Best way of fixing vapor locked carb?

Hey guys, I have a '64 International B160 w/the 304ci V8. The OEM 2barrel Holley Carb vapor locks itself whenever the engine gets even moderately warm.

From there I usually have to wait about an hour for the carb & outer engine to cool itself down before it'll start again. Needless to say this is incredibly frustrating, especially after stopping to get gas.

Is there any way to remediate this? I was planning on replacing the carb with a much more modern one, but the mounting pattern on the old carb is very irregular, and finding an adapter is proving quite difficult. (OEM mounting bracket is 3.5" deep by 5" wide)

Any suggestions would be very much appreciated. Thanks a ton for reading this and offering any help or tips you can.

 

Find a way to cool the fuel line, perhaps move it away from the engine or get the fuel pump to provide more pressure, say an electric unit.

 

1st..be sure its not vapor locking in the fuel lines...are the fuel lines close to the exhaust manifold or engine block for too long of a run?

2nd..a heat sink under the carb can help..and a non metalic spacer to move the carb up off the manifold some..

I have seen where guys will machine a thin aluminum plate to go under the carb to disapate the heat

I have also seen a shit load of clothes pins added to a fuel line to disapate heat..and tin foil on fuel lines..the list goes on

 

Ah thanks, the fuel line just hovers over the block from the valve cover over to the carb, so I'll bend it out of the way, coat it with some thermally resistant coverings. If that doesn't work I'll replace the stock fuel pump.

Any suggestions for non-metallic carb spacers? Its such an odd size, and all the ones I've seen are just aluminum.

 

Is it by chance 5 1/8" not 5"
Holley has them 3 1/2 - 5 1/8 - 1/4 thick
http://www.summitracing.com/parts/HLY-108-52/
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they used to make spacers out of a plastic called Phenolic Resin I'm sure a piece of that coud be easily fabbed that would act as a heat shield to break metal to metal heat transfer.

 

Phenolic (available at metal/plastics distributors) and similar 'plastics' (resin cured, etc.)
I've even seen hard woods used! (oak, maple, hard cherry, etc.) Machines easily, sands smooth as glass.
I'd 'scoff', but I build and fly control line model airplanes, and use hard woods a lot (mounting engines, hard points for landing gear, etc.)

Wood is good.

 

Either that or wood.....

 

Put a cool can on it and that should cure the problem,are you sure its vapor loc? never had an international to vapor-loc,just Mopars.

 

It's not usually the carb. Cool (as in not boiling) fuel fed into a hot carb will not continuously boil off for an hour. It's usually at or before the fuel pump on the suction side of the fuel system that vapor lock occurs. The pump is unable to create enough vacuum to pull the fuel from the tank. Check your lines from the pump back. A weak/old fuel pump can make the problem worse. An electric pump near the tank so the line is under pressure usually cures vapor lock problems.

 

Also check all flexible fuel lines for internal collapse and loose flaps of rubber that may restrict flow. I know this sounds stupid but it's happened to me a couple of times and the pipes looked fine externally and posed no restriction to an air line. Just a thought.

 

Used to have a Jeep that vapor locked all the time in the summer. I mounted a cheap electric pump back by the tank, and would flip the switch to turn it on when it got hot.

 

I had a fuel line drop down on the exhaust pipe at the rear of the car. Car would run fine on short trips and even long trips as long as it was moving at speed. On a longer trip if I had to sit in traffic it would vapor lock.

A clip that held the fuel line had failed. After reattaching the line no more problems.
So make sure your fuel line is also away from your exhaust pipe and muffler.

 

i thought my 62 galaxie was vapor locking also, but i read somewhere that the fuel we now try to use can percolate and disapate and real quick and almost leave a fuel bowl empty in less than 5 min.i dont know if thats true or not, but i do know this crap wont burn like the old fuel would.

 

Exactly what does that mean to you?? Does it mean that it will start right away if you give it a shot of fuel? Then it is possible.

When I was young, I was told all the same stories... a no start when warm was vapor lock. I tried all the wives tales. I had clothes pins and aluminum foil all over the fuel line from the fuel pump to the carb.

I stopped to look at an engine and it would not start. The guy with the engine said wait a sec, went into the garage and brought out a CO2 fire extinguisher. He put his cap over the carb and gave the ign. coil on the intake a long blast. He built up a pile of snow on it. When it melted he said start it up. It started instantly just like it did when cold. It was not vapor locking at all. I had a bad coil and was chasing wild geese for months. That was in 1965 and I have never seen a documented case of vapor lock since. I've read all of the stories.

A no start when warm is not always a vapor lock.

 

That's great advice too!

 

Two things
1. electric fuel pump will solve any vapor lock problem.
2. on my old travelall I had similar problems that would strand me then work again. turned out to be an dirty inline fuel filter. after the fix I bought a spare and never had to use it

 

I make carb spacers out of birch plywood.
Cut the metal line and replace it with rubber hose.
Or insulate it with black hot water insulation tubing from Lowes or HD and tape it with aluminum duct tape (not 200 mph stuff).

 

I had the same problem even with an electric fuel pump. Wrapping the fuel line with an insulation wrap fixed it. Good luck.

 

There is a fella retired from Alcoa down in PA. that is making a Cool Carb spacer that has gotten a lot of good press. In fact Dick Spadaro is stocking the ones for the 97's and 94's. He is making a bunchof different gaskets now for other makes. No smoke and mirrors here....it really works. On his truck, when checked with a laser, the engine was at 210 but his carb was at 90. The fellas name is Dennis and can be reached at 717 309 0719 FWIW.

 

As mentioned earlier in this thread, coil is more likely the culprit. However, a LOW PRESSURE electric pump will cure many ills. A high pressure pump may simply add more problems.

Jon.

 

Fuel injection!

Just kidding. I used to just wrap tin foil on the fuel lines when moving the fuel lines on something was too much of a PITA. Always worked like a charm but looked micky-moused.

 

If it is vapor lock I have read that using an electric pump WITH a return line to the tank is the hot ticket (pun intended). With a return line system the fuel is always circulating. First things first though ... verify it isn't your coil and make sure your lines are well away from a heat source/insulated.

 

I would be thinking coil also, Graham you never mentioned checking for spark, if it stalls as often as you indicated, next time check for spark, post back and let us know..

 

I have heard about "vapor lock" my whole motoring life and have yet to have anyone give me a logical explanation of what it's supposed to be.

The explanations I have gotten defy physics.

 

Same here.

 

Please explain vapor lock to me. Please explain how a bubble of air or vaporized fuel moving toward an atmospherically vented container can block a liquid under pressure in the same vessel. If this is possible how do we bleed our brakes????

Fuel can perculate (act as a heat sink, vaporize and or evaporate from the carb, or it can expand from heat and over fill the float bowl creating a flooded engine. (try running a slightly lowered float level) Fuel lines and fittings between the tank and the pump can leak air and cause the fuel pump to try to pump air, which it doesn't do well, but a bubble of air on the pressure side of the pump can not physically block the fuel from moving. Any rubber parts on the suction side of the pump need to be checked to make sure they are not collapsing due to suction.

And ford flatheads with thier fuel pumps located above the level of fuel in the tank, and on top of the heat from the engine, usually have a hard time sucking gas up hill. Other cars that have thier fuel pumps lower than or level with the median level of fuel in the tank seem not to have these types of problems.

if you need further proof that air, gas, or vapor will move readily through a fluid toward the atmosphere, pop a beer while you're thinking about it.

 

In my business we use vacuum trucks to pump water from various underground pits, tanks, vaults, etcetera. I try to think of vacuum as non existent. You are simply creating a void for the atmospheric pressure to push liquid or air to. The most you can practically depend on a vacuum pump pulling a column of water is about 30'. That's because you are limited by the atmospheric pressure that is pushing the water up the hose. If you introduce air into the column of water by drilling a 1/4" hole somehwere along it's length, it will suck air, form bubbles and the column of water will lift higher. That's because the column of water is now lighter and the atmospheric pressure will push it higher. This would seem to blow the theories of vapor lock due to gasoline boiling in the fuel line above or near the manifold. That would just make the column even lighter and easier for the pump to push.

 

I had a problem with vaporlock with my 216 .I switched to non-ethanol gas and my problem went away....PAUL

 

Hey guys, first off, thanks a TON for the responses. I've bookmarked this page just from the good advice alone. Man this is by far the most helpful forum I've ever seen, ever.

HUGE thanks to the HAMB guys!

Anyway, I followed the advise, and bought some 3/8" Fuel hose, and used that to cover the fuel line all the way down to the fuel pump.

(I should take a picture of the fuel line routing, I dont think you guys would believe it otherwise; its incredible) but it follows the engine from the oil pan all the way up in front of the block, across the valve cover then over to the carb, all within 1" of the engine. Needless to say it has PLENTY of opportunity to get hot.

I think I've cured it now, but have yet to take it on any long drives where the engine can get really hot and see for sure.

I've taken down the numbers & names of the people offering to help with the carb spacers, so if this doesn't pan out then I'll contact everybody that has offered their help.

Again, thanks a ton for all your help!!