Fuel vapor line/charcoal canister

[Steve340]

I am not sure how the charcoal canister works. The overfill limiting valve is most likely pretty important.
I am guessing it is some sort of one way valve.
But you would not want to connect that tube that runs from the vapor separator to the engine bay directly to the manifold vacuum.
You would then have the petrol tank connected directly to the engine which would affect the way the engine runs and the vacuum could collapse the fuel tank. A backfire could blow back direct to the fuel tank and ignite the gas fumes and cause a major fire.

 

[brotow]

I have a canister from a 74 Challenger if you need it.

 

[Steve340]

If this is any help.
The 1971 system the engine bay pipe from the vapor separator connects to the air in to the engine for the PCV system.

 

[Dchase3]

If this is any help.
The 1971 system the engine bay pipe from the vapor separator connects to the air in to the engine for the PCV system.

Interesting. I’ll have to try and find a diagram for that and see how it was done on a 71. Still trying to determine if I should just cap it or run it through carb or PCV system.

 

[Dchase3]

If this is any help.
The 1971 system the engine bay pipe from the vapor separator connects to the air in to the engine for the PCV system.

I have a pcv valve on the driver side valve cover that runs to center port of carb and a breather on the passenger side valve cover. Could I change the breather to a breather with a nipple and run the vapor line to that ?

 

[Steve340]

Yes that would be fine I think.
I am only speculating but if you cap that line the fuel tank which has to see atmospheric pressure to work correctly - you "may" get the systems of a blocked vent. After a few miles the fuel pump can suck the tank in or the car runs out of fuel.

 

[Dchase3]

Yes that would be fine I think.
I am only speculating but if you cap that line the fuel tank which has to see atmospheric pressure to work correctly - you "may" get the systems of a blocked vent. After a few miles the fuel pump can suck the tank in or the car runs out of fuel.

some people say theyve capped it without issues (with vented gas cap) and others claim to have had issues after capping it. Also seems like running dirty fuel vapor air into the breather might not be a great idea either. Idk.

 

[Steve340]

No I don't think so.
The PCV will create a slight depression in the tank that should deal with any vapours created by evaporating/expanding fuel.
After all the engine is gulping the same dirty fuel vapours via the carburettor and fuel pump.
What vaporises off the fuel will be free of particulate the PCV doesn't have enough suck to bring any particulate matter from the fuel tank all the way to the engine.
You may be over thinking a little - however it would pay to make sure that long uncapped line is clear before you hook it up.
If you are worried you could install a course filter like the factory did. The 3 nipple breather had a course horse hair filter in it.

 

[Steve340]

If you are getting liquid fuel up that line something is wrong.
A smell of fuel in the engine bay wafting out of the open line is one thing but not raw or liquid fuel.

 

[Dchase3]

If you are getting liquid fuel up that line something is wrong.
A smell of fuel in the engine bay wafting out of the open line is one thing but not raw or liquid fuel.

No liquid fuel. Just fumes. And mostly while driving. When sitting nothing