The doors of the GT40 have top extensions that essentially ‘open the roof’ to allow the driver to get in and out easily. Something required by its low height. However, the door tops require the door to swing fully open to let the driver in and out. That’s fine when you are in an open pit area. But in an enclosed trailer, or typical residential garage, not so much
The GT40 is also not known for its creature comforts. With the doors closed in sunlight or 80 degree or higher temperatures, the cabin becomes very close, almost claustrophobic. Coming from the Cobra community, I prefer the open vehicle. I tried to accomplish this with removable door tops. There are a few cars built this way. Some of the early Safir MK V’s had this as part of their build.
Unfortunately, there isn’t much documentation on the inner-webs on how to accomplish this. Let’s jump right into the deep end and cut the tops off.
As best I could determine, it appears the width of the roof above the window is about 1″. Some quick layouts indicated I could pack in the necessary hardware to make a threaded joint. I marked the top and attacked it with a cut-off tool. With the top split, I could test-fit the threaded side of the joint bracket into the door top.
The design of the joint incorporates these items:
- The joint is flat and straight from front to rear.
- The joint will have a 1/16″ rubber gasket affixed to one side.
- The attachment is done with two 3/8″-16 threaded screws. Threads on the door top side and a 5/8″ long bushing drilled just slightly over the 3/8″ on the door side.
- Two spherical bumps align the two pieces. They are about a 1/2″ radius and about 3/8″ tall.
The joint begins with two 3/8-16 nuts welded to the mounting bracket, approximately 12-1/2″ apart.
It is recessed about 1/8″ to allow fiberglass to cover it after it is glued to the top. I used MMA bonding adhesive to mount the bracket into the top. The side of the angle formed a flat straight surface for the joint.
With the door top rough-finished, you can then position the guide bracket on the door side of the joint. Remember to space the bracket back 1/8″ to allow for the fiberglass. I used the MMA adhesive very generously again. The steel not only provides a flat plane for the joint, but it also reinforces the joint considerably.
Working the joint from side to side, you are able to build a straight flat joint that will accept the 1/16″ thick gasket that will be glued in after paint.
