Hi
Noticed that on MK1, 2 and now the 4 that there are two horizontal round bushes on the lower swing arm, however on the MK3 one of the bushes looks fixed in with some kind of vertical bolt and rubber bush. Is the MK3 three design different for a reason and is it inferior to the other standard design?
The ‘standard’ design is just that, not changed for maybe a century or more, dating back to when there was a metal fulcrum pin running through both pivot points, and with some designs the bearing surfaces were threaded (eg my old Humber Hawk) to maintain/adjust lateral location.
However the Mk3 one has the rubber always in compression under braking load and never in lateral shear. Think how the levers work. In the ‘standard’ version the forces can try to slide the wishbone back along the fulcrum axis, so putting the rubber into lateral shear stress as well as compression. The vertical bolt prevents any hint of slide, so minimising lateral shear. Twist shear because of the wheel’s vertical movement may well be about the same regardless of the bush orientation.
The Mk3 MX5 suspension is a great improvement on the old Mk2 Jaguar front suspensions I helped to rebuild all those years ago which seemed to have a very short life on the metalastic bushes.
See the nightmare of the Jag suspension here
http://valvechatter.us/?p=2121