Fuel Cell Questions

[seckerich]

Steve - I'm not sure if I understand the point you are making (and whether you are addressing my comment or the original question and picture.) All FT-3 spec cells that I am aware of use a flapper-style valve to keep fuel in the cell if the filler neck is torn off, except for the NASCAR spec cells with the two ball system. I'm sure the OP has a flapper on his cell plate. I don't think anyone considers the screw on cap as a substitute for a check valve. Are you saying that only the NASCAR-style valve is safe? Either system is designed to perform the same function, just in a different manner. The differences I see are that the NASCAR system is a bit more positive IF the car is inverted, or at least close to inverted. The balls may not close at all if the car is only resting on its side but still somewhat upright. The flappers work pretty much any time fuel tries to escape, but might not be quite as positive. Is there some info you have that the flappers don't work reliably?
Obviously, you need to have a means of keeping the fuel in the cell if a filler neck is torn off, but I assumed that was the case. And if you don't, NO remote fill is safe in a crash.

On the Dale jr fire, my understanding was that the problem was the design of the refueling neck, and that the fill plate was on the side of the cell. As I understood the design, the dry breaks and check valves were at the side of the car and connected to the cell by two aluminum necks. In the crash, the left side tire supposedly tore one or both of the necks and provided an open escape for the gas above the fill plate (since it was on the side.) When GM redesigned the system, I saw that they used an extended filler probe to plug directly into the side of the cell (i.e., a flush mount). If you have better information on that episode, let us know and I may reconsider my recommendation.

You are correct on the filler setup on the Vette. Dry break system was a good ways from the cell and his wreck was on exit of pit road so all the fuel was still in the vent and fill side of the system. Can easily be a couple gallons. I am not a big fan of flapper valves for sealing and the new trap door setup is a little better short of a real check valve system. Big problem is venting the cell for filling without either a dual setup or a descriminator valve. Personal preference but what you have will work, just not optimal. The good check systems have a light spring on the check ball to seal unless you are actively fueling.