Vapor seperator?? ????

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hardcharger426

hardcharger426

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Alright mopar guys, I have a 71 duster that has the vapor tube in the trunk. I've searched high and low on the internet with no results.
Where does the line connect to in the engine compartment?

The car was originally a six cylinder, but I bought it without an engine. The line was in the engine compartment on the passenger side. I have seen a 340 car with it connected to the 3rd nipple on the valve cover breather. I know the newer cars had a charcoal canister and big block cars have a vapor seperator after the fuel pump. 71 tech manual is no help either.

I know somebody out there has the answer.
 

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Thanks guys,

Anybody think it is a real bad idea to not use the vapor system from the engine?
The gas tank will still be hooked up to the vapor tube.

From what i'm seeing is mopar is using the crankcase to trap the extra vapors.

I really don't want to reinstall the old rusty line after installing new stainless steel fuel line around a tricky sub-frame connector.
 
The thing is, none of the 70/ later cars which have or had the vapor system, have an open vent line like the older cars (67/ earlier) had. These had a simple 1/4 tube welded into the filler neck up high in the trunk. A piece of tube connected there, went up high near the top of the quarter in an upside down "U" and back down through the trunk gasket, where it open ended inside the frame rail for protection, I guess.

So if you start removing that stuff you need to make sure you replace "what was" with a workable vent, or you may end up with a fuel siphon condition, or worse, pressure in the tank.

The other thing about that with modern fuel, running a vapor return system helps a lot with fuel boil and vapor lock
 
67Dart273 said:
The other thing about that with modern fuel, running a vapor return system helps a lot with fuel boil and vapor lock
Click to expand...

This is true but also helps keep gas fumes from building up after shutting it down on a hot day. My '70 Duster reeked like gas when I had the line unhooked and just hanging in my engine bay. Bought an old charcoal canister from a FABO member for a later A-body and hooked up the carb bowl vent and fuel tank vent to it with the vacuum line going to ported vacuum on the carb; now the smell is gone. I also don't have to worry about my car randomly going up in flames lol...

If you read the threads by slantsixdan he says how the original system like ours with the crankcase holding the vapors didn't work very well; it would cause an over-rich condition at idle and dilute the oil with gas over time.
 
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