77 280z Restoration

[280Zrewind]

I looked up coil resistance for GM HEI on line and found the range should be .6 to 1.5 and you probably know this, but according to this post, you shouldn’t use a ballast resistor (or equivalent wire is more common now).  The wiring diagram for the 78 doesn’t show one, so unless someone’s done something funky in the past, you won’t have one.  

I don’t know what output circuit the HEI uses, but I could be current controlled so any coil impedance in the range doesn’t make a difference. 

[280Zrewind]

Just saw in a previous post that you removed the ballast resistor. 

[Zed Head]

I matched the module with the coil it came with.  A solid coil (not oil-filled), 0.6 ohms primary resistance, and a factory spec. module.  The Pertronix module supposedly passes more current so the coil will build its field faster and you'll get better high RPM performance.  But, when you're selling aftermarket you have to differentiate.  Can't just sell the factory part for more money.

So, with the high amp module they want you to run a corresponding Flamethrower coil.  But they don't tell you which one corresponds. 

https://pertronixbrands.com/pages/pertronix-ignition-hei-modules

"These modules provide enhanced high RPM performance and when used with their corresponding Flame-Thrower coil, substantially increase spark plug voltage"

https://cdn.shopify.com/s/files/1/0247/6913/4628/files/D2000.pdf

GM 4-PIN MODULE

• Intended for street/strip applications
• 6.9 Amp module

Edited September 4, 2022 by Zed Head

[Av8ferg]

Okay here’s my plan.  This should be fun.   I’m going to mount both the HEI and the Nissan matchbox ignition modules near the coil.  I’ll use the heat sink I bought for the HEI and then build a small aluminum mount/bracket to put the Nissan module on, somewhere below the coil. I’m going to run waterproof modern auto connectors to both units where is can quickly swap the ends that go to the modules from both the coil and the distributor easily.   This will allow a few things.  One to test the difference in both of the modules.  If both function well I can keep running my Nissan matchbox ignition and if I have a problem I can swap to the HEI by just swapping one end of each connector.   I’ve also got a design in mind to mount one half of the connector to where the pickup wires exit the distributor on a plate screwed to the body do the distributor that is neat and sealed up.   This way I don’t have to mess around under there to swap ignition modules as the other end will connect to either module 18” downstream with the female side of the of the wire connector I build.   
I think getting the Nissan Module away from the heat if faces near the distributor will make it far more reliable and give me easy swap out capabilities.  I’m going to mount the HEI like this other forum member did with the same heat sink,  see pic. 
Here are the connectors I bought. 
 

Edited September 4, 2022 by Av8ferg

[SteveJ]

Here is what I suggest to help your project. For the terminations, either for the HEI or matchbox, buy a kit like this: https://www.amazon.com/HUAREW-Connecto-Terminal-Insulating-Electrical/dp/B098DX41Y8/ and a crimper like this: https://www.amazon.com/ProsKit-300-035-Multi-Purpose-Crimping-Tool/dp/B002PI8D4K

I like open barrel terminals more than single crimp since they clamp onto the insulation and the wire. With the proper crimping tool, the open barrel terminals rarely come off. The kit includes insulators so you can reduce the chances of shorting something out.

[Zed Head]

Make sure that you have a good path to ground through the mounting hole grommets.  That is the main ground for the coil charging circuit.  The 4 pin module is actually 5, essentially.

That is probably true for the E12-80 module also.  The manufacturer instructions/labels don't cover that because they expect these parts to be bolted on to the distributors.

Edited September 4, 2022 by Zed Head

[Av8ferg]

Steve, I agree.  I bought that kit and Crimper you recommended.  ZedHead, great input there. Your think the mount bolted to the body would be enough, or you think I should run a dedicated ground wire too?  

[SteveJ]

Use a conductive adhesive between the HEI and heat sink. https://www.amazon.com/Conductive-Adhesives/b?ie=UTF8&node=401542011

[Zed Head]

I think that it depends on how good the mounting surface is grounded.  It might be why the distributor has a ground wire attached (that sometimes gets left off).  Who knows, it might be why your E12-80 failed.  Can't hurt.  A meter reading will tell a lot.

Even if you use conductive paste the heat sink will need to be grounded.  So it's kind of a question of which bolt is doing what.

[SteveJ]

4 hours ago, Zed Head said:

I think that it depends on how good the mounting surface is grounded.  It might be why the distributor has a ground wire attached (that sometimes gets left off).  Who knows, it might be why your E12-80 failed.  Can't hurt.  A meter reading will tell a lot.

Even if you use conductive paste the heat sink will need to be grounded.  So it's kind of a question of which bolt is doing what.

The heat sink should be bolted to the fender. That should be an adequate grounding.

[Av8ferg]

SteveJ, that Pertronix HEI ships with a silicone tube, I guess this the material they want to put between HEI and mounting surface.  Not sure if this is intended to act as a heat dissipation material like you mention and how does this impact the grounding effect.  Silicone is a very poor conductor so this might impact the grounding.  
Here a link to the HEI I bought.  You can see the silicone in one of the pics.  

https://www.amazon.com/gp/product/B000CCFK5Q/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1

[SteveJ]

John, is it plastic or metal on the back side of the HEI? If it's metal, I would say go for broke and use conductive paste. I'm thinking the two holes in the unit for mounting may be the path to ground they want you to use. If it's plastic, use the silicone adhesive and bolt the unit securely to the heat sink. Then the heat sink should be bolted securely to the body. Check resistance between the mounting bolt of the HEI and the negative of the battery to make sure you have a good path to ground.