How much voltage does the Duraspark coil put out?  Dave

SE Wis

Rob, Since your engines horsepower peaked at 5600, start with a rev limit around 6000 and play with it probably between 6000 and 6500 until you get your shifting figured out for racing.

Dave, No idea what the Duraspark coil puts out, but if you want something better, it doesn't matter, because you do not want a full Duraspark setup.  You want to use the trigger in the distributor and an aftermarket box, coil, and wires (MSD, Mallory, Performance Distributors, etc.).



Lawrenceville, GA

I have experienced a problem with the old style ( short neck ) Flame Thrower coil.  However the "New improved" version has a longer neck no more spark arch from coil wire to 12 v post.

I would have a misfire that was noticeable at 1500 RPM.  New coil no spark arch no problems.


Jim

  Jim Rowe Elkhorn, NE

Dave V -
The coil voltage rating is that of the coil insulation - not the actual delivery of an inductive spark system. On induction - nonsupercharged - it only takes about 10,000 volts to fire a plug in a "compressed" cylinder. Having a coil with a 50,000 volt insulation rating is nice - has a "factor of safety" of 5. But a coil with a 35,000 or 40,000 volt rating would probably work just as well. at delivering the 10,000 volts. 

The spark energy is a Volts x Amps sort of thing - and if you say all of the induction ignitions are at 10,000 Volts - then the Amps will be based on the summed resistance of the coil primary and ballast resistance. On the factory Duraspark II set-up, the coil primary is about 1.2 Ohms and the resistance wire from the ignition is about 1.4 for a sum of 2.6 total Ohms. They operate (factory Duraspark controller) at the same fixed dwell as the single point distributor - so the potential increase of performance is pretty much limited to what Amps you get at those Ohms versus the old coil and ballast resistor. This is only an approximate description - but....... it helps a bit with understanding the pricinple.

These later model control systems with amperage controls (Pertronix III and the HEI type) - have coils of only .5 Ohms (no ballast resistor) - and a variable dwell control (electronic switch) that leaves them "ON" to just safely short of meltdown. They maximize Amps at every rpm - not just a fixed delivery at any speed.  

Hope this helps a bit .......



 
 Steve Metzger       Tucson, Arizona

Steve   Sorry I havn't replied sooner but I was at a car show all weekend. I searched and found your procedure for setting up your own HEI system with a Ford Duraspark trigger, GM 4 pin HEI controller and GM V6 .45 ohm coil. I would like to keep the car a little more original looking so would my Pertronix Flamethrower .6 ohm coil work ok with your other trigger and controller?  Dave

SE Wis

Dave,
You're not likely to get anything better than a Pertronix II or III, and maybe even I with oem ignition parts or any combination of oem parts.  The major benefit to Steve's system is that you can get replacement parts at any autoparts store, or out of any junkyard.
If you want to maintain a stock look, then Pertronix or a similar points replacement module is your best bet, which you already have and I would change nothing.  I certainly would not spend additional money for something that may only be as good and does still require some sort of fabricated mount or box for the module that will further detract from a stock look.



Lawrenceville, GA

Setting the rev limiter on the Petronix is very simple. First off it is factory set at 5500, so if you don't want to go past that, just leave it alone (trust me, it works!!!  LOL). To cahnge it however, you can do it on a bench with a 9 volt battery attached or once it is installed in the car, bay simply turning the adjustment screw on the module and counting the blinks. (  I copied the procedure below)

REV-LIMITER SETTING PROCEDURE
Remove distributor cap and rotor. 1.
Turn the ignition key to the ‘ON’ position. Do not try starting the engine.2.
Turn the Rev-Limit dial clockwise until it stops. Turn the dial counterclockwise until it 3. stops. A slow blinking of the LED indicates that the setting procedure has been initialized and that the Rev-Limit can be set.
Turning the dial clockwise sets the Rev-Limit. After turning the dial, pause and watch 4. the LED for verification of the Rev-Limit setting. Long flashes indicate 1000 RPM’s and short flashes indicate 100 RPM’s. For example, 6 long flashes followed by 2 short flashes means the Rev-Limit is 6200 RPM’s. Continue turning the Rev-Limit dial until the desired Rev-Limit is reached.
NOTE: Leaving the Rev-Limit dial in the full counterclockwise position disables the Rev-Limiter.
Let the LED sequence thru at least three complete cycles. This verifies the correct set5. ting and prepares the unit for permanent storage of the Rev-Limit.
Turn the ignition key off, this signifies to the Ignitor III that the Rev-Limit procedure is 6. complete. Note: The Ignition key MUST be turned off or the engine will not start.
Your rev limit is now set and will not change until you go through this procedure again. 7.
Re-install cap and rotor.8.
NOTE: Setting the rev limit may be done effectively and easily on a bench or table. Connect the module to a 9-volt battery as shown in figure 2. Then follow the setting procedure outlined above.



I love the smell of burning rubber in the morning!

After reading all this and doing some additional research I plan to replace my old original Pertronix, coil, and factory resistor with the Pertronix III, coil, and remove the factory resistor. Plan to keep the old setup in the trunk as a spare just in case of a failure. I was planning on just adding a MSD 6 AL box to get the rev limiter. This will give me the same thing basically and I can keep the stock appearance. As always, great information here. Now if I can just find the time to get the engine and transmission back in the car.   

Make sure to set your timing after you install the Petronix III. Not sure if it was due to the positioning of the sensor on the module (only fits one way) or the fact my old Petronix was going the way of the dinosaur, but originally had my timing set to a full 36 deg. (without vacuum advance) on the dyno. Once I installed the new Petronix, I was now at a full 50 deg. (still without vacuum advance) !!! Re set timing and I am now running a full 34 deg. of timing. this is where my car seems to run the best. 

I love the smell of burning rubber in the morning!

Hey guys. I originally started this topic and have been reading all these variations of set ups. I am currently back to running the car with the stock coil and resistor and the igniter 1. The car runs well but there is a difference in acceleration when pulling away from a light. The acceleration is not quite as sharp as with the flamethrower. The strong smell of exhaust is what I hate the most. I smell the fumes in my clothes when I come into the house. I have leaned out the Holley 4160 as much as possible. I will probably go back to a flamethrower. My question is what version of flamethrower/igniter. Is it worth moving up to flamethrower/ igniter 2 or 3. What is the advantage adaptive dwell? More importantly do I hook up the external resistor? If I hook it up to the external resistor does it affect the voltage going to the plugs. I am assuming that I burn these coils out because I have bypassed the external resistor. Yet instructions and tech support tell me to bypass the resistor.
A bit about the car.The car is bone stock, with fordomatic trans, the distributor was rebuilt about 3 years ago. The vacuum is pulling about 19.5 inches. I do not want spend anymore than I need to if there is not an advantage going to the igniter 2 or 3. I really want avoid burning out another coil.
On another note I have the original carb the car came with. It was a Holley 4150 (390 cfm). After having it professionally rebuilt and taking back 3 times, the car ran very rich. The car would continue run even when I turned in the right side mixture screw. I got fed up and put on a new 4160 (465 cfm). Could the additional 75 cfm cause the rich exhaust smell.
Thanks guys.