When I built my 4, way back in the late 90's,, I re-indexed the overflow port (sort of). I actually drilled a new port in the ring and plugged/shaved the originalMy old pump was re-indexed so that the overflow pipe went out the same direction as the inlet connection. However I would prefer not to re-index this new pump.
I have the special fitting from Vans but it still gets really close to the firewall when using it. The engine is out of the plane at the moment so it's easy to work with the fittings or the firewall if needed.
What is the minimum distance from anything on the engine to the firewall? Eg. from the Vans fitting to the closest point on the firewall?
Image from the other direction.
When I built my 4, way back in the late 90's,, I re-indexed the overflow port (sort of). I actually drilled a new port in the ring and plugged/shaved the original
Fast-Forward to 2020,, decided to replace the fuel pump and I did not feel like pulling apart the pump so it's essentially the same distance (or lack thereof) as in your pic, and I am using Vans overflow fitting. Not much clearance but I have seen no evidence of firewall-to-pump contact. My guess is the forces are more "rotational", around the longitudinal axis, vs left-right on the vertical.
Vans makes a special fitting for this purpose. It needs to be installed with the engine off as I recall.
https://store.vansaircraft.com/fuel-pump-overflow-plug-1-8-f-overflow-plug-1-8.html
Not mine. The photo is Steve Sampson's RV-4; G-Ikon. If you google it the website comes up. Interesting solution to the problem we all have. Mine is very close to the SS firewall but no sign of contact after many years of flying. I'm using the fitting that Van's sells and I filled it down slightly.
I am thinking of doing something like this. Shaving off the flange on the pump and then tight it down deep.