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firewall placement of fuel return fitting

Wayne

Well Known Member
I plan on using a IO-540 with a purge valve and thus need a fuel return line back to a tank. Since I dont have the engine yet and unsure of firewall "clutter" I was wondering where to put the bulkhead fitting for the return fuel line? It would be nice to install this with the wide open spaces as I am doing the rest of the fuel system.

Thanks
 
thats what I needed

Thanks Deem - thats what I was looking for. I had actually gone to your site and couldnt find the pic I needed.

Have a great 09
 
Can anyone tell me what the purge valve is for or does? When I plumbed the Cozy MKIV with a Superior XP IO-360, I did not use one and it starts and runs just fine. I am a ways off the decision point on my RV-10, but I do plan on using an IO-540 and would like to know if I should plan on using one.
 
And sometimes act as a primary engine kill at the most inopportune time when not properly safety wired.

Yep, that was a big concern of mine.

I chose to use a different shaped/colored knob (handle?) for my purge control, and mount it slightly away from the primary engine controls.

http://aycu32.webshots.com/image/40991/2005920552533100502_rs.jpg

Chrome "T" handle to the left of the black throttle knob.

It is also recessed a bit under the panel.
 
A few notes:

The firewall bulkhead fitting should be steel, not aluminum.

Locating the fitting and its line someplace other than the lower firewall cooling air exit region is a plus...fire follows airflow.

Consider backflow. Many installs run the purge line directly to a tank, or to a fuel supply line somewhere inboard of a tank. If the hose burns off a purge line firewall fitting mounted below the tank fuel level, there is nothing to stop gravity flow of fuel into the fire. A purge line firewall penetration mounted at some reasonable height above the fuel supply is one answer (easy with an RV). The other approach is a check valve in the purge line somwhere behind the firewall.
 
A few notes:

The firewall bulkhead fitting should be steel, not aluminum.

Locating the fitting and its line someplace other than the lower firewall cooling air exit region is a plus...fire follows airflow.

Consider backflow. Many installs run the purge line directly to a tank, or to a fuel supply line somewhere inboard of a tank. If the hose burns off a purge line firewall fitting mounted below the tank fuel level, there is nothing to stop gravity flow of fuel into the fire. A purge line firewall penetration mounted at some reasonable height above the fuel supply is one answer (easy with an RV). The other approach is a check valve in the purge line somwhere behind the firewall.

Dan, excellent observations.

Check valve ----- never thought of it.

I wonder if a high loop would do??
 
I put mine up high

To avoid the gravity backflow if the line somehow broke off north of the firewall..Highly unlikely but as I had the option then why not.

Not sure what system your using but the 4 banger AFP system's purge valve is to th right of center line on top of the engine.
I basically came straight back, thru the rear baffle so my firewall hole is up high in board of the upper right engine engine mount.

Steel bulkhead fittings are available for cheap from your local hydraulics shoppe.

Frank
 
Anybody have some pictures of the firewall location for fuel return location? The links to pictures in the previous posts are dead.

Much appreciated
 
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Return

I am using an EFII system. My return line is symmetrical with supply but on the opposite side of the tunnel. Supply runs forward on the left side of the tunnel and through the firewall. Return runs forward on the right side of the tunnel and through the firewall. Both pass through the firewall below and outboard the heater vents, similar to where section 37 in the plans details.

I opted for steel fittings...
 
Anybody have some pictures of the firewall location for fuel return location? The links to pictures in the previous posts are dead.

Much appreciated

I was looking for the same thing last night. I found pictures from Carl Froelich and maybe one other builder, plus some other discussion. Carl's picture showed his return location as basically the same location as the fuel line, but mirrored on the left side of the firewall. Someone else suggested a location just below the fuel line penetration.

I'm planning to use the mirrored location.
 
Return

Here is where I placed mine. If you do use this location, be careful on how high you go as it will interfere with the engine mount. Mine cleared by about 1/8"
RV10+SDS+EFI+%2816%29.JPG
 
Here is where I placed mine. If you do use this location, be careful on how high you go as it will interfere with the engine mount. Mine cleared by about 1/8"
RV10+SDS+EFI+%2816%29.JPG

You might want to consider replacing those aluminum fittings with steel ones.
 
Returns

Yep, Plan to do that. Did not have any on hand so used these to fit.
Was only going to change the ones on the firewall. Is it recommended to change the ones in the tunnel as well?

Thanks
 
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Yep, Plan to do that. Did not have any on hand so used these to fit.
Was only going to change the ones on the firewall. Is it recommended to change the ones in the tunnel as well?

Thanks

Nah. Just best practice to use steel for fuel line fittings and to firesleeve fuel lines FWF. Everything firewall aft can be aluminum.
 
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