Fuel cell questions

[byrd]

My fuel cell from FCG came in yesterday and I got it moched up and the holes drilled to mount it(looks GREAT and fits PERFECT!), but I have a couple of questions about the fittings needed for the tank. In the pic I marked the supply and the vent, is the vent for the filler or the tank? Please excuse my ignorance, first time for me . For the supply what do I need besides the correct fittings to reduce it down to the 3/8" fuel line I'm running. I will be going to a marine sales and service shop tomorrow to get a filler cap that will be ventless(stake pocket fill like John Fabris in the faq's)
I was hopeing some of you guys that have done this before would have some helpful info for me. TIA...Randy

[nandress]

Ok, I'm just guessing here, so call me an idiot if I lead you down the wrong path.

I am assuming you are not running an in tank pump. If correct, your supply fitting should probably have some sort of tube pickup connected to the bung, right? The bung looks to be 1/4 NPT to me, so a pipe fitting adapter should work perfect, you are using flexible lines, right?

If that's the case, your vent is probably to allow atmosphere to vent off when you fill up and allow air to come back in as your fuel pump sucks off. As your filler should vent pretty well as you are fueling, you should probably be more concerned with your vent allowing makeup air so you don't end up with vapor lock and fuel starvation. In that case, attach a short length of flexible fuel line to a 1/4 NPT fitting that gets the end of the vent hose up above the highest point in the tank (think of it like a drinking straw, if you put your finger over the end of the straw in your full glass of Coke and lift up on the straw you will leave an exact length of Coke in your straw as full as your glass until you remove your finger...ah, never mind!!! ) Then at the end of that length of tubing, you should have a check valve of some kind so that you won't keep pumping gas into your tank and find out that it is flowing out and onto the ground. (I don't know what kind of check valve your tank maker has in mind, but I think the small ones made for dirt bike vented caps are the cat's meow.)

And if that doesn't help, call your tank maker!! He can tell you what he had in mind!!

[Huck]

Randy, the vent is just as described. All the trucks thru 70 had vented systems---some were vented in the cab via a line that ran up and down in the pass side B pillar. Blazers have a vent line that runs up next to the filler hose. The later models had like 3 freakin lines running up into a tube (1.5") that was mounted next to the filler access square thingy. You need a vent in the tank and that is what this is. All you need to do is attach a fitting, then a "fuel line" hose to a high point that will allow air to enter and fuel to vent in the case of an overfill. You also want this line to not allow water or dirt to enter thus a check valve similar to those used on rear ends vent lines.