A cure for vapor lock

[Logan]

I know some people say vapor lock doesn't happen, but they've never driven their car in the texas summer heat. Today it was about 110 degrees, and we were on our way back from our annual summer "hotter than hell tour" that we do every year in July. Two cars were experiencing vapor lock pretty much at the same times, one way worse than the other. I had heard a few years back from an old timer in the club that if you poured a soda on the carb, because of the carbonation in the soda, it would cool the carb down without hurting the casting.

Well after we stopped to fix a tudor (that later also experienced vapor lock) a lady in a '31 slant went to drive off and the carb vapor locked. I pulled out the choke a couple times, to dump cool gas in the bowl, loosen the gas cap and even that didnt seem to help that much. She had rubber gas line, so i couldnt put clothes pins on the line. Then i remembered what that old man once told me. so i went and grabbed a warm coke, and just poured it around the bowl and throat area. With about 3/4 of the can gone the car would rev up and act like it had never vapor locked. She took off and drove all the way to lunch without it ever happening again. After good luck with that car, about 10 miles later the '29 tudor was vapor locking bad bad bad. I did the same to her car as the first car, first with the choke, loosen the gas cap, then i loosed the tightening nut on the sediment bowl to possible let any sealed air out in the bowl. When none of this worked i grabbed another coke, and sure enough i poured it on there and within 5 seconds she was also off and going. She ended up vapor locking several more times and we ended up having to buy more drinks lol. We ended up taking off her hood and placing it in the back seat so the motor could air out and that seemed to make it cool enough to where it didnt do it anymore.

Sorry for the lengthy message, but if you ever have vapor lock symptoms this may work for you, as it worked for us. Some may not agree with the method, but it didn't crack the zenith when we poured coolant on it, and it sure does beat waiting under a tree for it to cool down.

[Jim/GA]

a plastic bottle of water will work just as well. not as messy as coke.

[700rpm]

MMO in the gas often works, but I'm not sure it could deal with 110 degrees.

[BILL WILLIAMSON]

Fun to run with the hood off! Gets lots of attention. Bill W.

[Logan]

Originally Posted by Jim/TX

a plastic bottle of water will work just as well. not as messy as coke.

It would work, but dumping water on it might crack the hot carb. I guess it's the carbonation or something in the coke that allows it to cool it down but not shock it like water would... But idk I'm not a scientist.

[Jim Brierley]

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My 601 Ford tractor often vapor locks after working it hard and then allowed to idle for awhile, gravity feed system. I merely blow in the tank for a few seconds and it is good to go again. It will run all day no matter how hard it is worked so I assume the flow of fuel keeps the lines cool enough until stopped for a rest, then the problem.

[Bob Johnson]

The last time I had the problem was in December of last year when there was a heat spell. I was using Winter gas. There is a difference between Winter and Summer gas. Winter gas has a lower vapor pressure than Summer gas. If you purchased winter gas then did not use the car until summer you would be using the wrong gas. This might contribute to the problem.

Bob

[George Miller]

On real hot days here I have to run my lawn mower with the hood off, or it will vapor lock. Hope they get rid of the crap gas.

[CWPASADENA]

MO, Try a Diesel fuel or mineral spirits. About a pint per 10 Gal. of gas. It will really raise the vapor pressure and help to prevent vapor lock. It will also lubricate the valve stems a bit.

Chris

[Mike V. Florida]

I never could understand the cloths pin thing.

[Special Coupe Frank]

As for pouring fizzy beverages under the hood, I would suggest clear seltzer / club soda instead of sugary colas - every hear about using Coca Cola (soda-pop of choice) to clean battery terminals or free-up stuck engines ?

Sugary sodas are corrosive, the the residue might cause unwanted / unintended damage...

Just a thought....

SC Frank

[steve s]

Originally Posted by Mike V. Florida

I never could understand the cloths pin thing.

I agree, Mike. But, it's even recommended as "the easiest way to prevent fuel line vapor lock" in the latest issue of Model A Times, including the explanation that the wood serves as a heat sink!! Wood is a pretty good insulator. Makes one wonder.

Steve

[steve s]

Originally Posted by Special Coupe Frank

As for pouring fizzy beverages under the hood, I would suggest clear seltzer / club soda instead of sugary colas - every hear about using Coca Cola (soda-pop of choice) to clean battery terminals or free-up stuck engines ?

Sugary sodas are corrosive, the the residue might cause unwanted / unintended damage...

Just a thought....

SC Frank

From a chemist's perspective, there's no reason that sugary stuff should be corrosive--gummy and sticky, yes. However, any carbonated beverage, including club soda should be acidic and therefore somewhat corrosive.

Steve

[steve s]

Originally Posted by CWPASADENA

MO, Try a Diesel fuel or mineral spirits. About a pint per 10 Gal. of gas. It will really raise the vapor pressure and help to prevent vapor lock. It will also lubricate the valve stems a bit.

Chris

I tried this and it didn't work for me, however a friend in our club said that it worked for him--he used between a half-gallon and a gallon of diesel per tank full. Vapor lock is reduced by lowering vapor pressure.

Steve

[Jim/GA]

Originally Posted by Logan

It would work, but dumping water on it might crack the hot carb. I guess it's the carbonation or something in the coke that allows it to cool it down but not shock it like water would... But idk I'm not a scientist.

I am not a scientist.

But I do have two engineering degrees, one of them in Chemical Engineering.

I can assure you that the carbonation does nothing to increase cooling over plain water.

I was out with a buddy of mine last summer in his A on a local club tour. He had this problem (hot day, hot engine, low speed, he was running his A/C). We poured a 1/2 liter bottle of driinking water over his hot carb to cool it off and we restarted in just a few minutes.

[BILL WILLIAMSON]

All this gobbledy goop about additives, (Most are useless!), crap gas, proper shape of gas lines, clothes pins, filter tricks, heat shields, gas line insulation, etc, etc.
As long as complete fuel system is in A-1 shape and ferrule positions are correct, side pans installed, and a decent multi-blade in place, what in hell are you to do??
Let's face it! It gets HOTTER than the hinges of Hell under the hood & gas is going to BOIL & do all kinds of unknown pressure tricks & is probably even vaporizing before it reaches the intake manifold proper. IT'S JUST THE HEAT!
Many travels on Route 66, seeing cars with hood sides removed, hoods completely off, hoods blocked open at the rear with an empty quart oil can. Chief always took the hood sides off in the summer, used old leather reins cut slightly short & a hole punched in the ends to hold the hood top down. Just hooked it in on hood catch, pulled opposite hood catch way up & hooked it in the other end. LOOKED LIKE A RACE CAR!! Some speedsters even sport factory made RACE CAR HOOD STRAPS!
Underhood heat is nothing new! I've seen battery caps MELT on '60's Chrysler products Highway Patrol cars.
Regardless of so call "tests," I still believe that the 6 blade plastic fan is the most effective on a Model A! Why else would the majority of car makers use them? I know two blade fan is a MUST on show cars.
Pardon me if I seem a little "Pi**y," I'm in the middle of filling out the "Government Packet" of forms to do with Pat's passing. I'm usually a "fun" guy!
Lets work on ways to keep the engine room cooler. In some extreme temps, we're just going to have to put up with it. Bill W.

[Mike V. Florida]

Hey Bill sorry to heat about Pat.

[Tacoma Bob]

Yup this topic will die off in the early fall...............always does. I posted a photo several years back about a little 'spiriment" I did. I took a soda can "Koozie" and slipped it over my glass sediment bowl. Ran a piece of wire across the top to hold it in place. I was traveling with three other "A"s and although none of us vapor locked whenever we did stop I measured just the tops of the sediment bowls with a thermal gun. My temp was consistently 15 degrees cooler + or - a degree.

[awander]

Originally Posted by Logan

It would work, but dumping water on it might crack the hot carb. I guess it's the carbonation or something in the coke that allows it to cool it down but not shock it like water would... But idk I'm not a scientist.

Has anyone here personally, ever, cracked a carburetor by pouring water on it?

[BILL WILLIAMSON]

Originally Posted by awander

Has anyone here personally, ever, cracked a carburetor by pouring water on it?

awander,
Nope! But I've seen Zenith bowls & covers RUST right before my eyes when rinsing off the carb dip cleaner, WEIRD!! Rusty Bill W.