"Won't restart when hot"; weird solution

[cuzncletus]

My 8ba in my 39 refused to restart after it had warmed up and been on the road for a while. I posted and got lots of suggestions. I had already rerouted the gas lines away from any heat source so vapor lock wasn't the problem. There were suggestions from timing to a low battery.

Here's what it turned out to be. I started from the coil going back to the distributor. The coil was fine, but there was no continuity in the main wire from the coil to the center post of the distributor. I replaced that and the motor fired and continues to re-fire even when hot. Evidently heat was breaking down the carbon wire. Electrons flowed when cold but a gap opened when hot. This might be a one-off occurrence but could be something for others to watch for.

No more carbon wires for me.

[40cpe]

Originally Posted by cuzncletus

No more carbon wires for me.

That's fine if you don't have an electronic ignition.

Thanks for letting us know the cause and solution.

[39portlander]

Good troubleshooting and find there Cuz, I had the carbon Belden edge premium 7mm wires on my flathead, changed them out with the Belden High temperature 7mm that have a stranded cable rather than carbon.

I'm sure Bubba has some good input on this matter.

[coolcoupe]

I having the same thing happening with my 47 stock engine. It starts good when cold but after a drive I shut the engine off then it would not start. A few guys gave me a push and it started right up and ran fine after that until I got home. I shut it off then tried to start it right away, same thing turn over twice and won't start. Any ideas ?

[Tinker]

Originally Posted by 40cpe

That's fine if you don't have an electronic ignition.

Thanks for letting us know the cause and solution.

That is the difference. Hit miss engines with mags require copper coil wire or solid.

[Tinker]

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Originally Posted by coolcoupe

I having the same thing happening with my 47 stock engine. It starts good when cold but after a drive I shut the engine off then it would not start. A few guys gave me a push and it started right up and ran fine after that until I got home. I shut it off then tried to start it right away, same thing turn over twice and won't start. Any ideas ?

So many answers to this. Start coil and work your way out.

[Capt Kirk]

Originally Posted by Tinker

So many answers to this. Start coil and work your way out.

I think there's some confusion between "won't start when hot" and "won't crank when hot". Pushing a car won't heal problems in the ignition so if his car cranks twice and then won't crank anymore and starts when being pushed...it's a cranking problem. My car cranks hard after warmed up and my research so far is leading me to believe that resistance in the starter is increasing as it becomes heat soaked.

[Tinker]

I agree Captain, but how often does a starter not crank? My bad for assuming he meant hot fire vs hot start. Not that it was the the original poster or have I been following the other...

I'd suggest a 00 welding wire battery/starter setup.

[RalphG]

I've never seen a flathead V8 that won't spin the starter when hot. I have seen some older six volt tractor engines that get really lazy when hot and will only crank one turn at a time. A rebuilt starter helped them sometimes.

[Tinker]

Originally Posted by Capt Kirk

I think there's some confusion between "won't start when hot" and "won't crank when hot". Pushing a car won't heal problems in the ignition so if his car cranks twice and then won't crank anymore and starts when being pushed...it's a cranking problem. My car cranks hard after warmed up and my research so far is leading me to believe that resistance in the starter is increasing as it becomes heat soaked.

only time it helps to push a car is when you spend 30 minutes trying to figure out what's wrong and then try and push it after the coil cools.

....or the starter locks up on the flywheel or there are teeth missing on the flywheel.

[coolcoupe]

Sorry I hi-jacked this thread but it seemed like what my car was doing. I will try a different heavier starter cable. Thanks Guys