Fuel Tank Vapor Charcoal

Don C

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I believe there's just charcoal pellets or granules with a screen to keep them in place.

 

Paul of MO

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I cut one open and it was full of activated charcoal "crumbles" under a wire mesh screen.

If yours is stinky you could cut a hole in the bottom to remove and replace the charcoal. Epoxy a thin metal patch over the opening and you should be good to go.

Looks like it can be bought at any pool supply store.

- Paul

 

mpbsr

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I cut one open and it was full of activated charcoal "crumbles" under a wire mesh screen.

If yours is stinky you could cut a hole in the bottom to remove and replace the charcoal. Epoxy a thin metal patch over the opening and you should be good to go.

Looks like it can be bought at any pool supply store.

- Paul
No smell to mine. Just figuring after so many years maybe it should be changed.

 

72HCODE

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they get gummed up with varnish, some people blow them out with fuel cleaner or carb cleaner, some throw mystery oil inside to soak then blow in carb cleaner let it soak and blow it out again, trying to loosen the charcoal pieces a little.

as long as there is some air flow through the canister your ok, if the charcoal moves that is good also.

another safety item the vapor can does is try to stop engine fire when the car rolls over.

when the car is rolled over, and the engine is running the fuel in the tank will start to blow out the top of the tank right into the vapor canister, it tries to act as a plug keeping raw fuel from blowing all over the hot engine, so if you shake the can and feel movement then the pieces can adjust position if needed, varnish will lock everything together.

 

EBSTANG

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they get gummed up with varnish, some people blow them out with fuel cleaner or carb cleaner, some throw mystery oil inside to soak then blow in carb cleaner let it soak and blow it out again, trying to loosen the charcoal pieces a little.

as long as there is some air flow through the canister your ok, if the charcoal moves that is good also.

another safety item the vapor can does is try to stop engine fire when the car rolls over.

when the car is rolled over, and the engine is running the fuel in the tank will start to blow out the top of the tank right into the vapor canister, it tries to act as a plug keeping raw fuel from blowing all over the hot engine, so if you shake the can and feel movement then the pieces can adjust position if needed, varnish will lock everything together.
...why/how would fuel ever "blow" into the into the vapor canister? I didn't think there was pressure to "blow" fuel all the way up to the canister.(unless, of course, during your roll over you rolled enough to be shaken like a paint can)

 

Jeff73Mach1

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lets say you were going to restore one of these canisters . . . could you heat it and "recharge" the charcoal before stripping and painting perhaps?

 

72HCODE

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...why/how would fuel ever "blow" into the into the vapor canister? I didn't think there was pressure to "blow" fuel all the way up to the canister.(unless, of course, during your roll over you rolled enough to be shaken like a paint can)
first the vapor can is a stop brake directly to the fuel tank.

remember the can is catching fuel vapor from the tank this occurs because fuel evaporates, it is also preventing a vacuum from occurring in the fuel tank, and it is removing moisture from the fuel tank reducing vanish and rust. it must protect against engine back fire through the carb which would ignite the fuel tank if it was directly connected to the breather.

as for a roll over which happens the fuel tank will be draining from the vapor line directly to the engine bay due to gravity. so the vapor can is suppose to try and stop off that fuel flow, modern cars have a Mercury switch and shuts down the fuel flow, it doesn't work well since many cars will catch fire in that situation.

another situation is if the vapor system is messed up and you have a closed emissions fuel cap which all 71-73 cars have, 70 is open

you create a vacuum inside the fuel tank which can cause implosion fuel can go anywhere at that point.

 
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I have not tried to wash out the varnish in the can but would suggest you try denatured alcohol. I use that when cleaning a carb and it works better that the spray carb cleaner. I take the carb off the lawn mower when it starts to act up and just soak it in the alcohol and blow it out and it looks like new takes all the varnish off and runs good again.

I would fill the can with alcohol and shake it and let it set a while and shake and let it set at least a day then pour out and let it set in sun and dry out. I bet the alcohol will look like stain when it comes out.

How many of you have found only two screws in you canister bracket on the shock tower? I think the guy the put mine on figured out that nobody would ever see that he left the bottom one out and only put the two top ones in. They are self threading and there was no sign of a screw in the bottom hole.

David

 

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Not sure if originality is a concern, but I ended up using a canister from a '96 Crown Vic. It's nice and compact, fits well in the stock engine bay.

 

mrmach1

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In the same subject I have a pop open gas cap on my 72 with this same system and when I pop open the gas cap it really pops open. It seems to be under quite a bit of pressure and I'm wondering if this is normal with this type of gas cap or is something amiss? I've never done any service work to this charcoal canister and could that be part or all of my problem if indeed I have a problem at all. I would appreciate any input from all of you there is a great wealth of knowledge in this forum and I like to take advantage of it. Thanks.

 
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OMS

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Your vapor housing vent on top of the tank is most likely plugged up

 

72HCODE

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the oem is a metal cap with a vent. same diameter lock ring and gasket as the fuel sender. there is a 90 degree fitting on top that connects to the vapor return line rubber to hardline to the engine firewall.

the vent can be clogged or the hardline can be clogged up to the vapor can.

 

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Clogged or simply pinched, it's a very small diameter tube that runs from the tank forward.

 

OMS

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Your vapor housing vent on top of the tank is most likely plugged up
Don is that the round plastic cap on top of the tank?
It is metal but yes on top of the tank

Usually it gets plugged - the hole is not very big in the housings tube

Disconnect the rubber line above rear end

Blow both to the canister, then blow to the tank - that will tell which way to go

 

mrmach1

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Ok my mistake I thought the tank you were referring to was the charcoal canister not the fuel tank. So I'm going to test the vapor vent housing and line on my car's fuel tank and inspect the same for blockage. Thanks for all of your help.

 
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