California emissions and was hotter to burn more of the fuel more efficiently.

 
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From what I think I remember, the California Duraspark I (red wire grommet) provides longer dwell time allowing the coil to be saturated more. As a result the spark is able to ignite lean, and rich, mixtures better the the previous generation, Solid State Ignition, or the next generation Duraspark II. IIRC, it also requires a low resistance coil and no resistor wire in the ignition circuit. I think it also has start up timing retard but, it has been a very long time since I messed with any of these system so take what I wrote with a grain of salt. Chuck

 
The red connectors are the same as the blue. The yellow has an extra 2-wire connector which was originally connected to an altitude sensor for the second stage retard.

And, Chuck is correct, the red grommet was for California emissions and was supposed to provide hotter spark. It does have the retard function. (I did some research).

 
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Wait fellas,

theres more.

Want to run a tfi style coil with this setup.

was thinking of giving the coil the full 12 volts and the module a a ballast resistor to only the hot in run (red) on the module 2 pin connector.

anyone done this ?

what say those who know ?

                             boilermaster

 
Thanks Don C,

I appreciate your no BS answers.

remind be to put you on my Christmas card list.

                       Boilermaster

 
Wait fellas,

theres more.

Want to run a tfi style coil with this setup.

was thinking of giving the coil the full 12 volts and the module a a ballast resistor to only the hot in run (red) on the module 2 pin connector.

anyone done this ?

what say those who know ?

                             boilermaster

That is how I have one of my cars setup, it works great.
 
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