How do you stop vapor lock?

[Dick Steinkamp]

For you that believe that ethanol is a cause of vapor lock, the opposite is actually true. Ethanol boils at 173F. Gasoline starts boiling at 90-100F. In addition, gasoline is substantially easier to vaporize than ethanol.

http://www.txideafarm.com/ethanol_fu...s_and_data.pdf

Ethanol certainly has some down sides, but contributing to vapor lock is not one of them. In fact, the more ethanol in the gasoline, the LESS chance you have of experiencing vapor lock.

[tbirdtbird]

the problem is the mixture has various boiling points...blended fuels no longer exhibit the properties of the individual components...
https://tsocorpsite.files.wordpress....ol-and-gas.pdf

which states that the boiling point can range from 85 – 392°F, depending on many factors

[txkhog]

Could you add a pressure bypass line up next to the carb inlet and return to the gas tank. The bypass will keep gas circulating in the lines any vapor will be vented out the gas cap. This is what is done on some modern cars.

GDG

[tbirdtbird]

That is a very workable solution if you can arrange it. I have seen that done on several restorations, but none were As. One was an Amphicar. The problem for an A is just where would the return line go, and an electric fuel pump would have to be added for pressurization.

Another thing that we Texans do is to put the Zeniths on the shelf and roll out the Tillies. Tillies don't vapor lock even with crapahol gas. Die cast gives up the heat, cast iron soaks it up

[updraught]

From the same web site as the book, in the tech tip section:

"Hot drivability/hot restart problems are primarily warm weather problems. Today, the EPA regulates the vapor pressure of all gasoline during the summer months (June 1 to September 15 at retail) resulting in maximum permitted vapor pressures ranging from lower than 7.2 psi to 10.0 psi depending on the type of gasoline and area in which it is sold. Therefore hot drivability and hot restart problems such as vapor lock and fuel foaming have been largely eliminated (except for antique vehicles) for modern cars and trucks. All of us who drive antique vehicles with five pounds of fuel pump pressure still experience drivability issues. The alcohol in the fuel also dries out gaskets in the carburetor and fuel system.
The alcohol can also cause damage to rubber fuel lines and the rubber diaphragms in mechanical fuel pumps. We buy less than one percent of the gasoline sold in the United States so we are pretty far down on the food chain."

http://fifthaveinternetgarage.com/pd...rnGasoline.pdf

[John Stone]

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IMO the gas line is really not the problem. It is the carburetor getting too hot and causing vaporization. MMO usually works to a point. I know I never had the problem until the alcohol gas came on the market.

[Tom Wesenberg]

Originally Posted by John Stone

IMO the gas line is really not the problem. It is the carburetor getting too hot and causing vaporization. MMO usually works to a point. I know I never had the problem until the alcohol gas came on the market.

Exactly right.
My Stude and other cars I owned never had problems until the late 80's. I have some white wire wrap that I put on my Model A when I had to use the crap gas, and the white wrap did help, but wasn't a total cure. Gas without the corn crap was the total cure for the Model A. The carb on the Stude gets hot because it's right over the exhaust manifold and preheater, and the fuel today will boil in the bowl, so the intake is flooded when I try to restart the engine after a short stop at the store.

Some nice asbestos wrap on the exhaust would probably help, but the EPA, in their ignorance, has banned it. I'll have to see if there is some other kind of wrap that might help.

[Cool Hand Lurker]

I think aluminum clothes pins would help.

[1931 flamingo]

part # and source ??

Paul in CT

[emf]

How about these:

Aluminum Clothespins

[Safewiz]

Just a thought, but I had a bad vapor lock problem that stemmed from the heat from the manifold transferring to the carb. Caused the fuel to boil in the carb. I put a heat sink plate between the manifold and carb. Solved my problem. And I had a electric fuel pump as well. It was half inch thick and made out of wood.