Vapor lock Question

[edhd58]

I was just setting here going through post and ran across a "wont start when hot" one. It made me think of my "it vapor locks when hot hot" issue.

I was wondering if a setup like what is used for EFI would work. An electric pump feeding the carb, BUT, a return line to the tank so the fuel is constantly flowing and therefore maybe cooling when it got back to the tank and away from the engine heat?
I know the actual system isn't THAT simple but that was just a quickie explanation.

Again I was just wondering.

[50fordcoupeman]

How about an electric as a back up? I use both on my avatar.

[Ken/Alabama]

An electric fuel pump mounted close to the tank will cure that problem. Today's gas tends to boil with the heat from the engine when it's shut down. My Zephyr runs great but if I stop for an hour or so it will crank but will die. I can remove the gas cap and blow on the tank to push gas to the carb and it will fire right up. When the weather cools off its not a problem. The hot weather is the only time it causes a problem.

[AnthonyG]

a non metallic non heat transferring spacer at least a 1/2" between intake & carb. thicker is better. Stops the vapor lock blocking engine heat transfer to carb.

[scicala]

Originally Posted by AnthonyG

a non metallic non heat transferring spacer at least a 1/2" between intake & carb. thicker is better. Stops the vapor lock blocking engine heat transfer to carb.

Vapor lock is not a carburetor issue. The issue is too much heat in the fuel line and/or fuel pump, so the fuel vaporizes and can't be pushed to the carburetor, so no fuel in the carb equals no run. An electric fuel pump will cure the issue if absolutely needed.
A spacer under the carb will help keep fuel in the carb from boiling after the engine is shut off. The spacer has noting to do with preventing vapor lock though.


Sal

[G.M.]

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Originally Posted by edhd58

I was just setting here going through post and ran across a "wont start when hot" one. It made me think of my "it vapor locks when hot hot" issue.

I was wondering if a setup like what is used for EFI would work. An electric pump feeding the carb, BUT, a return line to the tank so the fuel is constantly flowing and therefore maybe cooling when it got back to the tank and away from the engine heat?
I know the actual system isn't THAT simple but that was just a quickie explanation.

Again I was just wondering.

It won't vapor lock with a SMALL fuel return line after the pump. You need an
orfice to control the rate of return. To much return and you run out of gas
at higher speeds. G.M.

[JSeery]

I believe that were several threads on fuel return setups a couple of years ago on the HAMB.

[edhd58]

Originally Posted by JSeery

I believe that were several threads on fuel return setups a couple of years ago on the HAMB.

Thanks JSeery, I'll look there too.

I was also wondering if a return line after the mechanical pump on the engine would work or if the mechanical wouldn't move enuf fuel?

[Tinker]

Originally Posted by edhd58

I was just setting here going through post and ran across a "wont start when hot" one. It made me think of my "it vapor locks when hot hot" issue.

I was wondering if a setup like what is used for EFI would work. An electric pump feeding the carb, BUT, a return line to the tank so the fuel is constantly flowing and therefore maybe cooling when it got back to the tank and away from the engine heat?
I know the actual system isn't THAT simple but that was just a quickie explanation.

Again I was just wondering.

So to me it's about which pump your using. The cheaper push/pull pump won't be successful in this idea. To me.


You can totally do this and the pump I'd use is a rotatory pump like a carter. You will have to also do a check valve to keep the pressure going to the carb and not going back to the tank. Bruce Lancaster had a schematic for installing a carter. The push/pull units that when off does/will let fuel go back into the tank or flow freely... (which is why push/pulls are popular to "prime" your car and still run a mechanical pump, rotatory carter type pump will not flow back to the tank freely) it's "pressurized".


What did people in the 30-40-50-60s do ever? How did they run with the issue of vapor lock? Maybe it's just a fuel issue. Too combustible. Think there was a thread a bit back about mixing kerosene with the higher octane fuel or maybe not.


Lots of factors, for me vapor lock isn't one of them in a few different climates. Just lucky I guess. Clean block, timing, and a good radiator.

[blucar]

[

What did people in the 30-40-50-60s do ever? How did they run with the issue of vapor lock? Maybe it's just a fuel issue. Too combustible. Think there was a thread a bit back about mixing kerosene with the higher octane fuel or maybe not.


I put an electric fuel pump, in my '36, mounted near the tank in 1953. Any time my Ford started to act up during hot weather, I'd reach down and flip the electric pump switch on until the problem went away.

EFV8's have been infamous for vapor lock from the get-go. Prior to buying my '36 in 1952 I had a '41 Ford, when the weather got hot it would vapor lock, never had a vapor lock at 20 below zero.
I owned several Chevy's before I bought the '41 Ford. The Chevy's of the '30/40's had a lot of built in problems, however, none of which were vapor lock. The location of the fuel pump, low on the right side of the engine and the carb mounted high and to the side of the block did a good job of reducing heat buildup in the fuel system.

[ford38v8]

Originally Posted by blucar

[ What did people in the 30-40-50-60s do ever? How did they run with the issue of vapor lock?...

They did what James Cagney did to Jean Harlow in The Public Enemy: Half a grapefruit in the kisser (fuel pump) works every time!

[Tinker]

,,,


.

[FLTHDCPE]

I really do believe that the type of fuel ( Ethanol/Octane Rating) that we are finding at the pump these days is causing most of our "fuel problems" You have to go into the search mode to find the good stuff.! The addition of an electric pump definitely helps.!

[revkev6]

I fixed my hot fuel issues by blocking the exhaust crossover in the intake. my fuel was boiling in the float bowls. engine would stall after warmup at anything over 80 degrees. open the throttle plates and nothing but vapor rising out of the carbs. blocked it and she's been great. takes a couple minutes to get warm but that's a small price to pay.

[Tinker]

Originally Posted by revkev6

I fixed my hot fuel issues by blocking the exhaust crossover in the intake. my fuel was boiling in the float bowls. engine would stall after warmup at anything over 80 degrees. open the throttle plates and nothing but vapor rising out of the carbs. blocked it and she's been great. takes a couple minutes to get warm but that's a small price to pay.

I'm a believer of this and have done it in hot climates with great success. Takes a 10-15min to get up to temp so your pulling the choke for the first few miles.



I just made up some lite tin shims with ears to remove. Doesn't do anything for the fuel pump heat but when your running how long does the fuel sit in the pump? Every little bit helps. Easy to try and doesn't hurt anything.

[tubman]

I had a 'stock '51 Ford when I was in high school in the '50's. It would occasionally vapor lock on hot days. I had a couple of "Hilex" jugs (remember them?) filled with water on the floor in the back seat. If I had a vapor lock, I'd pull out one of the jugs and slowly pour about a quart of water over the fuel pump. Worked just about every time (really hot days required a second application). I don't know where I learned what to do; I think it was probably common knowledge back in those days.

[drolston]

Did the same thing in those days on my '35 coupe, except I put a shop rag on the pump to hold the water in contact. Flip the rag and add water every few minutes. Then I put one of those clattering Bendix electric fuel pumps on the firewall. That ended vapor lock problems and helped when I ran out of gas, - which was fairly often with a non functioning gas gauge on a part time grocery bagger salary.

[tubman]

The grapefruit thing would probably work, but the Hilex jugs full of water were a LOT cheaper. I think grapefruit were about $.25 apiece, even back then.

[supereal]

More often than not "vaporlock" is not a fuel problem, but a weak or failing ignition coil. If the coil is allowed to cool, the internal resistance lessens and the spark increases. The voltage drop caused by the starter starves the ignition system, making the hot start problems even worse. If your coil is old, send it to Skip Haney and you will be amazed how much your vehicle performance improves, and "vaporlock" disappears

[blucar]

Originally Posted by supereal

More often than not "vaporlock" is not a fuel problem, but a weak or failing ignition coil. If the coil is allowed to cool, the internal resistance lessens and the spark increases. The voltage drop caused by the starter starves the ignition system, making the hot start problems even worse. If your coil is old, send it to Skip Haney and you will be amazed how much your vehicle performance improves, and "vaporlock" disappears

Super-- Is spot on with his comment about a bad coil causing what appeared to be fuel starvation.. Been there done that, poor voltage to or from the coil can mimic a fuel delivery problem.


During my teens I worked in and around a Ford dealership in Eastern Idaho. One of the items that was a part of a tuneup was to check the fuel system for proper delivery which commonly was the fuel pump. On a regular basis we would remove the fuel pump and fuel pump stand, checking the base of FP stand to make sure it was flat. It was very common to find that the constant upwards push of the fuel pump rod bent the ears of the fuel pump stand down, thereby reducing the amount of travel for the push rod..

We would clamp the fuel pump stand into a vise, get a large mill file and file the base flat... Amazing how something as simple as a bent mounting surface could effect the performance of the fuel pump.
Another thing that can effect fuel delivery is an un-vented fuel cap. Don't laugh, I have encountered this problem on many older cars, one of which was a '56 pickup that was being driven by a Certified ASE mechanic. The outfit came rolling into a road side rest. The drive asked if I had a phone, responded that I did. I asked if I could be of help. The driver replied that the outfit was driving him and the other mechanics at his shop nuts with it's constant stalling.
We opened the hood and I saw a HEI ignition being feed power via the original in-line ballast resistor. I noted that the fuel cap looked new, removed same and noted that it was un-vented..
The ASE mechanic had no idea what I was talking about.