Vapor lock-Comments-input on what you have done to correct the problem!

Whew! That is an old one, and no one ever proved this did a darn thing. Now, just think about it: wood is a natural insulator, and it cannot draw any heat away from a metal object like a fuel line. I have seen special lines with fins that did the job of dissipating heat, and often times you will see that in refrigeration applications. Under hood temperatures just soar on a hot day, and if the car is carbureted, the gasoline just boils out of the float bowls. Even the newer version of the AFB marketed by Edelbrock will vapor lock. Electric fuel pumps are used to correct this and keep the lines full of fuel, but even then, it may not be a cure.

Comments!

I wrapped my fuel lines with the asbestos like material from Restoration Supply and put a heat baffle between the fuel pump and exhaust manifold. That seems to help. Zeke

The clothes pins do help. Their purpose is not to transfer heat, they cause air turbulence around the line thereby helping to cool the line and prevent vapor lock.

Interesting!

I ran a bracket car in the mid 80s. It was a 1963 Chev, 409-small heads with a 2 barrel carb with a adapter. Car ran on a 12.70 dial in index. 3600 lbs with me in it. That was one of the best engines that was built. Had 1000+ runs on it and never pulled a valve cover. What broke the engine was good old H2O in the winter time of MI. Took 2nd place in the nationals in 87. I was having problems with vapor lock. Had a pusher fuel pump with 3/8 fuel line. In the hot humid weather, I was having this problem. I put the pins on and it actually made it worse. Then a old time drag car builder said wrap the lines with asbestos tape. That help but still had the problem. Then I incorporated a fuel return line, problem solved. WALA! car was dialed in once I solved the vaper lock problem and drive shaft problem. Something so simple, GM started putting fuel return lines on the 409s in 63. DA!

Copied from the Imp Forum.

I used my 61 LeBaron back in 1989 when it was 124 degrees to tow 5 cars from Indio to my place, 8 miles away. Because I live in the hottest place for a normal Summer day with a lot of population, I did something to my Imperial because of our weather.

1. Wrap all metal fuel lines with an outer fuel line slit length wise and tie wrapped it all.

2. I purchased for all my B engines, 413 and 440, the truck valley cover with the heat exchanger blockoffs . They do not let the exhaust heat cross under the carb and especially since, today, alcohol in gas, boils at a lower temp than gas, I have deleted the hard starting issue that comes from vapor creating a very rich condition when starting an engine.

3. At a later date, I added 2 electric fuel pumps. One at the tank and the other forward of the radiator support. It is cooler there and easy to access the filter. I use the pumps from Auto Zone.

4. I removed the mechanical fuel pump completely.

5. The removal of the mechanical pump is a somewhat anti theft device. Hide the switches, as I use 2, one for each pump.

6. I always turn the pump off just before turning the engine off so as to empty the carb as much as possible, especially if I plan to not use the car for a couple months. No clogging of carb this way from the junk in fuel today that helps ruin older cars with non pressurized fuel systems as todays injection cars.

Hope this is not confusing. Just time and a few dollars.

Never leave home w/o huge thermos of icewater. Pour on fuel line, carb, pump when gas starts boiling on hot days. Take it from former Lincoln V12 and Graham Hollywood supercharged model. There is really no cure.

I hate electric fuel pumps millions of motorists drove every day w/o them when these cars were originally on the road. Trust me. The solution lies elsewhere. Except for a few notorious vaporlockers like the Zephyr, Graham Hollywood and some Ford flathead eights (not all). Find the solution and carry icewater. Its an old trick I learned from an old redneck when I was a teen back in the 1960s.

Oh, yeah 1 more thing: r u sure its really vaporlock? Many older cars have a rubber coupling beteeen gas line & fuel pump. These rot internally. On hot days they swell up and cut off gas flow. You would

be surprised how often this part overlooked and prob blamed on pump, vaporlock etc. Check out & don t forget icewater.

In every case where I have assisted with vaporlock the fuel lines have been incorrectly routed. The most common problem is restorers wanting to install loops or S bends in the fuel line for stress relief or to make the fuel look better. The fuel line needs to be routed so that the vapor bubble can flow and not be trapped in the line.

Lozrocks the fuel line is copper and definitely has a loop in it. I’ll look into your suggestion, it makes sense.

Chuck

On 9/14/2014 at 11:22 PM, lozrocks said:

The fuel line needs to be routed so that the vapor bubble can flow and not be trapped in the line.

Yep, the highest point should be the inlet of the carb and there should be a gradient to it from the pump. Once there is a bubble in a high point, it is damnably difficult to get it out. In water lines, a burping valve is often put at such (unavoidable) points to let trapped air out.

I have never understood why people put fancy loops in fuel pipes for this very reason. The factory didn't put them there did they?