What did I do wrong here (HEI Conversion)

[zombezoo]

Found this post:
Post
maximum amperage thru this system is right at 4.0 amps--which happens when key is on and there is no rotation of the distributor----then is drops to about 3 amps at idle and declines to about 1 amp at 5000 rpm (when firing 8 cylinders).

Similar search on HEI module draw indicates a similar story, ~6 amps (powered on, not running) falling as rpms rise. Extra power is dumped off as heat when module is powered which is why you need the heatsink.

Not sure if anyone here knows if the draw difference between the factory electronic ignition module and the hei module are enough to warrant wiring changes or not. Was hoping to avoid cutting up my new harness when I install it.

 

[493 Mike]

Do the HEI modules draw much more power than the factory ignition module?

I haven't researched that aspect. I just know the bulkhead connections Chrysler used were barely up to snuff when they were new. Not so much 50-60 years after manufacture!
Mike

 

[ckessel]

Mike, did you use the Bosch relay instead of the OE one for the starter?

 

[493 Mike]

Mike, did you use the Bosch relay instead of the OE one for the starter?

Are you referring to the relay in my sketch? That is just to get clean power to the HEI module.
Mike

 

[ckessel]

Yes sir. Did you replace the stocker with that unit? Just curious as in the future I'll be removing the MSD Distributor/box/coil and going with a oe distributor from E-Booger and use the HEI unit with an E-Core coil.

 

[Canadian1968]

Yes sir. Did you replace the stocker with that unit? Just curious as in the future I'll be removing the MSD Distributor/box/coil and going with a oe distributor from E-Booger and use the HEI unit with an E-Core coil.

I'm pretty sure what he did was tap off B+ of the starter relay, then he has added another seperate relay to power the hei . He used the original blue ign wire to trigger the relay for key on power.

So the high current doesn't go threw factory blue wire anymore it's drawn from the starter relay stud. He is cutting out the potential current loss at the bult head and ignition switch

 

[ckessel]

I'll keep that in mind when I change out the system on the wagon.

 

[Geoff 2]

The coil &.....the bal res....when used with inductive ign [ which is HEI & Chrys & many others ].
Think of the module, ECU as an electronic switch.
If the coil you are using is designed to be used with a bal res, then it must be used.

 

[Geoff 2]

I doubt the the current is dropping off with rpm rise. I suspect the measuring equipment is not fast enough to record it in the shorter time span.

 

[493 Mike]

Yes sir. Did you replace the stocker with that unit? Just curious as in the future I'll be removing the MSD Distributor/box/coil and going with a oe distributor from E-Booger and use the HEI unit with an E-Core coil.

If you refer to my sketch, note the feed for the power comes from the OEM starter relay.
Mike

 

[Don Frelier]

If you refer to my sketch, note the feed for the power comes from the OEM starter relay.
Mike

If I'm reading your sketch correctly (which is pretty good by the way) you have no overcurrent protection in your ignition setup.
You might want to consider something like a 15 amp fuse in there off the "30" wire.

 

[RJ Squirrel]

If you refer to my sketch, note the feed for the power comes from the OEM starter relay.
Mike

Hi Mike thanks for sharing your drawing. What gauge wire did you use for 30 and 85? I think I will add this relay mod when I move my module to the firewall. Might not be getting enough amperage from my blue/brown wires through the bulkhead.
I agree that a fuse or breaker would be a good idea.

 

[493 Mike]

Hi Mike thanks for sharing your drawing. What gauge wire did you use for 30 and 85? I think I will add this relay mod when I move my module to the firewall. Might not be getting enough amperage from my blue/brown wires through the bulkhead.
I agree that a fuse or breaker would be a good idea.

16 should be fine for all of it. Just short runs.
Mike

 

[zombezoo]

Amazon also carries the ac Delco version. Just picked a couple up.
https://www.amazon.com/dp/B0013FZX5S?psc=1&smid=ATVPDKIKX0DER&ref_=chk_typ_inl_img

Received this today, it came with thermal paste.

 

[Fran Blacker]

The paste goes between module and heatsink to transfer the heat better.

 

[zombezoo]

The paste goes between module and heatsink to transfer the heat better.

I know. It's just nice that it comes with paste. The others I have purchased did not come with it.

 

[zombezoo]

Look forward too see your modifications. I don't have any real world Temps from my car yet either ... but it would be interesting to see Temps before and after you add your additional heat sink!

I ended up cutting the bottom fins and two of the main fins to get it to fit. I have nothing to indicate that this is necessary, I just had already ordered the heat sink before I bought your 3d printed mount and figured the extra heat sink wouldn't hurt.