Works rally rear bumperettes

Works rally cars were as light as the BMC Competition Department could make them within the prevailing rally regulations.  To that end, when the rules allowed, the works cars ran without a full rear bumper and, instead, used the bumperettes that were out of the parts bin of their smaller brother the AH Sprite.  These small uprights provide a bit of protection and weigh consideralby less than an entire big Healey bumper.  I wanted these on my car. 

Cape International (link to Cape Int'l) sells a kit with new bumperettes and the required mounting brackets.  They call them the "rally car overrider kit."  I ordered this kit.  Unfortunately, the mounting brackets didn't fit my 3000 MKII BJ7.  Steve Norton, of Cape International, is always great to work with and has helped me on a number of issues, so I sent him an email to discuss the misfit.  Steve said that they have seen this on rare occassions, but since they fit most cars he honestly hadn't addressed the random fit issue.  Fair enough....it wouldn't be the first time there was some unexplained difference from car to car.  I set out to modify the brackets I got from Cape.  

Since I needed to modify the mounting irons to get them to exit the rear shroud in the correct location, I decided to further modify them to tuck the bumperettes in closer to the body work and alter the angle to get the bumperettes to more closely follow the body curve.  The only critical tolerance issue in making these changes is ensuring that the trunk lid (boot lid in U.K. speak) doesn't hit the bumperettes when it's being opened.  To begin the project I marked and cut the mounting bracket arm into two pieces.  I put a second slice in the irons near the bumperette mounting surface to allow adjusting the angle of the bumperettes....on this one I did not cut all the way through, I left a small piece connected at the top of the iron to allow me to bend it while it was still attached to the main piece. (Pic #1, 2)  

   

Then I bolted the mounting piece onto the frame bumper mounting tabs.  A piece of strap metal had been tack welded to it to help facilitate proper placement of the second piece.  With the bumperettes loosely bolted to their mounting pads, I positioned the second piece to have it exit in the center of the shroud bumper bracket hole.  I moved the bumperette until it was about 1" from the body at its closest point.  I clamped the two pieces of the bracket together.  Fortunately, the required placement resulted in one piece exactly on top of the other, so it made for a very neat connection point. (Pic #3)  Then I bent the bumperette mounting plate until the curvature of the bumperette closely matched the the curvature of the body. (Pic #4)  Of course, I played with this a bit until I was satisfied with the look and clearance of the opening trunk lid.  In these pictures the bumperettes are covered with masking tape to keep me from scratching the new chrome during the fabrication phase.   

    

 

Then I removed the bracket and tack welded everything in place and refit it.  After validating the fit, I put both modified brackets in my vise to ensure I had both brackets identical. (Pic #5)  In truth, there is a fractional difference in the irons on the side to side angles to match the body curve, so I stamped them left and right as appropriate.  I followed that with final welding and grinding. (Pic #6,7)

 

Then I had them powder coated...on this one you can see the "R" stamped on the mounting surface to designate the right side.  (Pic #8)

Remounted on the car, the revised works bumperettes look great and clear the opening trunk lid. (Pic #9,10) 

So there you have it.  A fairly trivial bit of modification to the provided mounting brackets has provided a very tidy installation of the rear rally bumperettes (or overriders if you prefer). 

Steve Thomton

This project paper was first posted on January 3, 2010