Relay to Ignition Coil Wiring Schematic

[earlymopar]

I'm searching for the correct wiring schematic for a relay to ignition coil set-up to provide direct battery voltage to an HEI and be able to have the ignition switch turn off the engine. What I have is a 12 Volt 4 Pin SPDT Automotive Relay 30A/40A like that seen below. I understand the leads that need to be attached but not correct connection points by terminal name.

Thanks,

- EM

 

[scott657]

SPST
85 Ground
86 from IGN SW
30 from Bat
87 to HEI
other wiring dependent on ign requirements
why wouldnt you go from IGN to HEI

 

[earlymopar]

SPST
85 Ground
86 from IGN SW
30 from Bat
87 to HEI
other wiring dependent on ign requirements
why wouldnt you go from IGN to HEI

Thanks Scott. I get small power loss as I go through my existing wiring, bulkhead connectors, etc. This will eliminate those. -EM

 

[earlymopar]

Shouldn't #87 go to the coil +?

 

[67Dart273]

One problem with NOT using a relay is that harness/ switch/ bulkhead connector voltage drop causes battery overcharging.

Electrically (you can upgrade the wires, I'm referring to electrically / functional / as stock)

You cut the blue "ignition run" IGN1 coming out of the bulkhead and feed the end coming from the bulkhead connector to the relay coil 86

The ground for the relay coil, you can also run to ground through a hidden switch and create an anti theft "simply." 85

30 come off the start relay "big stud" through a nice big fuse and heavy duty fuse holder, 20-30A or a breaker, that is your main power feed

Then electrically, the other cut "ign1" going to the underhood harness goes to the switched contact 87

NOTE THAT if you still have the ammeter, this change will move it "wrong" by whatever amount the alternator field/ regulator and the HEI draws

 

[GTS Dave]

I found this elsewhere on the internet.
Compare for reference and use 67Dart's suggestions.

 

[67Dart273]

I see I made a mistake and so did they. You want to jumper the brown to the blue if you are not using a ballast and feed that to the coil of the relay. They are showing just the brown which is misleading.

 

[earlymopar]

Thanks much fellas. This is very helpful. Yes, I had previously spliced my Ignition #1 & #2 leads together.

- EM