Today I worked on the carb heat door. I used some posterboard to make a template for the shape of the door so it would match perfectly to the profile of the FAB intake neck. I then used the tempate to fabricate a door and to also make the cutout in the top plate. The hole in the top plate is approximately 1/8" smaller all around than the door itself. The installation of the hinge and spacer was a little tricky. One side of the hinge is inverted as it mates up with the other side of the hinge. This along with the spacer is needed to make sure the door seats properly against the top plate when carb heat is not applied. Once I had everything aligned according to the plans I drilled the hinges/spacer to the carb heat door and the top plate.
With this particular design, the carb heat air will still be filtered.
Carb heat door cutout from top plate
Carb heat door drilled to hinge, spacer, and top plate - front view
Carb heat door drilled to hinge, spacer, and top plate - top view
