I have been told it is easier to install the oil cooler box assembly on the engine side of the firewall before installing the engine mounts. I purchased VA 186, constructed it and flush riveted it to the firewall. In addition, in order to attach the side skins to the fuselage, I needed to modify the empennage bucking bar used to buck rivets on the elevators. It was necessary to provide a taper taking 1/4 inch off and tapered back up the bar 2 inches. A machine shop needed $120 to do this. I purchased some 36Grit sandpaper and with my belt sander and $10 I accomplished what I needed.
Oil cooler box assembly on engine side of firewall
