Hey Bill

Are you running a pointless ignition on that or not? Sometimes the condenser in your dizzy can overheat and stall the engine and then once it cools down can start again.

Sounds like an interesting one.

A faulty ignition coil can cause the same 'cutout' problem, then it seems to correct itself by cooling down. This won't cause the starter motor to labor but the engine won't start.

If you have another ignition coil, swap it before buying another.

Engines don't start running well until they are 'up to heat'. Modern engines are designed to run hot (195-degree F) thermostats, with 19-psi cooling system caps. This allows fuel to burn more efficiently for better economy. Engines love it.

Another caution is, ignition timing. If too far advanced, hot pistons will make your engine hard to start. A properly set distributor should retard timing at startup, when there is no vacuum. After 'starting speed' turns into running speed, that's when the vacuum pancake advances ignition timing by pivoting the points plate. Some Pertronix units have this as a built-in feature. With more engine speed, the distributor weights continue to advance ignition timing to its max. - Dave

Yes agreed.

After having a chat with Bill he said that he wasn't even getting a "click" coming from the starter solenoid, but he did however have ignition lights on the dash.

This would lead me to believe that it could be a bad earth or electrical connection somewhere like a high resistance in the ignition switch or a plug/connection.

Enough voltage flowing through to the system to cause the dash lights to come on, but not enough to allow the starter solenoid to engage, or anything with high current draw.

As you would be well aware, copper is a PTC material so if the engine bay is getting hot and making the wires hot, its resistance will increase and could possible cause voltage drop issues. (on top of the volt drop that would already be present from old wiring)

Thank you guys, I'm not running the Pertronix on this one....yet... and I have swapped coils as that was my first "unqualified" thought. As Michael (Wyldie) knows, auto electrics is all voodoo to me even though the principles seems basic enough. Guess I'm just scared of it.

The other thought I had was the ballast resisitor, I have no idea what this does but could it be an issue?

I regard the ballast resistor as part of the ignition circuit, not part of the starting circuit. In other words, the starter solenoid shunts around the ballast resistor when it energizes.

This is new information... I didn't read that the starter solenoid does not energize. The description sounds to me like the engine cranks very slowly "...similar to a dead battery but everything else electrical worked."

There is no electrical protection in your starting or your ignition systems. There is no fuse, either. It's a straight shot from the battery, to the headlight switch, to the key switch, to the neutral switch, to the starter solenoid. There are bullet connectors in the path.

Certainly, a loose connection will cause intermittent problems. Usually, a large current will separate the connection at the fault. Check that your starter solenoid is bolted tightly to chassis ground.

Bill, you struck a nerve in saying the dash devices work. There is a very short yellow jumper from the headlight switch (B) to the key switch (B) terminals (look on your wiring diagram). We have seen this wire come loose. It has ring terminals on both ends, and nutted down on screw-posts. This is one of those power wires that must be tight.

Don't worry, I won't hurt you. I would remove all jewelry and disconnect the starter wire at the solenoid. Then, turn and hold the key in the 'start' position while feeling around the back of the key switch and the headlight switch. If there is a loose connection you will hear the starter solenoid turn on/off like a jack hammer.

If everything seems solid, connect a 'test lamp' from ground to the starter solenoid's 'S' terminal. If the light shines bright without interruption during your test, you probably have a bad solenoid. - Dave

True, a positive temperature coefficient (PTC) refers to materials that experience an increase in electrical resistance when their temperature is raised. Heaters (like the cigarette lighter) use a high resistance nickel/chrome coil of wire, as an example. As the metal gets hot, resistance self-limits current. That's why they work fine with a ten amp fuse.

But electrical conductors have such low resistance that even with heat elevation, there isn't enough difference in resistance to make a big difference in voltage (voltage drop). Electric wire tends to arc and eventually burn itself 'clear' under a loose connection.

The big thing with copper is how much it expands and contracts with heat and cold. We caught a guy stealing thick copper wire at work one day, just by happenstance. He wrapped heavy copper wire tightly around his chest area in several layers so it wouldn't slip down, then he set out to his car on a bitter cold Michigan winter's day. This guy didn't get half way to the employee parking lot before he fell out. Nobody knew why until they got him inside and took his coat off. He turned that wire into a boa constrictor that nearly froze and suffocated him. We couldn't stop laughing. - Dave

Thanks Dave, I will give this a try and let you know the outcome.

I ran the battery ground to one of the starter mount bolts
check the voltage starter ground to battery positive..should be the same as the battery.i.e. 12.5 volts across the post...
lakebird

Cheers for the suggestions guys, one weekend when Wyldie and I get some time, we are going to try and replicate the problem so that we know exactly what we are dealing with. Much easier to diagnose when its happening. As we are going into autumn and then winter we may have to wait a little while to get the engine really hot again, but that's all good, it isn't going anywhere!

I will update once we know.