Fuel Crossover Vent Question!

[sclow303]

I recently did some damage to the left fuel tank on my 140 during a botched clean out attempt. I ended up with a very nice, ready to go left wing that I can paint and put on. My plane is 1948 with the Right, Left and off fuel valve. The tanks that were in the plane had a crossover vent and the older style caps while the new wing has no crossover vent and a matching set of newer caps. Trying to get some guidance on what models had the crossover and what my choices are! I notice out f all the tanks for sale about 1 out of every 5 have a crossover nipple.

[6643]

Simple answer: if you do not have the "Both" position then you do not need the crossover tube. The converse is also true; "both" requires the crossover tube.

As far as I know there are no approved "newer" caps. Regardless, without the crossover, both tanks must have vented caps.

[8413]

These Neal Wright articles should answer all your questions. Don't confuse "half-vented" gas caps with full vented caps. The articles below explain the differences and where each should be used.

viewtopic.php?f=10&t=138

viewtopic.php?f=10&t=106

viewtopic.php?f=10&t=105

[sclow303]

That was a some great reading! I have both the fully vented caps and a set of the half vented caps... which were actually on a set of 140 wings I bought recently. Thanks a ton guys!