We tring to figure out to hook up our own igntion switch and everyone here at the shop has there own ideas. Basically we want to have a push start button to turn the motor on...heres a trickier part, we want to run a switch to turn the car off or make the push button (since it is technically a momentary switch) turn the car off again when you press it in. Basically, push one turns the motor over and push two turns the motor off.

Anyone with any clue please help and give some feed back. The motor is carb'ed so we don't want to just turn off the fuel pump because it takes a while ti kill a carb'ed motor. The car is a 96 Z28 with everything stripped from it. We have the fuel pump hooked up to a switch, fans to a seperate switch, electric water pump on another switch. We are ready to hook up some sort of ignition switch.

Thanks!

 

Do you want the start button to just energize the ignition, or the ignition + the starter motor?

If just the ignition, that's easy. There are pushbutton switches that aren't momentary. Push once to close the contacts, push again to open them.

If you want one momentary button to work the ignition and the starter, you need to introduce logic, something like maybe a PLC. Would get complicated. But there is a way to do it with 2 momentary push buttons and a relay w/2 sets of NO contacts.

1st momentary button (with 2 normally open contacts) would kick the starter over for as long as it was pushed using 1st set of contacts, and also energize a relay with the 2nd set of contacts. One set of contacts (NO) on the relay would then be used to send juice to the ignition circuit. The other set of relay contacts (also NO) would be used to feed voltage back to the relay coil to keep the coil energized after you let go of push button #1. The relay would stay latched like this, and keep the ignition juiced, till the voltage feedback loop was broken.

You would break the loop with the 2nd pushbutton switch, a normally closed momentary. When you push it, contacts open, relay unlatches, voltage to ignition is killed.

This is also a form of logic (relay logic) and was the forerunner to the use of PLCs in industrial automation. Entire assembly lines were run by banks of relays and swtiches. Hope this makes sense cause I just came home from working graveyard shift and my brain is entering shutdown mode, time to hit the sack.

 

Why not a switch kind of like an ignition switch with 3 positions..... Off, On and On + Start. I'm sure somebody makes a dash-mountable rocker switch like that somewhere.

But I don't actually like that setup on a competition vehicle- I like to be able to turn the ignition on and off completely separate from cranking the starter. On a hot engine it's often easier to restart by cranking the starter and THEN turning on the ignition to help overcome dreaded hot start "kickback" and slow cranking.

 

Ever here the term KISS. Put your ign. and starter on separate switches. Many places make switch panels ready to go, Painless Wiring is one.

 

Thanks for all you help guys.

Angel71rs: Thats what our boss came up with and he said that would be the smartest way to go.

Z28SORR: Thats what we are going to do except make our own switch panel.

I decided that it would a good idea to have a switch for the starter and a kill switch for the ignition. There aren't very many electronics on the car right now but I'm sure as the car progresses we'll introduce more into the system. We're going to hook it up like my dune buggy, "momentary" switch hooked up to the starter, then a kill (toggle) switch inbetween the alternator and coil. We have everything on it's own little circuit in case of fires or other emergecies. The fuel pump was a big "iffy" because the boss man wanted to run it on the ignition so as soon as the ignition was turn on, the fuel pump would turn on automatically instead of have to flip it on while turning the motor over.

Do you guys see any down side in having to manually flip the switch on (for fuel pump) and should we just run it with the ignition where it'll always stay on until the igniton switch is flipped off?

 

Like I said my dune buggy is hooked up just the way you described and it has run perfect for the past 5 years. I too like having the ignition on a seperate switch, especially for competition cars. We have this LT1 built pretty nice and figured we break the car in by running it at the track till we begin to notice "changes" in the body. Unibody's are awesome vehicles but I seriously doubt it'll with stand what we want to do with it. Eventually we are wanting to run a 526 alky blown chevy motor but the front end of the camaro isn't big enough. The 44 mags are mounted on the front of the motor and we'd have to relocate it or switch over to a MSD-10 (plus) but it's a little too much work right now.

I think we are going to like the results we see when the car is all said and done with the small block.