In a moment of craziness the decision was made to deal to an Australian assembled mini and raise the floor by 3 inches, or was that lower the roof ? The original minisprints built some years ago not only had the roof lowered but also a corresponding section was removed from the body. As this was the first attempt at a topchop, it was decided to leave the body alone and just lower the roof.
Firstly the pillars were marked with tape where the cuts were to be. The pillar joints were to be lapped which meant two cuts 3 inches apart. Then by unpicking the seams we were left with a nicely lapped joint, essential for strength. When the front and centre pillars were cut it was time for the cut to the rear pillar. This was cut off just above the swage line and again about 3 inches down from the roof. The roof was then lifted off and it was easy to clean up the flanges
ready for welding.
Normally with topchops it is necessary to cut the roof and insert a section because when you lower the roof and align the centre pillar, the front and rear pillars no longer line up.
In this case we laid the bottom half of the front pillars rearwards and the roof half of the front pillars slightly forward till they lined up. As can be seen from the photo as slight cut had to be made at the base and top of each pillar to allow this re-alignment. It was quite a straight forward process to align the front and centre pillars and clamp while a careful check was made prior to welding.
The rear pillar was slightly more involved. The pillar panel that was removed was moved forwards so the aperture for the rear quarter window lined up. That left a small gap at the lower edge of the rear window aperture and can be seen in the photo. That gap was filled with a small section made out of panel steel. Then it was a simple matter of massaging the rear panel and welding.
At the same time that all the roof chopping was carried out it was decided to deseam the car as well. This is relatively easy and is carried out best by removing a small portion of seam at a time and welding. I deseamed about 2 inches at one time.
It is advisable to back the new seam with a reinforcing strip just behind the deseamed portion. It dose help to contribute to the vehicles strength once the seam has been removed. We chose to deseam the roof as well for that "all over" smooth look.
As can be seen from the photo it is possible to achieve quite a neat deseaming job with the minimum of filler required. Of course once the roof is down it is necessary to remove a similar 3 inches out of the door window frames which is not too difficult. We also fitted a new rear valance and new outer sills and tidied up any minor rust in the process. The front had its bumper mounting flange removed which neatened the frontal appearance. The other relatively major item was the glass.
There are two schools of thought regarding the windscreen. It is possible to lay the standard windscreen back and cut into the roof to form a new opening for the screen. We went to plan B and bought a new laminated screen and had it cut down to suit
the modified opening. This car has retained glass in the doors and rear quarter windows. The only polycarbonate used was for the rear window. Being an Australian car it has wind down windows in the doors. There was a little bit of fettling of the front screen aperture to get the screen to fit perfectly and we had to disturb the paintwork.
March 2001