[neilfl9]

The previous owner of my 40 Chevy street rod installed a poly fuel tank with a neat, flush, ventless motorcycle-type fuel cap that screws in and pops up and down for removal. The tank seem so be vented with a 3/8" ID fuel hose that is about 4' long, and eventually exits the trunk through the inside of the rear wheel pan. My problem is that when I try to fill my tank, I can only get about 1/4 gallon in before it overflows. To me, this is a sign that the tank is not venting properly. Can someone tell me the guidelines foir venting a fuel tank? I need to know the recommended length and diameter of the vent tube/hose and and it's location relative to the filler cap, neck and fuel tank. Sure would appreciate a knowledgeable answer.

[techinspector1]

Is the cell filled with foam to prevent fuel sloshing?

[neilfl9]

No, It is not, but what does that have to do with venting?

[techinspector1]

Wouldn't have anything to do with venting, but could explain the splash-back when filling. Being a tech inspector at the drag strip for over 50 years, I've seen thousands of these cells and never talked to anyone who has had trouble filling them. Maybe you're just trying to fill it too quickly. Slow down. The 3/8" vent is a God's plenty. It shouldn't be an issue anyway when filling. The fuel inlet is open to atmosphere when you're putting fuel in. Slow down.

[302 Z28]

I agree, the vent line is not an issue when the filler neck is open to atmosphere as in filling.

Vince