Problems starting when hot

[G.M.]

thanks for clarification!

To me popping the clutch means to push or let the
car roll down a hill with clutch pushed in and when
it is rolling take your foot off fast and the engine
turns over and hopefully starts. When I was 16 this
was the normal method of starting every day, never
had a good battery. G.M.

 

[Mart]

Pop the clutch. = lift your foot off the clutch pedal quickly. Also known as dump the clutch.
To start while pushing - push start or sometimes bump start.

If it started when push starting, but not when using the starter to tun the motor it might indicate a heavy current draw on the starter. Poor earth (ground) maybe?

Plenty of volts in the battery to start it when pushing, not enough volts left for the ignition when starting on the starter.

You said slow to turn at first. Could also indicate poor earth. Don't forget where the starter bolts to the oil pan needs to be clean metal, not painted.

Lots of heat in the starter won't help. Lots of heat under the hood when in heavy city traffic.

If running in heavy traffic don't switch off if you can avoid it.

Mart.

 

[JSeery]

Also, when the ballast resistor is hot, it is reducing the voltage to the coil more than when it is cold. So you have the voltage pulled down by the starter draw and the ballast resistor at maximum resistance. That's what's nice about the later ballast by-pass when the key was in start, but no help here!

 

[JM 35 Sedan]

It's been my experience with working on these early Ford's for some years now, that many of the original coils have some degree of wire insulation degradation, which allows coil windings to begin shorting under heated conditions. This causes weak, intermittent spark at plugs, or sometimes a complete failure. My suggestion would be to have an original coil rebuilt by rewinding with modern magnet wire that uses a higher temperature, higher grade insulation. Not sure if you know where this could be done in your country, but in the US we have Skip Haney, in Punta Gorda, Florida who does a very good job of this at what I'd consider a reasonable price.