How many planes are there?
I am not sure there is enough adult beverages or curse words to adequately fit the doors to an RCR GT40. And there are so-o-o-o many angles and planes to match.
UP – DOWN IN – OUT TILT IN – TILT OUT TILT FORE – TILT AFT TWIST.
And do all this while you hold a forty pound chunk of fiberglass and try to insert a pin thru the lower pivot when you can’t see or reach it. Words can’t describe it – you have to experience it to understand how tedious it is.
Oh, and I forgot to add in the deformed fiberglass components that have to be corrected midstream of the process. Enough said.
Lets' get started
I chose to modify the RCR hinges to use a heim joint as the pivot. This allows the hinge base itself to be hardmounted to the chassis. In and out and tilt adjustments can be done by adjusting the heim’s in and out.
I slotted the chassis to allow the base to be adjusted up/down and fore/aft. I made clamp plates to screw the mounting bolts into. I chose to use Gr. 8 mounting bolts as these get stressed pretty good as you tighten them down.
Hinge system
The kit uses two bolts, one top, one bottom. I chose to follow previous builders and convert this to one long bolt so the pivots are always on the same plane. It just makes for a better system. Yes, it is a little more difficult to assemble, but if you’ve ever installed door hinges before, you know how critical it is to have the hinge axis in line
RCR supplies a clamp system for the upper and lower pivot. The inner clamp plates were not tapped and to try to tighten this joint while holding a nut on the inside is asking the impossible. I tapped them 5/16-18 so the joint can be tightened from the outside.
I added a bronze flange bushing for the pivot joint. One less place to rust and create noise.
Anti-Intrusion beam
If you pour thru the posts on the GT40 forum, you’ll find a lot of discussion on adding reinforcement or anti-intrusion beams to the door. I’m not sure the beam is going to stop anything if you get broadsided, but it does add substantially to the door structure and really changes the way the door closes. Kind of like comparing closing the door on a Yugo as opposed to a BMW. You can tell a difference.
The beam is kind of tricky in there isn’t a lot of space to get one in. I used a 1 x 2 tube with a foot welded to the rear that bolts to the rear latch plates. The front is a tight fit into a socket with two bolts. The assembly sequence is important. You have to put the beam in first, then snake the front pivot in around it. The idea is to get the joint as close to the front pivot as possible. I am planning to make door boxes for the door so I cut out the center spacer from the RCR door. Makes it a little easier to get the beam in.
Thanks to Randy van Loo from the GT40s forum for this approach.
Mounting the door
I purchased my kit with the body panels ‘un-trimmed’. Too many stories about how they paid for factory-fitting and then had to do it all over again.
With the rocker panel installed, assemble the door & hinges to get it to fit into the opening. The lower edge, along the rocker panel will set the height of the door. Trim this in small increments so you won’t make the gap too large and have to rebuild the edge. Continue to work with this height adjustment till the corners that match the roof and the corners that match the front clip/spider joint and rear edge duct edges. Again, sneak up on it till you think it’s right.
Tweaking the fit
To mount and fit the door correctly, the bulb seal for the joint has to be in place. I used the 5/8″ seal recommended from the GT40 threads. It is designed to fit a 1/4″ lip. The depth of the lip has to be adjusted to position the bulb about 3/16″ from the spider edge. I marked this with a Sharpie all around the opening then cut the edge with a saber saw. Nice line all around the opening. To adust the thickness, I built an adapter to fit to my RotoZip. This allowed me to trace the opening and grind off the lower side to make the opening consistent. Once done, I sanded it to smooth it.
The bulb seal is a 5/8″ bulb. (McMaster-Carr #1120A431) You will need the full 10′ length to do one door. Install the seal then continue with your door fitting. You will find the seal adds some amount of drag when closing the door and also affects how the roof edges align.
Back to adjusting pieces. It takes some work but finally, you get there.
Finally, DONE! Oops, not so fast Cricket, you still have the other side to do.
