Looping gas tank vent tube?

[alexmak]

I recently filled the full tank and it seems that I got some fuel into my charcoal canister - my vent goes up a bit (higher than tank), and then to vent canister, which is mounted next to fuel fill tube. Someone suggested to make a loop with a vent tube, so it will stop gas from getting into canister, although I'm not entirely sure in the physics of this. Any suggestions or explanations how to do this better to prevent gas from getting into vent tube?

[egchewy79]

151751

this is what I did. I had an extra brake reservoir that no one seemed to want at the time, drilled a hole in the cap and filled it with aquarium charcoal.

[65 Cobra Dude]

Alex,

I make my own charcoal canisters out of 2 inch PVC with pvc caps. I drill one hole in the top and tap it and screw in a stub toconnect to the vent tube on the tank. The other side has multiple holes open to atmosphere. I screen the ends with regular window screen using 2 pieces and angling them so the holes are smaller. I glue one cap on and fill the 2” tube with aquarium charcoal. I then screen the other side and glue on the cap. Next, I mount it to the frame behind the rear end and connect the vent tube to it. I use at least 2 loops in the hose before connecting it so it does not contaminate the charcoal with raw fuel.

Hope this helps,

Henry

[Norm B]

The best way to prevent that is, don’t top up after the pump clicks off or you see fuel in the filler pipe. Slowly adding fuel after that will fill the void space at the top of the tank and eventually blow out the vent into your charcoal canister. Looping the vent tube won’t stop that. Mounting the charcoal canister as high as possible will help a little.

HTH

Norm

[mike223]

This may not apply to you, but every one of these cars I've autocrossed, or seen autocrossed, spewed gas from the vent tube as soon as they got in an extended high-g left hand turn.

The fix for that is to route the vent tube as high as you can get it toward the passenger side, then "u" back over toward the driver's side and take it down low diagonally to the driver's side.

No charcoal filter required - the fuel that gets up in the vent tube drains back into the tank.


Ten years, I haven't found the vapors to be a problem.

[alexmak]

151751

this is what I did. I had an extra brake reservoir that no one seemed to want at the time, drilled a hole in the cap and filled it with aquarium charcoal.

Making tube going into the canister from the top may actually work, thank you

[alexmak]

Alex,

I make my own charcoal canisters out of 2 inch PVC with pvc caps. I drill one hole in the top and tap it and screw in a stub toconnect to the vent tube on the tank. The other side has multiple holes open to atmosphere. I screen the ends with regular window screen using 2 pieces and angling them so the holes are smaller. I glue one cap on and fill the 2” tube with aquarium charcoal. I then screen the other side and glue on the cap. Next, I mount it to the frame behind the rear end and connect the vent tube to it. I use at least 2 loops in the hose before connecting it so it does not contaminate the charcoal with raw fuel.

Hope this helps,

Henry

I have the same PVC canister. Thank you for your response about looping the tube

[Tbev]

151751

this is what I did. I had an extra brake reservoir that no one seemed to want at the time, drilled a hole in the cap and filled it with aquarium charcoal.

This is a great idea. Wish I had thought of it before going out and buying the PVC to make mine. Repurposing parts you won't likely be able to sell, it does the job, and actually looks better then the PVC version, cant beat that!

[J R Jones]

Alex, I have a street rod with Lexus power, including the fuel and evap system. The Lexus method is vent lines from the charcoal canister and the fuel tank to the top of the filler neck (two lines). There are no loops and it works.
jim

[alexmak]

151751

this is what I did. I had an extra brake reservoir that no one seemed to want at the time, drilled a hole in the cap and filled it with aquarium charcoal.

So I ended up a) looping the vent tube, b) replacing a canister with a spare brake fluid reservoir (awesome idea!), and c) instead of going into a canister from the bottom, rotate it so it goes into it from the top (makes charcoal change easier, supposedly).

Hope this does it.
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