Steve,
Correct, the + coil wire is connected to the ignition switch. We can change that.
Want to let you know that I've added a ground to the block and left the fire wall ground in place ( u  can never have too many grounds)
Will send you an update.
Big thanks,
Tiny Tim
Fl 33706

The illustration I found shows a key switch to the coil power - don't. On the systems I've built, I used a power relay for the heavy lead to the coil - and left that wiring outside the passenger compartment. The key switch fires the relay. A jumper from the starter solenoid will give it power while cranking.
The highest electrical potential on the vehicle (volts) exists between the frame of the generator/alternator and its output lead. Since it is usually bolted to the block - the engine block is the next best ground available. 

Ford had service problems with the old Duraspark II ignitions of the seventies - the distributor ground was wired back to the controller box on the fender liner. Adding a wire from the block to the distributor body made many gremlins go away. There were other troubles - but this one was easy..... 

 
 Steve Metzger       Tucson, Arizona

Right now  the ground is to the fire wall, I'll move it to the block and see what happens.
The funny part of this equation is that for last 3 years and 8 months the ground has been to the fire wall with no problems. Last summer drove to Detroit and back with no problems. All the problems started this summer.....WHY??????
Thanks again,
Tim
Wet, Florida
33706

I haven't looked at one of the units you have - but if the trigger and "controller" (transistor package) are built into a single unit - and then captured inside the distributor body.......... the unit has to have a secure body ground wire (to the block) - and the controller has to be transferring heat out of the electronics as well as grounding it to the body. On a GM HEI unit - carried inside the distributor - the unit has to be clamped down with "couplant" (heat transfer paste) - a dry surface beneath one is trouble. Most of these gadgets have a protective "interrupter" circuit to prevent overtemp from destroying the electronics. When it cools down - they turn back on. Sounds like what is happening to yours.

I haven't looked up the Accell #8140 - but you are interested in the OHMs of internal resistance they report. The 42K volts is the dielectric resistance of the wire in the coil - not the output of the unit.
Later: looked up the #8140 coil - primary OHMs are shown as 1.4
only diagram I could find for this set-up



 
 Steve Metzger       Tucson, Arizona

Thanks for your informative information.
The new coil is a ACCELL #8140 that is advertised to have 42,000 volts.
Also, and this is a test, I used two strands of # 10 copper wire wrapped together as a coil wire.
This works, but have not driven the car any distance (15 miles or more)
All I know is that after the car cools down for 30 to 45 minutes, it fires right up.
Thanks again,
Tim
Hot 'n Humid
Florida 33706

Are you trying to keep the cylindrical coil - or is a modern "E-type" with high temp wire allowable? The key issue is how many OHMs the coil or combined coil and ballast resistor are placing in the circuit. The Motorola "chip" (or a copy) that the common HEI type ignitions are using runs as many amps as it takes to "saturate" the coil. It varies the "dwell" to do this. They often need a pretty big power wire when using a low OHM coil.

The "high voltage" that coil manufacturers advertise like crazy - "50,000 volts" is a common ad - only refers to the insulation properties of the winding wire. In practice the coils are firing at about 10,000 to 12,000 volts so plenty of safety factor.

One of the "CD" type ignitions is a different animal  - they deliver high voltage / low amps.

 
 Steve Metzger       Tucson, Arizona

I tried contacting them on Monday by phone and then an email. They could be on vacation or out of business.
Their web site is still up and running. CRTPERFOMANCE.COM 
I agree with you that the coil has to be comparable with the HEI distributor. When I bought the HEI, I had a Pertronic unit with a
40,000 watt coil . Roger at CRT Performance said it would work fine with the distributor. I'm not sure what the watts are on
this new MasterPro coil that we bought at O'Reilly's. Will be checking that out. And I'm going to check out an coil with an
internal resistor.
Thanks for you support and help.
Tim
Florida 
33706

Consult the instructions and / or contact the manufacturer of the electronic distributor to ensure that the coil matches and for guidance about the ballast resistor.


Lawrenceville, GA

There is no such thing as "FREE"

Mfg of new coil "MASTERPRO IGNITIONS", nice people:

Recommended a ballast resistor or a coil with an internal resistor.

"FREE SAMPLE"