Saturday, September 04, 2010

Fuel System Install: Firewall Forward

The fuel system is complete forward of the firewall.  The pics below are sequenced in the order that the fuel flows.  The first component installed was the gascolator, which acts as a fuel sediment trap and screen.  The fuel flows into the bowl from the top elbow and then out through a screen near the top and out through an elbow on the other side.   Note the spring-loaded valve on the bottom.  The unit is mounted on the firewall.


The auxiliary electric fuel pump is mounted on cushioned clamps to the engine mount.  I'm told it's a diaphragm type pump which offers little restriction to flow when not used.  Note the black fuel lines housed within firesleeve.  The firesleeve is capable of withstanding direct flame for up to 15 minutes.  The fit was snug between fuel line and sleeve, so I clamped both hose/sleeve via single clamp to the hose-barb fittings.

Next component installed was an in-line fuel flow sensor from Dynon.  This was installed where a fuel filter would normally go; however, I did not install the filter based on recommendation from Rans that there are issues with it being compromised by ethanol fuel additive.  First pic looking down and then up.


Next a connection is made at the rotax supplied line...

...And the that line runs to the mechanical fuel pump.  First an overview shot and pump housing closeup...

From here fuel is pumped to the bottom of the banjo junction fitting, mounted on the compensating tube.  Following pic also shows return line on top running to the gascolator.  A fuel pressure sensor from Dynon was installed where a plug was located in the fitting.  Rans indicated their supplied sensor has been shown to be erratic. 

Here is view from top, which also show the smaller two lines running left and right to each carb.


ADDENDUM:  After talking to Rans and spending several days in deliberation, I decided to redo all of the fuel line connections and clamp the fuel lines directly to the hose barb fittings.  I then safety wired the fire sleeve to the fuel lines.   Here is a pic showing the revised fuel lines in the firewall area.

ADDENDUM 2:
After further investigation and, yes deliberation, I ended up sealing the ends of all of the fuel line firesleeve with RTK high temperature silicone.  Ed at Rans had a great tip to use Formula 409 on your fingers.  This allowed you to form the silicone without it sticking to your fingers.   I've got these lines as fireproof as I'll ever get them now.

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