In final preparation before hanging the engine mount, I had to think of the remaininng firewall forward plate work.
One of the things missing were the firewall passthrough holes for electrical wiring on both left and right side.
The left/passenger side hole will be used to pass the battery cable to the vpx and master switch etc. The right side will host engine monitoring cabling.
There are no location specifications on the plans but found the dimensions as shown in the picture from Bruce's website. 2 inch from the top angle and 2" 9/16 from the top rib. I did the same on both sides.
Drilling through stainless steel firewall is a pain. The firewall plate is mounded so no way to use a drill press. I figured the best way would be to have the back supported by a clamped big wood block.
Made the first cut on the pilot side with a regular twisted drill bit #40 and then enlarged.
Used a hole cutter to upsize to the larger diameter and deburred carefully. That stailess steel burr will cut through your finger like a knife goes through warm butter.
I then centered the safe air pass through kit parts in the hole and taped it with good old duct tape to drill the holes for the 4 screw that hold the part in place.
Deburred holes and all done.
Same precedure on the passenger side. Next image is just after being through with the hole cutter.
attach holes drilled (not deburred) and temporarily fitting the passthrough ring.
All looking neat and clean. This will finally be installed when my 3M firebarrier paste arrives so that I can finally screw this in place.
Forward look of the firewall so far with the two holes finished
