fuel tank breather valve for a Convertible

[Hans Efde]

I am busy refurbishing my fuel tank. It now seems a good idea to install a fuel tank breather. Since I have a aircraft style fuel cap with funnel, the T-piece where the return connects to is gone. The fuel tank breathing hose is now mounted in the wheel well and has an open connection. Since the line is hardly higher than the fuel tank I've had regularly fuel coming out in the corners.
So it's time to install a valve. Question is what I should do. There is an expensive Mocal valve (40-50 pounds) that lets air in and out, but closes when fuel wants to pass. Alternatively one way check valves are offered. These cost less than 10pounds. Question is if they do the same job.
Does anyone have experience with one way of Mocal valves for this application?

[Rich]

I don't know what make mine is Hans but it's a two way jobbie. It works fine as long as the vent is kept clean and unblocked. Mine got blocked and caused all sorts of problems with the tank collapsing, causing cutting out and wrecking the mechanical pump. First thing I noticed was cheaper fills and shorter distances covered per tank.

I added a length of silicone pipe to the outlet and tucked it out of the way of much and debris, no problems since.

Mine is a black version of this.

[Hans Efde]

Thanks Rich,looks like a normal check valve.