I had previously lubricated the standard Vans brass valve with a very thin film of EZ Turn. It was fine initially, but over time it became difficult, I think more so than a valve assembled dry. So, given its non-performance, coupled with the bad habit of clogging fuel controls, henceforth I'm consigning EZ turn to some dark corner, perhaps never to be seen again.
This time the valve went back together with a very thin film of Krytox on the Delrin spool. Bill Lane investigated and recommended Krytox for fuel cap o-rings, for which it has proved to be wonderful. At this time the valve operates like butter. I'll report in a year.
The interesting point was the stem o-ring. I suspect it gets overlooked a lot. On close examination, it appeared to not be in full contact with the stem under all conditions, having become a bit hard, squared in cross section, and shrunken. See the photo. I'm pretty sure they started life as the same size.
Here's the thing...a leaky o-ring has the potential to allow sucking air into the fuel system prior to the boost pump. It would also need to leak past the spool-to seat contact, which is not inconceivable. A few times in the past year I've seen random fuel pressure reductions during steep climbs, with no obvious cause, boost pump on or off. Well, air bubbles will do it. We'll see how she does in the coming months.
Yes, I know Andair valves are popular...
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This time the valve went back together with a very thin film of Krytox on the Delrin spool. Bill Lane investigated and recommended Krytox for fuel cap o-rings, for which it has proved to be wonderful. At this time the valve operates like butter. I'll report in a year.
The interesting point was the stem o-ring. I suspect it gets overlooked a lot. On close examination, it appeared to not be in full contact with the stem under all conditions, having become a bit hard, squared in cross section, and shrunken. See the photo. I'm pretty sure they started life as the same size.
Here's the thing...a leaky o-ring has the potential to allow sucking air into the fuel system prior to the boost pump. It would also need to leak past the spool-to seat contact, which is not inconceivable. A few times in the past year I've seen random fuel pressure reductions during steep climbs, with no obvious cause, boost pump on or off. Well, air bubbles will do it. We'll see how she does in the coming months.
Yes, I know Andair valves are popular...
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