I am using electronic fuel injection (SDS EFI) which requires a return fuel line. I am using the wing root filter kit from Aircraft Specialty Flightlines. The recommended location for the return fuel line is close to the spar. This is especially tight when installing a bung on a quick-build tank, as the bung needs to be installed on the outside.
I decided to use the fuel bungs available via FlyEFII as the Van’s fittings are threaded for internal installation only.
I 3d printed a block to simulate the spar carry-through. There is sufficient clearance at the recommended position (but it doesn’t leave much room) so I ultimately decided to install the bung in a different location (near the vent line).
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/pxl_20230225_2154010244472241360896459910.jpg)
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/pxl_20230225_215350312860685281045617050.jpg)
The location forward of the vent line works well if the bung is clocked to clear the j-channel stiffener inside the tank.
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/pxl_20230227_1343186698418487414020008746.jpg)
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/pxl_20230227_1341364301227701101805989422.jpg)
This clocking allows a hole to sit on each side of the j-channel.
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/image_2023-02-2621_55_12_9202545971107503898715..jpg)
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/image_2023-02-2621_36_35_7843958589821821717653..jpg)
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/pxl_20230227_0501043949117903055669531996.jpg)
![](https://airplane.allanglen.com/wp-content/uploads/2023/03/pxl_20230227_0500317742028794022453101572.jpg)
I drilled the holes with grease on the drill bit (and a vacuum in place) but I still got shavings in the tank. I was able to remove these with a vacuum and a borescope.