For this annual I removed the stock Vans fuel selector valve for an inspection. Lots of builders substitute Andair valves, and yes, they're nice, but I had pulled this one apart when new, about 740 hours ago, and didn't find anything objectionable. Still don't.
Goes together like this:
Two details: Do not lube the nylon spindle with EZ-Turn fuel lube, or if you do, be extremely sparing..barely enough to know it's there. Even a thin film is likely to be scraped off and wind up in the downstream fuel filter, or worse, in a carb or fuel injection jet.
Second, install the o-ring into the cap with some EZ-Turn to stick it in place, then put a dab on the shaft. Now push the cap down the shaft and screw it into place without backing up. If you pull the cap up the shaft, the o-ring will pop out of the cap due to shaft friction, and there's a good chance it will not re-seat back into it recess. BTW, lube in this upper section of the valve won't hurt anything; there is no fuel flow up around the shaft.
Pulling the valve means draining the tanks. (Do that with a grounded metal defueling funnel please.) I just pull the drain valves with the tail raised to level the longeron. With the tanks empty, there is an opportunity to confirm fuel float sender calibration at low fuel levels.
Like most I ignore the float gauges until several hours into a flight, as they physically can't offer an accurate reading until the fuel level drops below the top of the inboard bay. Until then, it's all totalizer and wristwatch. However, the gauges are useful in the last stage of a long flight, to confirm the totalizer and whatever mental fuel calcs you may have running.
The check is simple. Start with the tanks dead empty. Install the drain valves. Confirm the gauges read zero or similar. Now add exactly two measured gallons to each tank, and check the gauges again.
In my case I had readings of 1.0 and 1.7 with two known gallons in each tank. I could probably tweak the EIS settings and make it perfect, but it's really close enough. The point is just to know that they're not lying, and usable fuel should be at least what the gauges show...not that I ever intend to get both of them at low at the same time.
Goes together like this:
Two details: Do not lube the nylon spindle with EZ-Turn fuel lube, or if you do, be extremely sparing..barely enough to know it's there. Even a thin film is likely to be scraped off and wind up in the downstream fuel filter, or worse, in a carb or fuel injection jet.
Second, install the o-ring into the cap with some EZ-Turn to stick it in place, then put a dab on the shaft. Now push the cap down the shaft and screw it into place without backing up. If you pull the cap up the shaft, the o-ring will pop out of the cap due to shaft friction, and there's a good chance it will not re-seat back into it recess. BTW, lube in this upper section of the valve won't hurt anything; there is no fuel flow up around the shaft.
Pulling the valve means draining the tanks. (Do that with a grounded metal defueling funnel please.) I just pull the drain valves with the tail raised to level the longeron. With the tanks empty, there is an opportunity to confirm fuel float sender calibration at low fuel levels.
Like most I ignore the float gauges until several hours into a flight, as they physically can't offer an accurate reading until the fuel level drops below the top of the inboard bay. Until then, it's all totalizer and wristwatch. However, the gauges are useful in the last stage of a long flight, to confirm the totalizer and whatever mental fuel calcs you may have running.
The check is simple. Start with the tanks dead empty. Install the drain valves. Confirm the gauges read zero or similar. Now add exactly two measured gallons to each tank, and check the gauges again.
In my case I had readings of 1.0 and 1.7 with two known gallons in each tank. I could probably tweak the EIS settings and make it perfect, but it's really close enough. The point is just to know that they're not lying, and usable fuel should be at least what the gauges show...not that I ever intend to get both of them at low at the same time.