I am planning to use the breather line for the fule return in my bus. I will remove the charcol canister from one side and return the fuel direct to the tank. The other side I will leave as a breather but vent it outside of the engine bay. My question is, are the two breathers connected? If I return fuel via one and leave the other as a vent will the fuel just pour straigh ot of the vent?
Or would it be better to block the unused vent and try and get a vented gas cap?
Oh, its a 72 bay, if that makes any difference.
Type 2 fuel tank breather
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raygreenwood
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This is one of the worst methods. First, its not good for the fuel fumes to vent straight to air. Second, this alone with no driving will lose on average, 1/2 gallon through straight evaporation of your hard earned gas money. Next...dribbling fuel from the breather ports while driving....from the top of the tank...bearing in mind that that fuel may also be warmer,....will create a huge amount of aeration (not worried about foam here)...which causes a huge amount of evaporation. In my area..with 100+ degree summers, long ago, I tracked this. Just leaving the charcoal canister hose loose is good for most of 1 gallon plus...per day....of loss while driving around. And no it is not sloshing out. You can actually see the fumes shooting from the end of the hose in hot weather. This loss will be in addition to the extra vaporization of warm fuel dribbling into the tank from up high.
You can plumb the return with no problems, back to a fuel accumulator and a "Y" right before the pump.
Leave the charcoal canister hooked up. If not for enviromental reasons...at least becauise it has absolutely no detriment to performance in any way....and lets YOU burn the fuel you payed for.
When the cannister gets full, it doesot allow much in the way of fumes out. It may pass a little by into the intake when the pressure rises...but thats it. Its a good system. Ray
You can plumb the return with no problems, back to a fuel accumulator and a "Y" right before the pump.
Leave the charcoal canister hooked up. If not for enviromental reasons...at least becauise it has absolutely no detriment to performance in any way....and lets YOU burn the fuel you payed for.
When the cannister gets full, it doesot allow much in the way of fumes out. It may pass a little by into the intake when the pressure rises...but thats it. Its a good system. Ray
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72_bay_simon
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- Joined: Tue Apr 29, 2003 8:37 am
I would have thought the plumbing the return directly back to just before the pump would cause hot fuel to recirculate, especially when stuck in traffic on a hot day. This could in theory cause a lean condition (though probably only a very slight one)
If I retain one charcoal canister and return via the other, I think I should be able to vent the tank sufficiently to prevent a negative pressure. Also living in the UK its a very rare occurance to get my tank as hot as yours might get!
If I retain one charcoal canister and return via the other, I think I should be able to vent the tank sufficiently to prevent a negative pressure. Also living in the UK its a very rare occurance to get my tank as hot as yours might get!
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raygreenwood
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Nevr been asked that question Sharkey....but one thing you shouldn't do....is plumb the vent line directly to the air cleaner 
. 
With no flame trap....it could get exiting!.
Actually, adding a charcoal canister is pretty simple and they can be had at the junkyard for less than $5 usually. The nice old style metal bodied ones can be found in one of two conditions. A) rusted out at all seams. This is what happens to a charcoal cannister that is disconnected from the engine by an owner....but not disconnected from the tank....or disconnected and plugged when its full of fuel and water vapor. The stuff just condenses on the inside and rusts. B) In nice condition, still hooked up and generally usable.
If having the original metal cannistered charcoal canister is not that important to you....then look at the watercooled vehicles. Many of them in the 80's and 90's had a cannister the identical shape, size and hook-ups as the aircooled cars did...but they had a plastic body. For a smaller version of a servicable cannister...you can get one like they used on the converticles...and put under the left front fender. Its cylindrical and looks like a refrigerant dryer.
Many times, these cannisters are fitted at either the back of the pan behind the battery area, or I thnk a few may have had them behind the fan housing on some models....and even under one of the rear fenders.
There is no reason why you could not put one concealed under the back seat. Its no more or less unsafe than a fuel line running through the tunnel.
For the hook up to the tank, it takes only a small vacuum line. You can tee in at the filler neck. That goes to the small bore intake on the cannister. The large bore inlet went to a 14mm nipple you see on a lot of the fan housings. That forces air into the cannister to aerate the charcoal saturated with fumes. It exits the other end in a 12mm or 14mm hose that goes to the air cleaner. Ray
. With no flame trap....it could get exiting!.Actually, adding a charcoal canister is pretty simple and they can be had at the junkyard for less than $5 usually. The nice old style metal bodied ones can be found in one of two conditions. A) rusted out at all seams. This is what happens to a charcoal cannister that is disconnected from the engine by an owner....but not disconnected from the tank....or disconnected and plugged when its full of fuel and water vapor. The stuff just condenses on the inside and rusts. B) In nice condition, still hooked up and generally usable.
If having the original metal cannistered charcoal canister is not that important to you....then look at the watercooled vehicles. Many of them in the 80's and 90's had a cannister the identical shape, size and hook-ups as the aircooled cars did...but they had a plastic body. For a smaller version of a servicable cannister...you can get one like they used on the converticles...and put under the left front fender. Its cylindrical and looks like a refrigerant dryer.
Many times, these cannisters are fitted at either the back of the pan behind the battery area, or I thnk a few may have had them behind the fan housing on some models....and even under one of the rear fenders.
There is no reason why you could not put one concealed under the back seat. Its no more or less unsafe than a fuel line running through the tunnel.
For the hook up to the tank, it takes only a small vacuum line. You can tee in at the filler neck. That goes to the small bore intake on the cannister. The large bore inlet went to a 14mm nipple you see on a lot of the fan housings. That forces air into the cannister to aerate the charcoal saturated with fumes. It exits the other end in a 12mm or 14mm hose that goes to the air cleaner. Ray
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72_bay_simon
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raygreenwood
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