Variance from plans - EFI/EI, return lines and location of fuel selector valve. The plans fuel system is designed for a normally aspirated parallel valve O-360; I'm building towards an EFI / EI system from SDS (their EM-5) feeding an IO-360 angle valve engine. This system has a pressurized fuel system with the fuel return flowing back to the originating tank (no sump). The Cozy plans put the fuel valve in the seat back, just like the Long EZ and notoriously difficult to operate in flight. I moved the valve to the instrument panel ("IP").

The SDS system that I'm building towards requires a return fuel line, and getting that return fuel to the correct tank means a 6-port fuel selector. Like most others, I'm using the Andair valve. In my case I got one out of a Cirrus, but it's all the same 6-port valve with permanently lubricated ceramic disks. To fit this large-ish valve in the Cozy, most put the valve on a center console, between the throttle quadrant and the foot of the instrument panel. The SDS FI means that I don't have a mix lever, so all I have is a throttle cable. With only that one control to move, I am trying to have everything on the panel, and avoid having the throttle quadrant taking up people space. That means shoehorning the fuel selector onto the panel. I think I have it done, but it did cost me 100 hours of fiddling, fitting, repairing and replacing. I ended up with a standard Andair face plate, placed low on the IP. Where the Cirrus uses an extension from face plate to valve, I trimmed that to as short as possible, while keeping the extension and the stiffness of that specialty shape. The valve itself is supported at the front by the face plate, and at the rear by a bracket shaped to the nose gear wheel well. There are nutplates on the back of the IP, inside the wheel well, and rivet nuts on the back of the valve. Note how the banjo valves were re-clocked to permit a fit under the rod for the nose gear manual extension. Valve surfaces now have a film of EX-Turn fuel lube. The banjos are safety wired using the same pattern as Andair had on the part when shipped to Cirrus.

Below is the schematic provided by SDS in their implementation guide. Mark Rieger, Cozy builder in California, was kind enough to share his more detailed schematic, with a parts call out. Mark's system is 100% AN-6, but otherwise similar to this build. My tanks have an AN-8 out and a -6 return, and so does the fuel selector valve (as above). I got frustrated with the organization of all the fiddly little AN parts, so I ended up making a paper layout, with post-it notes for each of the AN components (see below). I called out to multiple vendors before finding a combination of 3 that covered the parts I need at a price I can afford. Here is a walk through of the line sizing, as the fuel travels:

Tank to shut-off valve - AN-8 to AN-8
Shutoff to selector valve - AN-8 to AN-8
Selector valve to filter - AN-8 to 3/8th inch NPT
Filter to pump - 3/8th inch NPT to 3/8th inch NPT
Pump to filter - 3/8th inch NPT to 3/8th inch NPT
Filter to bulkhead fitting - 3/8th inch NPT to 3/8th inch NPT
Bulkhead fitting to fuel block - 3/8th inch NPT to 3/8th inch NPT
Fuel block to injectors to fuel block - TBD
Fuel block to Bulkhead fitting - 3/8th inch NPT to 3/8th inch NPT
Bulkhead fitting to selector valve – AN-6
Selector valve to tank – AN-6

Note that fuel lines are segmented for future servicing. (The more segments the more opportunities for leaks, but also the easier to service.