| Fuel Cell Plumbing & Vents
Hello to all GT40 forum members. This is my first post. I am relatively new to the GT40 community but I have read most all of the discussions on the forum during the past year.
I am just about to finish CAV #69 in Phoenix. The car is guardsman blue with silver stripes and has a Roush 342 with a normally aspirated 4-barrel carburetor and a ZF trans. I have done a lot of minor upgrades to the car to make it a first class street car, including reshaping the seats, water sealing, insulating and sound reduction, adding a deadman pedal, changing clutch pedal geometry, upgrades to the suspension, etc. And, I have received a lot of very timely and generous advise from Frank Catt, Tom Hughes, Jean and John at Auto Futura, Pat Chaffin, David Wagner, and others. My thanks to you all.
My last big job is to check out the fuel cells and to minimize any vapor smells around the car that are especially noticeable in Phoenix with 110 F summer days. In addition, I would also like to upgrade the basic fuel cell plumbing. I know what follows is a bit over-intellectualized, but except for adding a roll cage, the fuel system is the only easy way to make a significant change in the inherent crash safety of the car. Any specific comments about what I am doing, right or wrong, or where to get the correct parts, would be appreciated.
Basically, I plan to follow the attached drawing except I also want to add a check valve for roll over protection in the vent tube. And, I think flaps valves or another type of valves should be added to prevent the fuel from spraying out of the fuel cells if they are compressed in a crash and the filler neck is broken.
Putting a roll over check valve in the vent tube seems easy enough. Does anyone know where I can get a check valve that (1) closes when the car is up side down, (2) will allow air to travel both ways in and out, and (3) will also prevent liquid gasoline from squirting out if the car is right side up and the fuel cells are compressed?
I think I also need a flap or plunger valve inside the filler neck nipple on the tank bladder. It would need to prevent liquid from being squeezed backwards out the filler neck if the tank was compressed on impact. And, to minimize the likely hood that the filler neck will break, the metal tube from the cap down to the valve could be replace with a gasoline tolerant flexible rubber or silicone hose.
Finally I have been told that the only disadvantage of a vent to the carburetor, as shown in the drawing, is that heavy gas vapor is immediately drawn into the intake manifold when the car is started and that may upset the air fuel mixture and make the car hard to start. To fix that, a valve (electric, vacuum, bi-metal thermal ?) could be put in the pcv valve vent tube and set to NOT open until the car was started and running.
Is this enough to take care of the basic safety and all the vapor and smell problems? If I have misunderstood anything here, please tell me. Hopefully I am just reinventing the wheel and this is about how things are normally done.
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