My purpose was not exactly to change VE fuel system to total LEz system, but to replace the Weatherhead valve, and perhaps the localisation...
Personally, I don't have a problem with the firewall location for the fuel valve SO LONG AS IT TURNS FREELY! If it doesn't, you have the chance of overloading the Al tube/U-Joint system - fix it! Worst case is something breaking between positions, leaving you screwed. But I don't fly with a stiff valve, test it before launching as part of the starting process, and never move it in the air, short of a true emergency; so I consider the breakage risk essentially nill when it counts - in the air.
Part of my thinking is that I'm not attracted by the idea of running fuel forward and then back inside the plane. I guess my objection is more along the lines of the extra flow distance (and the weight of extra fuel line) rather than running fuel inside the plane, per se, which is what seems to bother some other pilots the most. A big part of my concern is the gravity head nature of VEZ system where one doesn't want to introduce any extra, needless pressure losses. A fuel pump sucking on a long, down-and-back fuel line system presents potential problems of another sort (solvable, of course).
I'll consider your sugestion and 'll lubed the valve up with a special silcon grease. Just need to find some special grease here...........
There is some special grease made just for this fuel valve application (super expensive stuff I've heard), but I can't give you a source because at that time I actually used some ultra-high vacuum silicon grease that I happened to have from another application. Subsequently, I bought some O-ring grease (for the fuel caps) that is less viscous, but I suspect generally similar to the grease that I used; although I never used it on a fuel valve. One thing about using this stuff is you always run a risk of getting a loose chunk of it in the lines or a port unless you use it very sparingly - since it won't dissolve in the fuel. Basically, I don't like the general concept of having to lube up the fuel valve for a number of reasons (one, using it tends not to get done often enough; two is the debris issue; etc.).
You change your valve to an ALLEN one. Is it the 6S122 model ? Spruce P/N 05-29500. >>They are a direct, bolt-in replacement for Weatherhead and other fuel valves<<. Is that thrue ? and easy to do ?...........
My Allen valve was almost an exact replacement for the Weatherhead except for a slightly different stem length. No big deal. Size, port locations, and mounting bolt holes were the same. "Pushyhog" here on the forum can chime about the correct part number and what he did, since he has just finished working through this whole fuel-valve issue with some off-forum input from me.
To-morrow, 'll have a full day tour at Paris Air Show...
Enjoy
Best, DeltaPop
