Fuel lines-vapor lock

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barra340

barra340

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What is everyone doing to avoid the fuel line so close to the engine. My 67 is original all the way from Cali. Hard starts after it is hot and running. It has the 1 barrel 1920 set up..
 
The "fuel line mod" is a sticky in the engine section over at slantsix.org .
Basics are to move the fuel line from the fuel pump straight up and over the valve cover to about 6 inches from the carb. Then fuel filter. Make sure you leave enough room to get the valve cover off.
Frank
 
66aCUDA said:
The "fuel line mod" is a sticky in the engine section over at slantsix.org .
Basics are to move the fuel line from the fuel pump straight up and over the valve cover to about 6 inches from the carb. Then fuel filter. Make sure you leave enough room to get the valve cover off.
Frank
Click to expand...
I did this mod, and quite honestly. It's about as helpful as balls on a cow, didn't do a thing for me. What I think is needed is a heat shield under the carb, that or install a 1/2" or more spacer under the carb to help cooling. With the crap gas now days, I can see this becomming more of a problem as time goes by.
 
I use the foam tubbing that they wrap around your water pipes in your house.Some pull straps or electrical tape to hold in place.Works good and keeps my gas line cooler than without.Hope you try this?
 
The fuel line Mod Really helped me here in Arkansas. The factory rerouted the fuel lines about 75 or so and they come up from the rear of the engine.
As you noted a carb spacer is a great addition as well. I run 1/2 inch one on everything I own.
Frank
 
Split heater hose and wrap the line. It works for me and is the only remedy i have found.The boiling point of the new fuels is much lower than leaded gas resulting in the problem.
 
I'm having the same problem. I was wondering why all these slant 6's likely ran well in the olden days of leaded gas, my dad's 62 Valiant station wagon had no problems ever with it even on the hottest days, and it was routed very close to the engine. But it's the unleaded gas of 2009.

The exhaust manifold is so close to the float(right under it as opposed to any Mopar V-8 setup). When my 70 slant 6 Duster was bought in December it had the fuel line mod as described in earlier posts. It worked great in the cold of Ontario for just starting the engine up in my garage, started instantly. But once I got it on the road in late April it would idle and run well for about 10 minutes until the engine got hot. Then it would almost stall at idle and when in gear but not on the pedal,like making a turn or stopped.

It helped a bit to move the fuel line away from the engine. Then to cover it with the pipe insulation helped a little bit more. But now that we're into the real summer heat it starts to run bad very soon after startup. And starting it up is also harder now hot or cold.

I think my main cause must be that final bit of fuel line and carb in a very hot spot. I'm thinking like others that a heat shield and spacer may be the best method. Could the octane level of the regular unleaded gas be a difference too between our Canadian gas being 87 and it being maybe a bit higher and better in the US???

The Big E
 
Big E
I dont think your problem is heat soak. Heat soak is a restart condition AFTER you have run it up to temp. Then when you go to restart the engine it wont start right up (because the fuel is boiling in the carb/fuel lines) and you crank for a while or have to wait for it to cool down. Then it starts right up.
It sounds like you have a carb issue or vac leak or even dirt in your tank.
Frank
 
Don't get me wrong, I like my /6 DD. However, I think the /6 was designed by committee. The fuel pump is all the way on the other side of the engine from the carburetor.

First: I had a "vapor lock" problem that turned out to be the flex hose between the pump and the steel tank line collapsing when hot. Solved by putting a shorter length of hosing. I did not draw the hose real tight but left a little over ½ inch of give in it. No problems so far.

Second: The fuel line routing from the pump to the carb takes it along the front of the cylinder head, past the thermostat housing, and across the # 1 exhaust port. Whose idea was that? Try as I might, I can't find a route that is much safer. I made metal brackets that hold the fuel line a little farther away from these heat sources. I put high temp insulation along the line in some places where I could not get far enough away from the heat source to suit my eyeball estimates.

Clothes pins et al attached to the tubing act as a heat sink that absorbs heat from the line. The increased surface area assists in heat dissipation. It's a third world engineering trick that often works.

I haven't tried working up an intercooler for the fuel (a PS cooler looks like a good candidate), but if the situation is not corrected that is the direction I'd take.
 
72 Demon said:
Don't get me wrong, I like my /6 DD. However, I think the /6 was designed by committee. The fuel pump is all the way on the other side of the engine from the carburetor.

First: I had a "vapor lock" problem that turned out to be the flex hose between the pump and the steel tank line collapsing when hot. Solved by putting a shorter length of hosing.
Click to expand...


Bet you fuel line is collapsing because it isn't designed to handle ethanol blends. Buy fuel injection line! And get fuel injection clamps!
 
I'm having a heat soak problem with my slant. I seem to recall some of the late '70s-early '80s slant powered cars having a big heat shield under the carb. Anyone seen one of these or know where to get one?
TIA,
Dallas
 
saw one of those shields at a yard recently and decided to snap a pic with my cell.....not a very good pic but there is a pair of Gerber mulit-pliers for size reference. with markings every inch

IMG00593_w_measurements (Small).JPG
 
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