Updrilled the upper engine mounts to their final AN-3/AN-4 sized bolt fittings. The upper engine mount sits just on the cockpit side of the firewall and performs three major functions:
1. Attaches the upper forward longeron to the firewall. 2. Serves as the primary support for the upper engine mount attach points. 3. Is the hinge point for the forward-opening canopy.
The mount is made of welded plate steel and is quite sturdy. Once I have all 4 mounts (2 upper, 2 lower) updrilled and fit into place, I'll remove them for painting before final installation.
Left side upper engine mount: 4 bolts into the upper longeron. Firewall just to the left.
Firewall side with AN-4 bolt installed. Silver cleco marks where engine mount will attach.