”˜48 Fleetline with a ”˜52 235 rebuilt 2000 miles ago. Starts great when cold, I have an electric primer pump, but after she’s up to operating temp it just won’t fire. Seems to turn over a bit slower?
Valves are right, just installed a new vacuum advance and set the timing with a light. Car runs fantastic just won’t start after it’s warmed up? Any ideas, I don’t know what else to do?

Three ignition components and battery cable ends are likely suspects.

As temperatures rise so does resistance in electrical connections. Make sure that all connections are clean and tight. A little dielectric grease may not hurt.

Wires inside coil lengthen, internal shorting is possible. Cool by pouring water on coil to see if that helps.

Corrosion on points can dramatically increase resistance when heated. Clean points and maybe reset.

Shorting in condenser more likely when hot. Replace if questionable.

If the restart problem occurs after 5-30 minutes after being shut off, it may be gas percolating into the intake manifold from carburetor. Fully open throttle plate while cranking to clear too rich mixture.

There are a few other possibilities but the above are by far the most likely.

A hot motor will have more compression and puts more demand on Battery.....
So when its hard starting, and turning slower i suspect battery first, or battery. Lets us know what you find.
.

I went back and checked all connections, checked resistance on several wires to and from the coil, both cold and hot and found nothing out of ordinary. I think maybe the starter is a bit weak? I retarded the timing a few degrees and that seemed to help, seemed like the motor spun over faster.
Is it time to have the starter looked at?

Dan, If the car is still 6 volt, check that the battery cables the proper gauge. Even with good connections, smaller gauge replacement cables may be the cause. Mike

Spark is the first thing to check. Pull the wire from the coil to the center of the distributor cap and arc it to ground while cranking. I don't have an idea of the minimum acceptable jump distance, but I'd sure be looking for more than 1/8". Both coils and condensers can get worse when heated. I once ran a '53 Chevy in very cold weather. I had a 6V motorcycle battery in the front seat and could switch the ignition system to it for cranking. It would start with amazingly slow cranking, maybe 60 RPM. Be sure your accelerator pump is working, but don't overuse. With practice, you can sometimes get a start by releasing the starter button just before a spark fires. The rise in battery voltage when you remove the starter load can give you a nice spark on the next point opening.
Triple check point spacing
Wilson

Thanks for the tips Guys. Battery cables are big and new, I forget gauge, accelerator pump is working, points are right at .018 and clean.
Wilson, you mention fire as soon as you let off starter, I remember this happening several times so that makes sense that part of the problem is a weak spark when cranking. Just replaced the condenser, I have another coil I may swap out when the motor is hot.
Thanks again for the help, I really need to get this sorted, last weekend I carried a bride and her father to her wedding, well when we got the signal to go I had to get the dad to help push off the car to get her started!

I had a somewhat similar trouble until I stoped trying to burn ethanol fuel. A case of vapor lock.

My forty was almost impossible to start hot. Changed to non-ethanol gasoline. Problem solved.