January 4, 2017 – Today I drilled two of the six holes in the firewall for the engine mount.
First things first, I had to rivet a stand-off on the bracket for the rudder pedals that secures the brake lines from one side to the other. This is my preference over running the brake lines through the bracket like normal. That option does not seem maintainable without breaking the brake system open.
I believe everything that needs to be placed on the firewall before the engine mount is done. I have to install the firewall recess, but I could get these holes drilled and cleaned up before I do that.
I struggled on a cold day with how to secure the mount to the firewall by myself. On that same cold day I gave up. Yesterday it was a little warmer, so I attacked it again. I used vinyl tape and clamped a 2×4 to hold the mount more or less in place. Seemed to work reasonably well.
I actually got the four corner pilot holes centered with this setup, so I started on the upper right hole.
You can just make out the pilot hole through the mount:
I started with a drill bushing in the mount, and drilled the pilot hole all the way through with a long #11. You can see that the dimensions for the bushing are perfect: .373″ OD and .191″ ID.
Here’s the #11 hole with a light behind it:
I then used core drills and BoeLube to step up to the final: .191″-248″, then .250″ -.312″ and then finished with .325″ – .375″.
Got the top two holes drilled, and the bolts slid right in:
Time: 1:05
