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Charcoal Cannister
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#1
Is the charcoal canister necessary? It has been there since the car was new I am sure, and not even sure it is functional any more.
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#2
It's not necessary by any means. I removed the ones off my 72 and 70 California emissions. HOWEVER, the canister should have a line running to the gas tank to vent it so if you plug off the line after you remove it then you'll need to get a vented gas cap. You'll also want to plug the line going to your air cleaner if you use a stock air cleaner or aftermarket with the 1 inch-ish vent tube.
Well, I guess you don't NEED to get a vented gas cap but it's highly recommended since your gas tank won't have any air flow to help push the gas. You can by the standard 69-70 gas cap w/o emissions from CJPonyParts. Check this forum for discussions on vented & non-vented gas caps.

-Former 70 & 72 Mustang Owner.
-69 Torino GT, Formal Roof, 351W, Edelbrock 600 cfm, Edelbrock 351W Performer RPM intake, headers, AOD trans, dual flowmasters w/H pipe, Pertronix II Billet, 3.5 TRACLOC g/r, 15" Magnum 500s, 100A alt, aluminum radiator, electric fan, Pro-car seats, mini-starter...owned since Dec 13.
-70 Mach 1, 351W, Edelbrock E-Street EFI, VHX instrument cluster, Hooker headers, dual flowmasters, Pertronix II, 15" Magnum 500s, 150A alt, aluminum radiator, dual electric fans, Pro-car seats, mini-starter
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#3
I would like to have my cannister working but there is no place to attach it on the current air cleaner.
If I am not mistaken, vented caps are a must on our cars.

mike

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#4
the charcoal canister can be removed from the car as it will not cause any immediate issues, as long as you vent the tank.

you can vent the tank by using a earlier 1970 style gas cap that is vented to atmosphere this is assuming you plug the vapor return line at the top of the fuel tank that goes into the charcoal canistor

however the canister does provide a few useful functions on the car.

First if your fuel tank has not imploded from vacuum caused by the fuel pump sucking the fuel into the carburetor, then yes the charcoal can is working fine. 71-73 cars used non-vented fuel caps thus if the charcoal can was clogged up it would cause a vacuum to form inside the fuel tank. As the fuel level dropped the vacuum would raise, and BOOM fuel tank implosion.

1) emissions; it reduces the amount of evaporated fuel vapor in the air. you get that fuel smell if a car is sitting a long time.

2) the charcoal can acts as a filter between the air base and the fuel tank and carburetor fuel bowls, it provides a constant flow of exchanged air to the fuel tank and carb fuel bowls. this constant change of air sucks out the moisture build up you get inside the bowl and fuel tank. it reduces or eliminates internal corrosion(depends how much you drive the car) thus rust does not form inside the fuel tanks and form scale that falls into the bottom of the tank that either gets stuck against the fuel filter sock clogging the fuel inlet to the fuel line, or gets into the fuel line gets up to the carburetor and clogs all the small fuel bleed circuits.

3) since the tank is not vented when the car is sitting the fuel cannot evaporate, and will take much longer to go bad if the car sits for years.

Basically the charcoal canister is the PCV of the fuel system. the function is similar. a PCV sucks the extra vapors from the valve covers and reduces oil varnish from forming it also creates a slight negative pressure inside the engine that stops small leaks of oil. the charocal canister is located in the air base, so there is an exchange of positive and negative air pressure as you drive, the pcv is located after the carb in the intake manifold so it will always see negative pressure.

so there is an emissions aspect to the charcoal canister, it reduced the millions of gallons of fuel lost as vapor to the atmosphere its introduction improved air quality just as a PCV did the same for oil leaks and clogged up engine oil. but the charcoal can also keeps your fuel system in better condition removing moisture build up and preventing rust formation inside the fuel system.

you can also buy an elbow for an aftermarket air filter base, drill a hole in the air cleaner body and pop a hose connector into it then you will have a pcv vent connection and a fuel vapor can connection. the pcv is a controlled vacuum leak so the vent for one valve cover gets fresh air through the air cleaner base, and the other side is connected to the pcv and goes to full manifold vacuum.
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#5
72HCODE;124487 Wrote:the charcoal canister can be removed from the car as it will not cause any immediate issues, as long as you vent the tank.

you can vent the tank by using a earlier 1970 style gas cap that is vented to atmosphere this is assuming you plug the vapor return line at the top of the fuel tank that goes into the charcoal canistor

however the canister does provide a few useful functions on the car.

First if your fuel tank has not imploded from vacuum caused by the fuel pump sucking the fuel into the carburetor, then yes the charcoal can is working fine. 71-73 cars used non-vented fuel caps thus if the charcoal can was clogged up it would cause a vacuum to form inside the fuel tank. As the fuel level dropped the vacuum would raise, and BOOM fuel tank implosion.

1) emissions; it reduces the amount of evaporated fuel vapor in the air. you get that fuel smell if a car is sitting a long time.

2) the charcoal can acts as a filter between the air base and the fuel tank and carburetor fuel bowls, it provides a constant flow of exchanged air to the fuel tank and carb fuel bowls. this constant change of air sucks out the moisture build up you get inside the bowl and fuel tank. it reduces or eliminates internal corrosion(depends how much you drive the car) thus rust does not form inside the fuel tanks and form scale that falls into the bottom of the tank that either gets stuck against the fuel filter sock clogging the fuel inlet to the fuel line, or gets into the fuel line gets up to the carburetor and clogs all the small fuel bleed circuits.

3) since the tank is not vented when the car is sitting the fuel cannot evaporate, and will take much longer to go bad if the car sits for years.

Basically the charcoal canister is the PCV of the fuel system. the function is similar. a PCV sucks the extra vapors from the valve covers and reduces oil varnish from forming it also creates a slight negative pressure inside the engine that stops small leaks of oil. the charocal canister is located in the air base, so there is an exchange of positive and negative air pressure as you drive, the pcv is located after the carb in the intake manifold so it will always see negative pressure.

so there is an emissions aspect to the charcoal canister, it reduced the millions of gallons of fuel lost as vapor to the atmosphere its introduction improved air quality just as a PCV did the same for oil leaks and clogged up engine oil. but the charcoal can also keeps your fuel system in better condition removing moisture build up and preventing rust formation inside the fuel system.

you can also buy an elbow for an aftermarket air filter base, drill a hole in the air cleaner body and pop a hose connector into it then you will have a pcv vent connection and a fuel vapor can connection. the pcv is a controlled vacuum leak so the vent for one valve cover gets fresh air through the air cleaner base, and the other side is connected to the pcv and goes to full manifold vacuum.

H, this is a damn fine write up - well done - rep points coming
Don

Ohio Mustang Supply
440-949-2556

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#6
Thanks for the info. I always wondered what this did. The one on my Mustang is not attached to anything as far as I can tell and nothing bad has never happened, so figured it was not a critcial component. The one on my Bricklin (ford engine) seemed to not be hooked up (no stock air cleaner) so I removed it to make room for the crusie control.
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#7
most people rip the stuff off. on a daily driver you can imagine stuff like that would make a big maintenance difference, most of our cars are garage kept now and we drive very little so the corrosion is controlled and very little occurs now. also over 40 years all the hoses and connections fall apart or parts get changed out and there is no way to reconnect the original parts so people just leave them vented and no harm done. Unless you ever flip your car over. if you flip your car over without that canister and the line is vented fuel will come pouring out of that pipe and you could start a major fire raging until the fuel tank blew up.

the sad thing is it could happen, friend of mine had a 71 vert, he was screwing around lost control in a turn, recovered hit the curb and the car went right over, crushing the windshield traping him inside the car, amazing he wasn't killed when the windshield collapsed on him. his drivers seat back broke and he ended up in the back seat... the engine was still running, trying to get his lap belt off. fuel was pouring out of the vent line and poof fire started. the car did not burn to the ground and he got out, but that aged him many years. car was sold for parts and he gives me the stink eye when i drive my mach 1. hee hee

the canister would of restricted the fuel pouring out of the vent and it would of been more contained inside the original air cleaner as it drained. instead he had a bottle rocket of fuel shooting upsidedown all over the engine bay spraying the hot exhaust manifolds, one spark is all you need.

had he plugged the vent tube and used a vented gas cap he would of been much safer as well, the fuel would of then leaked out the fuel filler neck and out the vent of the fuel cap from the rear of the car.
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#8
72HCODE;124498 Wrote:most people rip the stuff off. on a daily driver you can imagine stuff like that would make a big maintenance difference, most of our cars are garage kept now and we drive very little so the corrosion is controlled and very little occurs now. also over 40 years all the hoses and connections fall apart or parts get changed out and there is no way to reconnect the original parts so people just leave them vented and no harm done. Unless you ever flip your car over. if you flip your car over without that canister and the line is vented fuel will come pouring out of that pipe and you could start a major fire raging until the fuel tank blew up.

the sad thing is it could happen, friend of mine had a 71 vert, he was screwing around lost control in a turn, recovered hit the curb and the car went right over, crushing the windshield traping him inside the car, amazing he wasn't killed when the windshield collapsed on him. his drivers seat back broke and he ended up in the back seat... the engine was still running, trying to get his lap belt off. fuel was pouring out of the vent line and poof fire started. the car did not burn to the ground and he got out, but that aged him many years. car was sold for parts and he gives me the stink eye when i drive my mach 1. hee hee

the canister would of restricted the fuel pouring out of the vent and it would of been more contained inside the original air cleaner as it drained. instead he had a bottle rocket of fuel shooting upsidedown all over the engine bay spraying the hot exhaust manifolds, one spark is all you need.

had he plugged the vent tube and used a vented gas cap he would of been much safer as well, the fuel would of then leaked out the fuel filler neck and out the vent of the fuel cap from the rear of the car.

Great post! Methinks Ford got it right the first time. If it calls for a
charcoal cannister you should use one. Fuel delivery is a serious
concern.

mike

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