Fuel Tank Access??

[rhattersley]

Irrespective of any valves, I still don't get how siphoning can be a problem if the vent goes up, over, and exits below the tank. A siphon only continues whilst the start is still under the surface of the liquid and the end is lower than that surface. With the car the right way up and the vent full of fuel (e.g. from rolling over or accident-induced sloshing), the fuel level in the tank would have to be higher than the vent for the siphon to work. Even then, the siphon would stop once the fuel fell below the vent. With the car the wrong way up, the end of the vent will be higher than the fuel level (i.e. the bottom of the tank) so still no siphon. The same two conditions would seem to apply for the car lying on its side. What am I missing?

[peterc]

I think you will find that the stop valve is not above the highest fuel level. You can’t get that high up.
If you are inverted there’s potentially an awful lot of fuel to continue to come out before any stopping of siphon.
I certainly wouldn’t want to put it to the test.
Of course you might say being inverted has more problems.
I would admit I ran mine for years without any valve but I believe the latest IVA rules require it so I thought I would be good and comply regardless of the age of mine. It’s just peace of mind.
Peter C

[phlip99]

Many thanks Peter, all now understood.
Cheers
Phil