Firewall Forward, Part 3

After enlarging one of the firewall openings from 1" to 1.375" for the d-sub connector on the engine wiring harness, it was time to fabricate a custom pass through. 

As previously mentioned, I am using the Alumiweld product (from Harbor Freight) to "braze" the tube stock to the sheet stock.

Shown below is a picture of my first attempt at the two part pass through assembly.  I ended up junking this one as the notch in the lower left corner of the male part just bugged me, so I made another one.

Version 2 of the pass through.

Final installation of the pass through with number 8 machine screws, washers, stop nuts and a new longer rivet (at the 6 o'clock position).

Another view, which also happens to show the existing throttle cable hole in the firewall to the lower left.

The next series of tasks involves finalizing the firewall for the Viking engine installation, which includes changing some of the Rotax "features".  Among them is this array of holes which allows the passage of warm air from the radiator of the Rotax installation.  Not needed for the Viking, I embarked upon the mission of covering it up with another piece of stainless steel.

I will also point out that I did remove the engine after finishing the preliminary installation (see Firewall Forward, Parts 1 & 2), so no, these pictures are not out of order, despite what it might seem.

Foreground picture of the fabricated stainless cover plate, drilled, deburred and ready to install in the firewall.

 

Riveting and goo-pucky complete.  The goo is the 3M Fire Barrier sealant, which I have previously used in other places on the firewall.  As I finish sealing the firewall, I will probably also use some of the ProSeal, as recommended by Vans.

Cleaned up and ready to go.

The next Rotax feature to amend was this fuel line (don't remember if it was a supply or return) hole in the firewall shelf.  New patch cut, drilled, deburred and ready to install with the Fire Barrier sealant.

All done, awaiting clean up.