1938 V16 stalling / hard starting when hot

[Jeff Trahan]

I recently finished restoring a 1938 Cadillac 9033. During a few test drives, the car stalls and won't restart when the engine is warm (hot?). I had the engine on a test stand and ran it quite a bit before putting it back in the car and hadn't noticed this issue. It may be running a little warmer than normal but the gauge barely gets to the red area occasionally and the radiator never boils over.

I read the post from a few years ago about hard starting in the second generation V16s but I don't think I'm having the same issue with the coils. I checked both coils and although the resistance starts off about 2.5 ohms, it drifts down if I hold it for several seconds into the 1.4-1.5 ohm range.

Today I tried again and noticed after the engine stalled when hot and idling that there was bubbling in both fuel pump bowls and they were only about half full. Then I loosened the fuel supply at the carburetor crossover line and gas started spurting out like it was under pressure. So my guess now is I have fuel vaporizing in the carburetors and maybe in the fuel pumps too. Do you agree with my vapor lock diagnosis? Any suggestions on how to prevent it from happening?

I appreciate the help. I'm planning to use the car in my son's wedding in two weeks but wouldn't want to have to tow it from the church to the reception!

Jeff Trahan
CLC Member #: 28564

[Jeff Trahan]

The next morning, the fuel pump bowls were full and the car started right up.

[harvey b]

Have you checked the timing,I have pretty much the same car and it did act the same way,the timing is critical on these engines,has to be set perfect.It is hard to find someone who can work on these cars,do you have the shop manual or one of the tune up cards for it?.Good luck  harveyb