Deluxe Fuel Caps

I've heard complaints about the standard Van's fuel caps leaking water into the fuel tanks. Van's sells a good looking Deluxe Fuel Cap that can be installed when the fuel tanks are built, and I am wondering if this upgrade solves the water leakage problem.

Van's also sells replacement fuel cap O-rings that are aimed at solving the same problem. Is regular replacement of the o-rings a better solution?

Dave Cole
RV-7 wings

Excellent topic. Every wash, my tanks get water in them and I have tried new caps, new rings, etc, and the only satisfactory seal I have been able to get is with the 'thermos-type' caps we use on the Pitts. Problem with those is the handles stick out and look U-G-L-Y. I still use them, though.
One more problem with those standard caps was the fuel syphoning out over the wing on take-off after a top-off. Rivulets of 100LL could be seen running down the wing for some minutes after each refill. I hate that.

BTT

Any new development or discoveries??

It seems that the fault in the stock caps is the sealing surface of the flange. the caps themselves seem pretty good, but that flange has been tweaked to conform to the wing and as a result I dont think the hole in the middle is round any more. Maybe somebody could chuck them up in a lathe and fix up the bore nice and round before installation.

Steve Zicree

I went ahead and purchased a set of the Deluxe Fuel Caps from Van's. They are indeed very well made. The fill flange is machined from aluminum bar stock, complete with a machined crown radius that precisely matches the tank skin. This provides an excellent fit to the tank, and ensures that the bore of the fill neck remains undistorted. In addition, the precision compression latching mechanism operates more smoothly and positively than the stock Van's cap.

The fill flange on the stock cap is deep drawn from aluminum sheet, then further deformed to provide a crown radius that approximates the tank skin. I agree that this secondary forming operation probably distorts the bore of the fill neck where the sealing o-ring is located.

I am very pleased with the design, fit, and finish, and I expect they will perform well on the RV.

Dave Cole
RV-7 Wings

Fuel Caps Leaking

This may be a discussion in the "new caps" but, we don't have any problems with the standard caps anymore. A couple of us guys bought flying RV-6's with standard caps and they streamed fuel after fillups like the previous poster said and we went thru the new O rings and adjustments until we broke parts trying to tighten them enough to stop the leaks. Then a BUILDER told us about Fuel Lube and we slathered a coating on and haven't needed an adjustment or had a streaming cap in 2 years since....So now we put a fresh coat around the sides of the cap a couple times a year and are very happy with the caps....other than your fingers getting a little sticky when you handle them,
I did see a new "locking" cap Andair had on display that looked very nice at Oshkosh and I think I saw it listed on Vans site under new items, they were a glue in retrofit. If I left my plane outside (heaven forbid) I would have bought them.
Bob Martin

What and where can I get the fuel lube you mention, hard time getting my caps out with new black O-rings.

Aircraft $pruce. It's called EZ-Turn.

Any "heavey" lubricant should work. I coat my O-rings with lubriplate and have not had any problems.