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I have degrees in engineering and applied sciences and got one of my few A's in thermodynamics.

I collaborated with Connecting Rod Serling. What we believe happened is someone's car would not start and it was diagnosed as "vapor lock". Thinking that vapor lock occurs in the pump to carb line the owner rounded up some clothespins and put them on the line. The car started, total time 5 minutes. Actually vapor lock is in the tank to pump line but through some dark magic the clothespins on the wrong line cured it and a new "science" was born.

Then we decided to experiment. Another car had the same problem, we rounded up some pink ribbon, cut 6" lengths, tied them to the fuel line, cured!! Took 5 minutes. Next time we tied them to the antenna, cured!

Man, Rod and I were golden, we were gong to open a repair shop. Then it occured again on a day we were dog tired from all of our experiments so we downed a few Coronas (not the Toyota type). Bam, the car started after we had relaxed for 5 minutes. Better than golden, we could fix cars, get drunk, do nothing and get paid for it.

If you look at my post #15 in 46-54 "Chasing rough idle" , the Factory Service Manual says that a "no start" condition when hot is usually flooding. I posted it , nobody mentioned or commented on it??? (Twilight Zone has the answer)

The cure for flooding??? Let the car sit.

More tales from the twilight zone in future weeks, running some real experiments.

Oh yeah, the new science of the clothespins is called superstition.

Submitted for your consideration, you are now leaving the Twilight Zone.

PS, I just changed the waiting time from 20 minutes to 5 minutes, more reasonable. Positive results did not change however.

I'm going to have to try that Corona trick.

Fred, funny story. However, that's only half the story, isn't it? How about an A-B (or A-B-Corona) experiment where an electric pusher pump is added?

Waiting 20 minutes is not always a luxury available. Try it in Las Vegas stop-n-go traffic in 115F temperature like I have! You'd get that electric pusher pump installed pronto...and then have a Corona at home with your Packard parked safely in the garage.

Craig

That's what I've resorted to, and I no longer worry about the car stalling in rush-hour traffic downtown. At first sign of hesitation, I just flip the switch and "bam", she's running smoothly 'gain.

West Peterson Quote:

There's no reason to not leave the electric pump on all the time. That way, you never get surprised.

Craig

As I said, "real" experiments will be done in the next month or so on other fuel problems discussed in other forums here. This is not half the story, it is just an explanation on the "clothespin" cure.

From the September 1933 Packard Service letter:

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Perhaps the origin of the cure is that the gas tank shields were fastened with clothes pins?

I wonder how close the crossover tail pipe was to the steel fuel line from the tank to the fuel pump in front? The fuel tank is a BIG heat sink compared to the fuel line and would be cooled by air passing under the car while moving.

A bigger issue as pointed out in this Service Letter is the volatility difference (in 1933) between "Winter" and "Summer" blends of gasoline. "Winter" has a relatively low volatility WRT heat and pressure so that the car will start when it is cold. "Summer" has a relatively higher volatility so that it is not as likely to vaporize in the fuel lines leading to the fuel pump because mechanical fuel pumps do not pump vapor, only liquid.

Of course, this is in the days before 10%-ethanol blend, which makes the situation even worse (1.0 psi less Reid Vapor Pressure according to the EPA). Also any car in 1933 would be unlikely to drive between two significantly different gasoline blend areas (high to low altitude or moderate temp to summer time desert) in a short time in the days before the Interstate system.

WRT the vapor lock problem in general, all you really need to know is that modern cars with fuel injection do not have this problem. This is because the fuel line pressure is about 10 times more (45psi vs 4.5psi) with the internal tank mounted electric FI pump compared to virtually any mechanical pump with carb.

Well presented and well understood. Modern FI cars have the pump in the tank so there is no suction in the lines which is what makes the gas vaporize, as I understand it.
With our cars, perhaps the problem is encountered at tiems because we tend to "winter" our cars with a full tank of gas to eliminate condensation etc. Then when summer comes adn we hit the road in a Memorial Day parade at 90 degrees we encounter vapor lock with the winter gas. If we don;t do 200 miles all summer we're ripe to encounter it again.

I understand your points about the temperature of the tank, cooling airflow etc etc, but I donl;t think the brain trust at East Grand Blvd would have published something if it weren't really helpful. Crawling in traffic at 100 degrees there's virtually no cooling and a tailpipe in close proximity is like a teapot on simmer, it only heats up the tank. It only has to hit a certain point when the additional engine compartment heat causes vapor lock just before the pump.

As time allows I will be doing some experiments in the coming months.