77 280z LS1 - starter solenoid / Key switch wiring

[mgood77]

77 280z - 5.7 LS1 

 

Hey, the LS1 starter I’m trying to wire up has a 10g wire coming off the solenoid, from what I could gather from zcar wiring diagrams and the rats nest of original Datsun wiring I have, there is a small 14-16g black/yellow wire coming off the zcar starter solenoid that goes to the key switch. 
 

should I simply hook the black/yellow  wire to my GM starter solenoid? The wire size difference had me a bit concerned that I’m missing something. 

appreciate any help you can offer.

thanks 

Mike 

Edited April 11, 2021 by mgood77

[Phantom]

S30's run the full voltage/amperage through the column switch assembly.  It would be better if you installed a relay so that the full current runs through the relay and just actuation current through the ignition switch like more modern systems do.  It will extend the life of your switch and keep the wiring sizes more compatible.  Bottom line is that the S30 ignition switch really isn't sized to handle the current required for a V8 indefinitely.

Overall remember that you have a vehicle with 40+ year old wiring that is getting brittle and you'll be finding oxidation on all your connectors.  Anything you can do to reduce electrical loads (LED lights, etc) will be to your benefit.

[NewZed]

3 hours ago, Phantom said:

  Bottom line is that the S30 ignition switch really isn't sized to handle the current required for a V8 indefinitely.

 

Relays aren't a bad idea, in general.  But the V8 versus L6 issue only matters to the battery cables.  The small wire only powers the solenoid, which actually has its own relay at the end of the stroke.

 

Minor point.  Maybe Chevy used a bigger solenoid and draws more current.  Or maybe Chevy has a bigger safety margin.  But it's the solenoid draw that would matter.

[mgood77]

Thanks @Phantom appreciate the info. Just to confirm you’d recommend a standalone relay, specifically for the black/yellow wire, not connected to the Zcar starter relay? 

[mgood77]

Thanks @NewZed for the info, much appreciated 

[DonH]

Before you wire that switch direct to your Column and starter signal be SURE and 100% that your 12v+ while cranking also works for your ECU / Fuel injectors / Fuel pump signal. Many times this contact is shorted on the old ignition / key module. MSA sells a replacement for it as well.