Vented gas cap?

[dartfreak75]

see photos of the sophisticated vent tube system for a 70 Dart. The cap is NOT vented and the vent tube goes through the rubber trunk floor /filler tube gasket and into........ wait for it........ the inside of the rear frame rail, where theoretically bad things won't get sucked into the tube.View attachment 1715504939 View attachment 1715504940 View attachment 1715504941

This I pretty much the exact same system I came up with except i was gonna put my fitting in the top of the tank. But I decided it would be simpler to use a vented cap. What's wrong with a vented cap versus this?

 

[67Dart273]

. What's wrong with a vented cap versus this?

Please read this thread AGAIN. All of it. Sooner or later, someone, maybe not you, is going to end up parked on a hill, maybe Seattle, maybe Francisco, maybe Podunk USA with the filler on the downhill side. Or on the left side of a crowned road. And a full tank. In the sun. And the fuel is going to puke out the VENTED cap and run down the fender.

Now it MIGHT drain some out the factory vent.................but at least it won't be running down the side of the painted car

 

[dartfreak75]

Please read this thread AGAIN. All of it. Sooner or later, someone, maybe not you, is going to end up parked on a hill, maybe Seattle, maybe Francisco, maybe Podunk USA with the filler on the downhill side. Or on the left side of a crowned road. And a full tank. In the sun. And the fuel is going to puke out the VENTED cap and run down the fender.

Now it MIGHT drain some out the factory vent.................but at least it won't be running down the side of the painted car

Mine does that with a non vented cap that's the reason I'm wanting to vent it.

 

[gm1236]

This I pretty much the exact same system I came up with except i was gonna put my fitting in the top of the tank. But I decided it would be simpler to use a vented cap. What's wrong with a vented cap versus this?

Thanks

From what I can tell, the vented cap lets pressure out but no air in. You need to get air into the tank to get the gas out. If you have suction when you open the cap your tank isn’t vented properly, unless you have a completely stock system. If you decide to vent the tube, like I did, make sure you put it as close to the top of the tube as possible. So when you fill it the fuel pump nozzle goes in pass the vent.

 

[67Dart273]

Mine does that with a non vented cap that's the reason I'm wanting to vent it.

If the cap leaks it needs to be replaced