12 step solution for ET challenged GT ignitions

[tekenaar]

Simplest installation of electronically triggered ignition in a GT is to purchase and use Pertronix/Hot-Spark trigger and stock coil. Here's how:

1. Remove cap, rotor, points and condenser with green wire from distributor and disconnect green "condenser/points" wire from coil. Leave everything else connected as-is.
2. Install Pertronix/Hot-Spark trigger amp module where points were, do not tighten mounting screws yet.
3. Run red and black module wires out "points wire" hole in side of distributor and install grommet in "points wire" hole, leaving a bit of slack on both wires inside of distributor.
4. Push black plastic magnet unit onto distributor shaft and seat over points cam.
5. Adjust trigger amp module to magnet unit clearance using clear plastic gauge that is provided and tighten trigger module screws.
6. Replace rotor and cap . . . you're now done with the distributor.
7. Connect black Pertronix/Hot-Spark wire to coil contact from which you removed the green points wire.
8. Cut an 18" length of 16/18 gauge red wire, strip both ends ~1/4" and crimp on a 1/4" female spade connector on one end.
9. Locate clear (resistance) wire at front of fuse #3 (from passenger side) of the fuse box and attach red wire terminal on an extra lug there. This is your switched 12V (turns on with ignition key) source for powering Pertronix/Hot-Spark.
10. Run the other end of the red wire through the firewall at the windshield washer foot pump hose grommet.
11. Crimp 1/4" male spade connector to red wire now underhood and connect to matching Pertronix/Hot-Spark red wire female spade terminal.
12. To paraphrase our own SouthWest Airlines: "You're now free to move about the country!"

[Motor Mouth]

An 'idiots guide' fantastic.

How much does the Petronix unit cost?

[tekenaar]

An 'idiots guide' fantastic.

How much does the Pertronix unit cost?

Depends on where and when you buy it . . . Bugstuff usually has it on sale for about $45 during Carlisle and at Thanksgiving. That's generally thought to be about the least $. Have purchased all of mine from them except for the very first one back in '78 when Pertronix was still Perlux and speaks for itself as far as reliability is concerned. Still own that GT which I converted to FI back then . . . one of the very first FI GTs anywhere!

[d slaton]

I need more help with step nine, my first time with this and I'm not sure how to find this resistance wire or lug. Thanks for any help

[tekenaar]

I need more help with step nine, my first time with this and I'm not sure how to find this resistance wire or lug. Thanks for any help

Fuse box inside GT, front of 3rd fuse from passenger side is where clear, resistance wire for coil + is connected. This location has a couple of spare male spade lugs to which you would connect the female spade lug of the red wire you just fabricated per instructions.

[asdasc]

I have a 70 GT (my 3rd one) and the PO added a Pertronics Coil and Elec Ignition. I was told that with the new coil, I still need the resistance wire. Supposedly Pertronics makes two different coils and you can't tell them apart. If it 3 ohms, you need the resistance wire. If it is 1.5 ohms, you need to replace it like the instructions here say. You can easily measure the resistance with a decent ohm meter. Just be sure to disconnect everything from the coil before measuring.

[tekenaar]

I have a 70 GT (my 3rd one) and the PO added a Pertronics Coil and Elec Ignition. I was told that with the new coil, I still need the resistance wire. Supposedly Pertronics makes two different coils and you can't tell them apart. If it 3 ohms, you need the resistance wire. If it is 1.5 ohms, you need to replace it like the instructions here say. You can easily measure the resistance with a decent ohm meter. Just be sure to disconnect everything from the coil before measuring.

If coil is ~3 ohms (has internal resistor), you DON'T need external resistance. If coil is ~1.5 ohms (no internal resistor), you need external resistance and separate wire with full 12V to Pertronics!

[EJprovost]

Just printed this out, Thanks for laying this out so easy to understand.

[asdasc]

Thanks Tekenaar! Now I have to go back and double check what I did. What you say makes sense, and it seems to be running ok. By the way, after reading your other posts, I am going to re-jet my DGAV!

Thanks for keeping me straight!

[asdasc]

Hello, Does anyone know what the 'gap' is in step 5? The module in my GT was installed by the PO and I am not sure if it is right. I am having some minor ignition issues, and am trying to figure out what is causing it. I DO know that I need to run 12v to the red wire on the pertronix. The PO had it run to the resistor wire.

Thanks,

[markandson]

Per the Pertronix instruction sheet the proper gap is .030"

[Willy_g77]

I just ordered the pertronix 1847v unit and flamethrower coil. my question is that, do i have to run a resister wire when using the flamethrower coil? thanks in advance, im sure i'll have more questions when it gets here.

[bullmoose]

Sorry if this sounds like an obviously dumb question, but will the gap between the Pertronixs bits affect the dwell? I set the gap using the included spacer, and am getting a solid dwell of 55, which is more than stock. I haven't experimented yet, and figured the answer might be beneficial to many. I figured it was all set within the device and not adjustable, with the spacing nothing more than the point at which the unit activates, so I haven't bothered checking.

[opelwasp]

Not a dumb question. A Pertronix uses a "Hall-effect" magnetic proximity sensor and magnets to trigger the coil. Points, essentially a switch, "trigger" the coil when opened. Dwell is the measurement of how much time it takes the points to go from touching to it's furthest point. Like I said the Pertronix is magnetic and they never touch. So dwell is not so much a factor. When you get a Pertronix it does come with a .30" spacer to set the proper distance for the magnetic field. You do usually need to adjust the timing though, it will be close but not quite right.

[BDD]

Riddle me this.

I have a Bosch coil that measures just a bit over 1 Ohm resistance from +terminal to -terminal will all of the wires hooked up (before installing the Pertronix.

When installing a new fuse block and connecting the wires I noticed that the clear resistor wire had melted insulation from a short. That was awhile ago so I forget if I or a previous owner connected a wire from the fuse block to the +terminal of the coil to replace it.

What resistance, length, gauge should the resistance wire be if I want to re-use the stock (1+ Ohm) coil with a new Pertronics unit?

What gauge wire should be used to go from fuse block to Pertronics and coil for the new setup if still using a resistance wire and stock coil?

Is it better to take out the resistor wire, replace with new wiring (at the same point on the fuse block) and get a new , points style, 3 Ohm internal resistance coil?

What's your favorite color?

Thanks.

[BDD]

Does anybody have any opinions on the last question I tacked on to this thread? I want to install a Pertronix ignition tomorrow and was going to use these responses to decide which way to go, new coil? Stay with a stock type coil? I found one that has 5 Ohms resistance. Keep a "resistor cable" (as the schematic calls it)?, etc.

Thanks.

[Gordy]

I have a Pirrahna electronic ignition in my 1970 GT that I bought new in 1979 from Auto Sport in Calf.. It has been trouble free for almost 30 years. In all my other Opels I have the Pertronix systems and also have had zero problems. One difference is the Pirrahna has a 3" x 4" by1/2" "box" which mounts and the wires lead into it.

[tekenaar]

Does anybody have any opinions on the last question I tacked on to this thread? I want to install a Pertronix ignition tomorrow and was going to use these responses to decide which way to go, new coil? Stay with a stock type coil? I found one that has 5 Ohms resistance. Keep a "resistor cable" (as the schematic calls it)?, etc.

Thanks.

Read this entire thread about coil/resistor recommendations . . . found it by using SEARCH - "Bosch coil" . . .

[tekenaar]

Look here for info on external resistors to use with non-resistor coil like stock "tan-top" Bosch . . .

. . . and another on Bosch coils used on Opels!