[crussell85]

This will be my third year running in a demolition derby. One of my problems out on the track is that everything is so noisy and then with a helmet on and being pushed around by other vehicles I sometimes don't realize that I am not running. I am still shifting to move forward and reverse but being pushed around by other vehicles I think I am powering my vehicle. I know this sounds kind of funny but its true. So if I think I am running and I look over and realize I am being counted I then realize I must not be running. My question is if there is any way to hook up a light to either go off or come on to tell me that I am not running. The light would either have to power up or down when the engine only stalls. So if the power toggle switch is on the light would stay off or on until the engine is started the would turn off or on when the engine stalls. Is there any way to do this?

[ericnova72]

Just use a tachometer, you will know exactly when and how fast the engine is running that way.

You could also just use the alternator (charging) light in the dash.

[crussell85]

good call never really thought of that

[75gmck25]

You could also just use a larger, more visible charging light maybe mounted on the top of the dash.

The alternator line to the bulb has 12 volts on the ignition side if the car is on, and when the alternator is running there is 12 volts on the other side of the light. This means the bulb does not light up because there are 12 volts on both terminals. As soon as the car quits running you have ground/0 volts on the alternator side, and 12 volts on the ignition side, so the bulb lights up. You could easily add another charge light and mount it on top of the dash where it is very easy to see.

Bruce

[crussell85]

can someone give me a link to a wiring diagram to wire the car or tell me how the car should be wired to be wired as a demolition derby car. Basically wired enough for the car to start,run,and charge.

[75gmck25]

If its something like a carbureted SBC, you don't need that much to keep it running.

- battery positive running to the large lug on the starter (used as a junction)
- Battery ground to alternator bracket; pigtail ground from battery to body and ground from engine to body

- alternator charge wire from the large lug on starter up to the BAT terminal on the alternator; fusible link on the starter end of the wire
- alternator charge wire is usually jumped over to the #2 terminal (sense wire) on the alternator; it needs 12 volts from somewhere
- main power wire from the large lug on starter up to the junction on the firewall; fusible link on starter end

- from junction on firewall - power wire to the ignition switch and fuse-box
- from junction on firewall to unswitched 12 volts; maybe not needed on a derby car since you don't have any lights

- Switched 12 volts from ignition to HEI BAT terminal
- switched 12 volts to whatever else has to run when the car is on (electric fan?)
- switched 12 volts to the alternator #1 terminal, with either a bulb or resistor in the circuit

I think that's all you need.

Bruce

[sqzbox]

Raise your idle speed over 1,000 rpm. with manifold vacuum to the dist.

[crussell85]

ok thanks everyone, any suggestions that I should do to the car to make it run and start better is appreciated. The car is a 1973 Pontiac Catalina that will be powered by a SBC 350 and trans