After a delay of almost 1 1/2 years on the 4E-FTE Mini project due to a significant back injury, recovery, long wait for surgery, and more recovery/rehab I've been able to restart work on the Mini project starting with some low-level physical movement.
The standard Mini bonnet hinges only allow the bonnet to open to a limited angle and a single-piece hinge with an altered hinge shape barely improves this opening angle (as I've tried in the past), and while I love the idea of the articulated hinges that used to be sold by Minivation UK, they have not been available for many years so I decided to try it myself. Without a 3D scanner I had to manually confirm the panel shapes and mount locations around the scuttle panel with manual mark-ups, sketches and 3D printed test pieces templates.
Using
motiongen.io (free online software tool used for designing and simulating linkage mechanisms) the linkage locations were eventually determined.
A few iterations of 3D printed prototypes finally confirmed a new articulated hinge design that provided the correct clearances and angles. The new hinge bracket was also designed to bolt to the factory bonnet hinge location under the scuttle panel.
Clearance near the wiper motor is tight
With the bonnet bolted to the prototypes, clearances and movement was then tested.
The challenge was then to find a reasonably priced company to get all the parts laser cut from 4mm steel (One price that I was quoted was over USD350!). After a lot of quoting I found a much cheaper supplier and had everything laser cut from 304 stainless steel.
After some minor surface clean up, I TIG welded (with stainless filler rod) all the main pieces together. The small holes are used to hold the three pieces of the main mount together with 4mm bolts while everything is welded together. Once the main piece was welded and bolted into the Mini, the bottom support tab was tacked and welded on :
With the steel hinges assembled and bonnet bolted on, the open/close movement was smooth however with the bonnet was closed/latched I found that there was still movement which meant bonnet height at the rear was inconsistent whilst closed. It looked to be caused by the small difference between bolt thread diameter and the holes in the linkages, and compounded by the multiple bolts/holes in the linkages.
Unfortunately after a few weeks of trying potential fixes (bushes, springs etc), I could limit that movement slightly but not eliminate it and meant that the rear of the bonnet had the potential to move up and down whilst driving, and randomly sitting too high or too low once closed.
So after a substantial amount of time over a few months, I have given up on this idea and will revert to using the factory hinges. At least it was worth a try...
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