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Old 07-17-2011, 09:53 PM   #1
Red68
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Vapor lock question

Anyone having trouble with vapor locking in this hot weather? I have been on a couple of cruises lately and when the outside temps are 100 or more I seem to have trouble. I have heard and read about installing a "cool can" that cools the gas, do these work and if so anyone have any advice on how/where to install it? They seem pretty simple. Someone told me it was partially to blame on the ethonol that is in the fuel these days.
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Old 07-17-2011, 10:33 PM   #2
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Re: Vapor lock question

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I was having the same issues with the Red & White '70, so I put an electric fuel pump between the steel tank outlet tube and steel line that runs along the frame. No more problems. I grounded it to the frame and ran the power wire up through the same hole in the floor that the fuel line goes through, under the drivers door sill plate with the dome light & fuel sender wires and plugged it into the "IGN UNFUSED" terminal on the fuse block.

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Old 07-17-2011, 10:39 PM   #3
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Re: Vapor lock question

Cool Can...old racer trick. They would take some fuel line and coil it neatly inside a can (your choice of can). You'd probably have a connection at the bottom where the line would enter the can and another at the top of the can where it would come out and go to your carburetor. Racers packed them with ice that cooled the fuel to make it a denser mixture when the fuel and air mixed.

As you can guess, the ice would melt and have to be replaced. Reckon you'd want a drain hole or three in the bottom, huh?

I've seen plenty of fuel lines with a plethora of wooden clothes pins....the owners believed that those would help dissipate the heat. Wood is an insulator, not a heat conductor.
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Old 07-17-2011, 10:45 PM   #4
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Re: Vapor lock question

I have heard of the clothes pin trick from several old timers, my dad included. I may try the electric fuel pump idea, I have all of the wiring for it since I installed the painless kit.
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1968 C10 flatbed 307 w/ 4 spd manual (dads old ride)
1936 1/2 tn pickup, 400sb 350 turbo (partially restored)
1949 1/2 tn, needs complete restore (future project)
1969 Chevy impala 4 dr no post (wifes future car)
2010 GMC Serria 4x4 crew, leveling kit
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Old 07-18-2011, 08:27 AM   #5
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Re: Vapor lock question

i've used a piece of rubber hose split lengthwise and zipwrapped on to the metal gaslines then wrapped with aluminium foil where it was closest to headers and other heat sources// also made sure gaslines did not come into contact with engine block or intake manifolds
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Old 07-18-2011, 06:20 PM   #6
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Re: Vapor lock question

Your air/fuel ratio maybe a little on the lean side causing your motor to run a little hotter. You may try turning the air/fuel screws out a little to make the engine run a little richer. I used to have the same problem. Edelbrock 1406 carb/ 350 sbc.

Good luck!

Keith
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Old 07-18-2011, 07:27 PM   #7
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Re: Vapor lock question

The electric fuel pump thing works as long as you mount it near the tank, so it pushes. Then it is pressurizing the entire line, rather than the last 3 feet or so. The pressure keeps the bubbles from ever forming....though it is still a good idea to pay attention to routing (keeping the lines away from heat sources)
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Old 07-18-2011, 08:28 PM   #8
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Re: Vapor lock question

Quote:
Originally Posted by lil hoodlum View Post
Your air/fuel ratio maybe a little on the lean side causing your motor to run a little hotter. You may try turning the air/fuel screws out a little to make the engine run a little richer. I used to have the same problem. Edelbrock 1406 carb/ 350 sbc.

Good luck!

Keith
After I rebuilt my engine back in Dec. I have had a mechanic tweeking the carb (Edelbrock 1406), it was way too rich starting out. He leaned it out and it was better but not perfect. I was planning on taking it back to him to richen it up a little. Maybe this will fix 2 problems.

Thanks for the advice guys.
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1968 C10 LWB 327 bored 40 over, RHS heads, KB pistons, Eagle rods, Edlebrock carb & intake
1968 C10 flatbed 307 w/ 4 spd manual (dads old ride)
1936 1/2 tn pickup, 400sb 350 turbo (partially restored)
1949 1/2 tn, needs complete restore (future project)
1969 Chevy impala 4 dr no post (wifes future car)
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Old 07-18-2011, 08:33 PM   #9
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Re: Vapor lock question

Years ago I had fuel problems in hot weather. After trying everything I could think of, I tried one of those aluminum heat shields, that go between the intake and carb. I never had another problem ever again. It may or may not work for you, but it is cheap enough to give a try. To this day I run those on all my old carb equipped vehicles.
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Old 07-18-2011, 08:47 PM   #10
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Re: Vapor lock question

About 30 years ago, I was driving out through the western part of Texas, 40 miles from nowhere on a hot summer day. I saw a chevy with the hood up, and stopped to help. I told the guy it was obviously vapor locked and he needed to try and cool down the fuel lines. He got mad and cussed me out. He said he was an engineer for GM, HE designed the fuel system on that car, and vapor lock was IMPOSSSIBLE. At that point, I got back in my car, drove off and left him standing out there with a stupid look on his face.
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Old 07-18-2011, 08:56 PM   #11
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Re: Vapor lock question

I had a similar issue with my 1406. I installed a phenolic spacer under the carb and that was the end to my issue. from what i've read the 1406 is prone to heating up the fuel because the bowls or fuel is located low on the carb and takes a lot of radiant heat right of the intake. cheers, Pat
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Old 07-19-2011, 10:13 PM   #12
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Re: Vapor lock question

Your fuel pump could be failing, happened to me. Here's my (long) story:

I was taking a load of accumulated yard waste to the landfill. It was a hot day, already over 100F before noon. There was a long line on the scale. I spent nearly half an hour at idle. By the time I got to the scale the lady rang me up and the idle started to get erratic.

I pulled off the scale with an engine with no power and pinging like crazy. Then it died. I popped the hood to do a visual inspection and found nothing out of the ordinary. I got back in and got it started. I made it to the dump site and emptied the bed, and my utility trailer.

I barely got it started and I prayed I'd make it out before it completely died. There was a steep downhill followed a steep uphill on the way out. I gave it as much gas as I could to get momentum for the uphill. I should have waited, as I soon caught up to a much slower truck.

Then, I was the slower truck. Going up the hill at about 2 MPH with the gas to the floor. I decided to shut things down before I break something. I did another visual inspection, no problems. Eventually another guy, also with a trailer, stopped to help. He tried to give me a jump start but it just wouldn't crank.

Turns out a prior owner replaced the battery ground cable with an undersized one. He ended up pulling me out in a train like fashion, his truck, his trailer, my truck and my trailer.

Got it off the property which was a good thing. Allied Waste had their "help" truck watching, like a vulture, ready to charge a hefty "recovery" fee. Once my wife picked me up, we had lunch, bought a new cable, installed it, it started right up.

The story continues:

The random vapor lock continued. It's a 99% stock truck, it shouldn't do this, but I was seriously re-thinking this logic. Perhaps the fan clutch is failing? I don't like to randomly replace parts unless I know they are bad. There is a method to test the fan clutch, but the required materials to perform the test costs a little bit more than a new clutch anyway. A new clutch was installed.

No improvement, the results were the same. That is, until one night. I was hungry and I didn't want to prepare anything, and neither did my wife. I made a run for Taco Bell. While it was summer, after the sun set, it was under 105F. I got into a left turn lane and it died. I poured some emergency water on the fuel pump hoping to cool it down, no bueno.

Some people offered to help as I missed one green arrow after another. I had to decline their help, as I knew there was nothing they could do, I just had to wait it out, wait for the vapor to return to a liquid. Eventually that time came.

While cranking, the engine began to spit and sputter back to life. The green arrow was shining upon me, I hit the gas, the engine started to produce torque, but not enough HP to get the torque converter to move the truck, the light went yellow.

Just as the truck began to move, I decided to cancel my plan to turn left, I checked over my right shoulder, good, no traffic, and I went straight. The arrow went red, and I was flashed by the red light enforcement camera. I had little concern I would get busted.

The cameras are mounted in a position to catch people turning left on red, I went straight. Also, many of the cameras here have a motion camera as well, which I hoped would show that my truck had been disabled for some time. Lastly, the license plate is tucked just below the tailgate, making it nearly impossible for a clear enough photo to be of any use.

Eventually (weeks later) the fuel pump failed completely, had to get a tow. With the problem no longer intermittent, I was able to confirm a failed pump. I replaced it over a year ago and I haven't had a single instance of vapor lock since.

In hindsight, if I had checked the fuel pressure, I'm sure I would have detected a leaky diaphragm.
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Old 07-20-2011, 04:52 AM   #13
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Re: Vapor lock question

i was sure i had the vapors. my fuel line was touching the lower rad. hose and the heater hose. but it turned out to be the fuel pump. i barely made it home after dying twice popped open the hood with it running and saw the fuel pressure gauge reading flat so i thought vapor lock. weird thing is i thought it might be the gauge cause the engine ran for a good long time with no fuel pressure, way longer then i thought it could from just the fuel in the bowls.
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Old 09-17-2011, 10:46 PM   #14
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Re: Vapor lock question

Eddie H ;

nice !!!!!!!!!!!!!!!
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