Fuel system testing? Topping off the system blocks?

[BryanStearns]

I just finished section 27iS, the 12iS fuel system, and I'm left with a couple of questions:

• The section 27iS intro photo on 27iS-01 shows the three F-01276C-1 SYSTEMS BLOCKs' top halves installed (see photo), but I haven't installed mine or found an instruction to do so anywhere later in the fuse/finish/powerplant/avionics plans, or the PAP. Where does this happen?
• I don't have huge confidence that my fuel system won't leak - another local builder advised that "you'll have leaks, and you'll fix them, don't worry about it now". Having looked ahead at how cramped things will get later on, I'm thinking about trying to test for leaks now, by connecting the two firewall fuel connections with a loop, putting a couple gallons of 100LL in the tank (because of its helpful blue dye), and powering up the fuel pumps to run fuel through the system at pressure. Anyone done this, or have other advice?

Thanks!

 

[FlyingDiver]

28iS/U-04 Step 5.

The brake lines go in the blocks as well.

 

[BryanStearns]

28iS/U-04 Step 5.

The brake lines go in the blocks as well.

Aha! Don't know why Apple Preview didn't find those. Thanks!

 

[FlyingDiver]

Character search in PDF files is iffy at best.

 

[FlyingDiver]

And we won't talk about how many times I installed and uninstalled those blocks.

 

[Rv-12David]

With the fuel lines made and installed I capped of the tank connections and ran a temporary connection between the 2 firewall fittings. With all that in place I pressurized with air to 80lbs - about twice working pressure and let it sit. It took a few rounds of soapy water spray but the leaks were found. All fixed by tightening the fittings. Eventually it sat for a week with out loosing pressure.

As a few of the fittings become hard to reach later the sooner you install and test them the better.

 

[CTCole]

You can check the fuel system with just a very little air pressure, putting a tire inflator valve on one of the fittings that comes up through the firewall, and a nitrile glove over the filler port of the fuel tank. Just add enough air to inflate the glove- so it stands up, no more- don't blow up the tank! You don't want to put fuel into the system until you know it's intact, if at all possible.