I have tried to start my 72 240z but when I continue to turn the key the resistor keeps getting really hot. What kinds of things could cause this?

Which resistor?

BTW, all resistors get hot when current is flowing through them.

The external resistor that is near the coil. I know that resistors warm up, but it gets really hot, like too hot. The coil also warms up too. I'm wondering if there is a short in the system.

How old is your coil? It could short internally.

Well that's what I thought at first but have tried three other coils, while none of them are new, I doubt that all of them are bad. So ya... I kinda ran out of ideas.

Do you have the factory wiring/points setup or an upgraded ignition?

Does the car start at all? When does the coil/resistor heat up, only in the staring position, or also when you just switch on the ignition without starting?

The coil/resistor heats up considerably when the points setup is broken (points are always connected, points wire has ground contact). If the wiring is wrong (ground connected to coil (-)), then you would have the same effect.

Alhbln has a good point. Have you checked your dwell? Also, how old is your resistor? Could it be the culprit?

Well first of all that is an awesome pic Alhbln. All the wiring is original as far as I know, but I just put in a brand new ignition. I have checked the wiring diagram I have in my owners manual thing and as far as I can tell all the wires are hooked up correctly. I have not been able to start the car because I have been trying to work out all the kinks and I just found out that the compression is off so I have put another of my engines in. But when I was trying to start it I would turn it over and check the resistor and it would be burning up and the coil would be warm too and unless I unhooked it it would stay hot.

Oh an SteveJ I actually bought a new resistor because I thought that might have been the problem.

All the wiring is original as far as I know' date=' but I just put in a brand new ignition.[/quote']

Do you have installed a factory points ignition setup or an aftermarket item, such as the Pertronix Ignitor?

... But when I was trying to start it I would turn it over and check the resistor and it would be burning up and the coil would be warm too and unless I unhooked it it would stay hot.

Assuming that you have a points setup' date=' it sounds ike your coil's (-) terminal is permanently connected to ground. You should have two wires going to the coil, a black/white wire to coil (+), and a black wire to coil (-).

Check out where the black wire from coil (-) is connected to, with a factory points setup it should be going to the distributor's spade terminal (the spade terminal is mounted on a white plastic block on the distributor body, above the condenser):

[list']

[*]If the black wire is not wired to the spade terminal, you need to fix the wiring as shown below in the circuit diagram

[*]If the black wire is connected to the distributor body, you need to make sure that the points setup is ok and that the black wire with the yellow ring inside the distributor (connecting the spade terminal to the breaker contact) does not touch ground. You might also check the capacitor, if its broken there is a small chance it short wired the spade terminal permanently to ground.

Ok, thanks. I really appreciate it.