fuel filler problems
The vent line has nothing to do with filling the tank. What I mean by that, is that if you sealed the filler neck against a nozzle and depended on the tank vent it would build pressure
The way these work (at least on the fillers I've seen) is that there is a divider inside the filler neck nearly the full length. It probably should have been longer, and maybe should have had a deflector inside the neck to insert the nozzle UNDER. The upper part of the divider is for air coming back up the filler neck as the fuel cascades down the "under" part.
I also believe much of this is because of high pressure stupidity on the part of gas stations. There's at least one here locally I simply don't go to. At the time, it "kicked" the nozzle it had so much pressure. Felt like a high pressure hose. It puked all over a couple of my vehicles. I have a 69 filler neck I'll try 'n get photos
Some photos of a 69
Below, the complete unit. Vent is 1/4 tube, comes out near the top of the neck, up high against the inside top of the rear quarter, then bends down and follows the neck, down into the frame rail, where it simply open ends. You can see the bottom of the divider in the main neck sticking out at the bottom. It is leaning here towards how it sits in the car, except moreso. The gasket sits flat on the trunk floor, so the "U" in the vent line and the gasket are both pretty much level as it sits in the car
Below, the bottom end. The lower part below the divider is gas flow, air going back out is in the top half. The divider ends about?? 10" from top of filler
Below, a view through the filler neck. This is distorted, as the divider appears to come close to the top, but again, it ends some 10" or so from top. Fuel is in lower section as this is slanted, the air at top in this photo
A good view of the vent. These seem to work well, and are simple. These use a sealed unvented cap, so if you REALLY got it full, and parked on a sidehill with the filler on the downhill side, worst that "should" happen with a proper sealing cap, is that fuel would siphon down the vent, drain out the frame rail, and onto the ground. The top cap area forms a "vacuum break" and as soon as the level would reach the vent tube, the siphon would stop
Below another view of the bottom end. Fuel is lower, air is upper. You can see fuel section is somewhat larger
The vent line has nothing to do with filling the tank. What I mean by that, is that if you sealed the filler neck against a nozzle and depended on the tank vent it would build pressure
The way these work (at least on the fillers I've seen) is that there is a divider inside the filler neck nearly the full length. It probably should have been longer, and maybe should have had a deflector inside the neck to insert the nozzle UNDER. The upper part of the divider is for air coming back up the filler neck as the fuel cascades down the "under" part.
I also believe much of this is because of high pressure stupidity on the part of gas stations. There's at least one here locally I simply don't go to. At the time, it "kicked" the nozzle it had so much pressure. Felt like a high pressure hose. It puked all over a couple of my vehicles. I have a 69 filler neck I'll try 'n get photos
Some photos of a 69
Below, the complete unit. Vent is 1/4 tube, comes out near the top of the neck, up high against the inside top of the rear quarter, then bends down and follows the neck, down into the frame rail, where it simply open ends. You can see the bottom of the divider in the main neck sticking out at the bottom. It is leaning here towards how it sits in the car, except moreso. The gasket sits flat on the trunk floor, so the "U" in the vent line and the gasket are both pretty much level as it sits in the car
Below, the bottom end. The lower part below the divider is gas flow, air going back out is in the top half. The divider ends about?? 10" from top of filler
Below, a view through the filler neck. This is distorted, as the divider appears to come close to the top, but again, it ends some 10" or so from top. Fuel is in lower section as this is slanted, the air at top in this photo
A good view of the vent. These seem to work well, and are simple. These use a sealed unvented cap, so if you REALLY got it full, and parked on a sidehill with the filler on the downhill side, worst that "should" happen with a proper sealing cap, is that fuel would siphon down the vent, drain out the frame rail, and onto the ground. The top cap area forms a "vacuum break" and as soon as the level would reach the vent tube, the siphon would stop
Below another view of the bottom end. Fuel is lower, air is upper. You can see fuel section is somewhat larger
