Aluminum foil around gas line?

[Bigsnapper43]

My father was a young man during WWii . No stamps, no money but access to lots of drip gas. One quart of coal oil to ten gallons of gas was his formula. During my driving season I put diesel using the same formula. No pop and bang!!!

[JoeCB]

Not disputing the observed stoppage due to so called "vapor lock" , but I understood that vapor lock occurred in automotive fuel systems that employed fuel pumps that drew fuel from a remote tank. When fuel in the suction line overheated and vaporized, the pump lost suction, thus no fuel delivery. On the Model A, the entire fuel delivery system is under positive pressure.. slight but no less positive. I don't see how it can become vapor locked. Perhaps within the carb itself.. maybe where the venturi "pulls" fuel from the jets... could be a problem there perhaps.
Just a thought..

Joe B

[katy]

Originally Posted by old31

Jayjay is "dollup" technical oil talk?

https://www.dictionary.com/browse/dollop

[rotorwrench]

The vapor in vapor lock is generated when the liquid fuel starts to percolate or boil. This creates a higher gas pressure in the line and severely slows any liquid fuel movement. The key is to lower the temperature enough to stop the vaporization.

In aviation, fuel is blended to change the vapor pressure to a point where it can't vapor lock. Auto fuel or mogas is not so lucky but warm weather fuel blends generally don't vapor lock easily. Cold weather fuel needs more volatility so it's cheaper to blend since it has additives to such as butane to increase vapor pressure and volatility. If a person uses winter fuel into a warm weather situation, it will easily vapor lock.

[BillCNC]

I'd try to figure out why your running so hot in the first place.


I live in the SoCal desert and in the 17,000 miles in my daily driver 31 Tudor, I have yet to encounter vapor lock. In the summer, I drive in 110* - 115* weather all the time and have never had an issue with the infamous vapor lock.


Regards
Bill

[JayJay]

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Originally Posted by JoeCB

Not disputing the observed stoppage due to so called "vapor lock" , but I understood that vapor lock occurred in automotive fuel systems that employed fuel pumps that drew fuel from a remote tank. When fuel in the suction line overheated and vaporized, the pump lost suction, thus no fuel delivery. On the Model A, the entire fuel delivery system is under positive pressure.. slight but no less positive. I don't see how it can become vapor locked. Perhaps within the carb itself.. maybe where the venturi "pulls" fuel from the jets... could be a problem there perhaps.
Just a thought..

Joe B

Well, in my case, I can assure you it's real. 95F weather, 5000 ft+ altitude, freeway speeds, car about as aerodynamic as an outhouse, and climbing - yeah, it happened. Pull to the side in the shade, open hood, surround the fuel line and carb with ice cubes from the cooler wrapped into the ever-present rag, wait 15 minutes, presto!

And I had/have engine pans in place.

[Y-Blockhead]

Let's face it. the gasoline today evaporates (boils) at a lower temperature. It is formulated for modern cars with sealed fuel systems.

Ever fill your Model A with gas and come back a week later to find you "lost" a ¼ tank?

[rotorwrench]

Altitude has a big effect on vapor pressure. This is evident in the make up of avgas. The addition of tetra ethyl lead is only part of it. The blend to control vapor pressure is the other part. 100LL is expensive for a good reason. Mogas can leave a lot to be desired and especially at higher elevations. Butane is used in winter fuel to increase volatility for starting. Even the ethanol level can change the Reid Vapor Pressure somewhat. The OP may have to check other sources of fuel to find better functionality.

[jrelliott]

I had vapor locks here in AZ at 5500 ft in elevation. Cured it by placing a 1/4" phenolic spacer between the carburetor and intake manifold. Fuel was getting to the carb, but boiling in the carb. Timing was set correct, new radiator, engine pans, and inside of engine is clean as no rust visible inside since running antifreeze . Do run MM in the gas all the time.

[HarleyFLHS]

Phenolic block helped mine quite a bit. When running the fuel is going into the engine fast enough that it doesn't boil in the carb, however if you stop and idle in traffic on a hot day, the fuel in the float bowl boils with the ethanol additive we are stuck with in California.

[Ruth]

Originally Posted by HarleyFLHS

Phenolic block helped mine quite a bit. When running the fuel is going into the engine fast enough that it doesn't boil in the carb, however if you stop and idle in traffic on a hot day, the fuel in the float bowl boils with the ethanol additive we are stuck with in California.

Me thinks California is not the only state that has ethanol in the gasoline.

[2speed]

Has anyone tried having a rubber hose line instead of steel to the carburetor? Would that offer more insulation to the gas?

[Hitman]

Originally Posted by 2speed

Has anyone tried having a rubber hose line instead of steel to the carburetor? Would that offer more insulation to the gas?

I have. It doesn't change a thing, it boils in the carb and not the line. The fuel line is only affected because the metal to metal connection at the carb transfers the heat to the line, and a rubber line doesn't affect that.

[2speed]

So where is specifically seems to boil is between the needle valve and the gas line?


With the needle closed, pressure would build to not let gas flow, but when the fuel is sucked up the venturi, the needle would open, relieving the pressure? Or does the boiling gas create bubbles that lift the float not allowing it to open? Isn't the bowl vented to atmosphere?

[stevemclark]

Originally Posted by herb concord ca

i also use mmo in my fuel tank year-round. Never had a vapor lock problem.

mmo?

[JayJay]

Originally Posted by stevemclark

mmo?

Marvel Mystery Oil. Available at fine auto parts stores everywhere, or at the river store.

[GPierce]

I use only non-ethanol fuel. Never had a vapor lock here in hot South.

[JayJay]

Originally Posted by GPierce

I use only non-ethanol fuel. Never had a vapor lock here in hot South.

An excellent point, but unfortunately many of us don't have that option. The Force (from the corn lobby) is strong.