Continuing Firewall Forward, 4 hours 4 screws

TLDR

• Installed the fule pump bracket
• Misc research work on fuel lines’’

Detail

Fuel pump brakcet

The fuel pump bracket for my installation is slightly different from the instruction in the KAI.

In the KAI, the bracket is supposed to be installed in a upright position. For my naviflow set up, the fuel pumps needs to have its fittings sideways pointing to the naviflow. So I need to install the bracket sideways.

The 4 mounting holes to the bracket is almost perfectly square, but with just a few millimeters offset. So they are actually a rectangle. To install the bracket sideways, I used dremel to slightly make the holes oval shape. The holes are squeezed closer horizontally, and moved further apart vertically.

Adjusting the hole took a lot of time, as I don’t want to make them too big. And in the process I broke several grommets.

When the hole and mounting bushing and screw all fit in the end, I used a multi-meter to test the continuity between the bracket and the airframe. There was none. Then I torqued down the locknuts to make it permanent.

Fuel check valve research

Naviflow check valve

On the naviflow unit, there are 2 barb fittings to connect to a check valve. Interestingly the check valve I received from Sling has AN6 fittings. I think this is probably a new revision. They used to have 3/8 hose end fittings for 915, and switched to AN6 for 916 engines. (My engine is 915 but the firewall kit I got was based on 915, that’s another issue).

So anyways, I sent a question to aeroinno to ask about my options. I think I might have to get a new check valve with the barb fittings.

Main fuel pump check valve

And for the main cross fuel pump, the KAI says I need 2 low pressure check valve (0.4-0.7 PSI) but my kits included high pressure valves (0.8 PSI). I sent a question to technical, and they confirm they must be the low pressure version. So they also needed to be replaced.

Mismatched parts in firewall forward kit

As I mentioned earlier, I am going to use 915 engine but my FWF kit is base don 916 engine. The two engines are almost identical externally but there are still some differences in installation. So I have a dozen parts I probably won’t need, and some parts missing. I am in the process of re-inventorying everything and figure out what I am missing to actually install the 915 engine.