Fuel Tank Testing

[Jerry Cochran]

I had to remove both fuel senders and reseal so am testing for integrity. The instructions for testing with a manometer are saying either 2 to 3 inches diff in water levels or 2 feet 3 inches, can't tell which. Before bothering Van's and displaying my ignorance anyone here know the answer for sure? I'd rather not blow my tanks apart, ya know...

Thanks all,

Jerry

Oh, BTW... I would never, repeat NEVER use the supplied rubber gaskets again.
I could not figure out why I'd never get a drip on the hangar floor but mysterious fuel streaks down the belly. My hangar mate pointed out that at speed the fuel vents can slightly pressurize the tanks. Fact or fiction? You decide. I took senders out, slathered proseal and replaced. Hopefully fixed.

[jsharkey]

I just finished testing my RV6 tanks.

I pressurised the tanks with a bicycle tyre hand pump connected to the Van's test valve screwed into the tank drain fitting. The fuel line fitting was capped and as a safety messure I sealed the vent pipe with a party balloon tie wrapped to the fitting. I then hand pumped the tank until the balloon inflated (not many strokes - don't know the pressure - but not much) and then tested the joints with brushed on soapy water. The only slight soap bubbles were around the filler cap and the neck of the balloon. Another good sign was that the balloon took ages to deflate - well over an hour.

The good part is that the balloon will burst long before the tank if you get over zealous with the pressurisation.

Hope this helps.

Here is a picture


Jim Sharkey

[Transporter]

Mine varied two to three inches up and down, depending on atmospheric pressure. Left each tank in test mode for four days just to be sure.

Good luck,
Mike

[AltonD]

try this thread
http://www.vansairforce.com/communit...ad.php?t=12649

[vmirv8bldr]

When using the manometer method, be sure to record the ambient temperature at the time you record the level. You want to compare readings at similar ambient temps. Doesn't need to be exact though, first thing in the morning two days in a row, barring any significant weather changes should be pretty close. Of course, if you're shop has AC, even better. Mine is not.

I used a homemade manometer. Clear tubing, colored water, sharpie marker, thermometer. I sealed everything and blew into the drain valve while depressing the valve with a finger to open it. I only increased pressure to move the water a couple of inches, then marked the water line after it stabilized, a few seconds. You see any change in level fairly quickly though. I had a small leak through the BNC connector (capacitive system) and I could notice a diffence in about 3-5 minutes.

[Dan Langhout]

The Vans instructions for the manometer test say approximately 27 inches which equates to approximately 1 psi (.975 psi depending on the density of water figure you wish to use). That's how I tested my tank and it didn't blow up! FYI, I observed approximately a 1-3/4" water height difference for a 6 degree F temperature difference (77 to 83 degrees).

[Jerry Cochran]

Originally Posted by vmirv8bldr

When using the manometer method, be sure to record the ambient temperature at the time you record the level. You want to compare readings at similar ambient temps. Doesn't need to be exact though, first thing in the morning two days in a row, barring any significant weather changes should be pretty close. Of course, if you're shop has AC, even better. Mine is not.

I used a homemade manometer. Clear tubing, colored water, sharpie marker, thermometer. I sealed everything and blew into the drain valve while depressing the valve with a finger to open it. I only increased pressure to move the water a couple of inches, then marked the water line after it stabilized, a few seconds. You see any change in level fairly quickly though. I had a small leak through the BNC connector (capacitive system) and I could notice a diffence in about 3-5 minutes.

Thanks to Bart and others who weighed in on this... I found out for sure that 27" of H2O in the manometer (that is difference between the two columns)will yield one PSI. I also believe the manometer is the easier way to see any drop in pressure as opposed to balloon. Balloons also prone to pinholes, BTW...

Hope this discussion will help others.

Jerry

[AltonD]

One last gotcha:

When you are spraying down the tank to check for rivet leaks, expect to see the manometer level fall (you are cooling down the air inside the tank).

[thallock]

Jim,

I hate to say it, but if your balloon deflated after only one hour, then I would be concerned about the tank leaking. I may be wrong, but one hour does not seem to be long enough to be sure the tank is 100% air tight. There's no way to know if the balloon deflated due to a leak in the tank, a leak in the balloon, or a temperature change. I would recommend you hook up a manometer to your tank and let it set for several days to be sure it does not have a leak.

Tracy.

[jsharkey]

Originally Posted by thallock

Jim,

I hate to say it, but if your balloon deflated after only one hour, then I would be concerned about the tank leaking. I may be wrong, but one hour does not seem to be long enough to be sure the tank is 100% air tight. There's no way to know if the balloon deflated due to a leak in the tank, a leak in the balloon, or a temperature change. I would recommend you hook up a manometer to your tank and let it set for several days to be sure it does not have a leak.

Tracy.

I checked the tank per Van's instructions by pressurizing it and using soapy water to identify any leaks. The only slight bubbles were around the filler cap and the balloon its self. Even with these the balloon was still inflated well over an hour later - at which point I removed it.

I can still do a long term test using a manometer. If I do it in the basement the temperature won't change so it'll be a good indication of any pressure loss overtime. The question is will it tell me any more than the soap bubble test? Does any one else have experience of only doing doing this?

Jim