Does the charcoal canister still serve a purpose ?

[Quickstep192]

I’m beginning to put things back after what has turned out to be a years long fuel tank replacement project.

Among those things to be put back together is the charcoal canister.

My car was originally MFI converted to carbs.

Does the charcoal canister still serve a purpose? Or, can I just dead head the hose connections?

What does (did) the charcoal canister do anyway?

[super9064]

It prevents fuel vapors from polluting the atmosphere; also your fuel mixture will be leaner.

[proporsche]

Originally Posted by super9064

It prevents fuel vapors from polluting the atmosphere; also your fuel mixture will be leaner.

the front has good purpose the one at the right rear is usually removed...

Ivan

[GH85Carrera]

It can also help eliminate, or reduce gas fumes in a garage.

[EC900]

Fumes congregate in the expansion tank until engine is on then Vacuum draws fumes from the expansion tank to the char can then back into the intake.
When I removed my exp. tank, along with the oil fumes from leaks, my small 1 car garage smelled like Volo Auto Museum. But now with everything in place it just smells like an old car garage.

[chrismorse]

Shortly after bringing my new to me car home, (~500 miles), I smelled gas, popped the hood and found gas "peeing" out of a choline hose connecting the fuel tanks. Mumbling and whining about the old "SMOG" hoses, i took all the old stuff out, including the canister.
Long story short, I did a major service on the car and prepped it for my first club event.
When driving 200 miles to the event, I experienced low power on hills, some rough running and diagnosed/replaced the fuel pump, in a Napa parking lot. The problem persisted, untill i did my next fill up.
My "AH HAAA" moment came when I opened the gas door and twisted off the gas cap to the SOUND of HISSING, as air rushed back into the gas tanks, it even gave ut a "boink" sound......

The fuel tank system needs to be able to admit air, to compensate for the gas sucked out of it as the car runs. This is accomplished in almost all cars by a tank ventilation system that incorporates a charcoal, vapor capture tank that is emptied into the intake system to deal with any fuel vapors that might pollute.

This was a fairly stupid mistake for a 50 year car afficionado, past service manager, on his 77 ferrari.
Added a filtered air admission line and car ran well.

A thought for the wise.
chris

[AG81]

^
Thanks Chris.

[Quickstep192]

Thanks for the info. Your info prompted a couple of questions.

How is vapor routed to the intake. My carb’d car just has holes in the side of the K&N filter covers which seem like they’re more for show than actually functional.

I get the need to admit air so the tank doesn’t end up under vacuum, but doesn’t the tank’s vent do that?

[EC900]

If you haven’t blocked the vent hose at the tank (apx.12mm port, routes to exp. tank) then you won’t have the collapsing problem. But routing from expan tank thru the tunnel and to the char can, it then connects out from char can to the shroud. See if these two posts are any help….

Charcoal Canister Port Question??

Where does this hose go??

[E Sully]

It is an important part of venting the fuel tank, as well as reducing fumes and fuel evaporation.
The difference between factory and aftermarket comes into play here. Factory intake always has a housing that reduces intake noise and the vent hose can be routed to and contain the fumes.

Aftermarket tends to have a mostly open filtering element which would still allow fuel fumes to escape. When I had Webers on my car, I used the water shield housing and connected the vent hose to upper shield hole. It wasn't perfect at containing fumes, might have been more effective if I had brought it in the top of the cover.

[chrismorse]

crank case and tank venting to the rain hat sides. this is not as positive as the factory charcoal, shroud pressured vented stock system, but it is an effort to deal with the issue.
I will try this plumbing to deal with crank case blow by and the fuel tank vent/emission vapors.
I know this is not "smog LEGAL", but i feel this is a god faith effort to do "THE RIGHT THING", essentially at no performance/monetary penalty.

Rember the "ROAD DRAFT TUBES", that dumped all the cranckase "blow by" on the center of the slow and fast lanes????

Anyway, i am going to make an effort to burn the crank case/tank vapors.
funky old guy
c

[pmax]

Originally Posted by super9064

It prevents fuel vapors from polluting the atmosphere; also your fuel mixture will be leaner.

Not to mention all that evaporated gas wasted.

[Quickstep192]

Is there a more detailed version of this diagram? It’s hard for me to tell which hoses go where.

Just for grins, is there a better overall solution?

[E Sully]

Here is a decent one. Charcoal cannister is in the frunk, small expansion chamber under drivers side windshield cowel,




Evaporative tank in the drivers fender. behind headlight.


Connection from fan shroud to charcoal cannister, line back to air box.

[Black 993]

Originally Posted by E Sully

What EFI setup is this? I like it -- clean and sort of period correct looking.