1) Build Your Own Sports Car by Ron Champion
2) Competition Car Composites by Simon McBeath
3) Race and Rally Source Book by Alan Staniforth
4) Competition Car Suspension by Alan Staniforth
The two Alan Staniforth Books are an absolute God-send to beginners starting out in chassis design and suspension set-up.
At this stage, it was realised that the 914 front Macpherson struts could be modified in the usual manner by cutting off the top of the tube in the hub, welding in a threaded plug to take a rose (heim) joint which could then become part of the top wishbone.
So now we were into front and rear roll centres, effective swing axle lengths, wishbone angles, chassis mounting points, steering rack location to avoid bump steer etc etc.
Some of the design work around that time is shown below.
At the same time as thought was being put to the front suspension, I was wondering what to do about the rear and particularly what would be a suitable rear upright. This was solved on a visit to a The Classic Car Show at the NEC where Gardiner Douglas (gdcars.com) were exhibiting their Lola T70 replica.
Lo and behold the rear upright seemed to fit the bill. A subsequent visit to their factory in Long Bennington near Newark, Nottinghamshire revealed that the uprights took Ford Sierra/Scorpio hubs, discs, calipers etc. After the usual exchange of funds, I left with the pair of uprights shown below.
The next job was now to obtain the necessary Ford parts and through a combination of used parts, refurbished exchange calipers, new ventilated discs, and alloy wheels from a Scorpio Cosworth, the rear corners were built up. The bottom wishbone and top link could now be made up from CDS tubing together with the top and bottom radius rods. A pal in Edinburgh - Sandy Cormack had a lathe so I spent days on and off with him turning threaded insets for the wishbones/links and various spacers to suit different rod ends. Sandy is making a Porsche 906 replica utilising a Boxster as his donor car so we give each other mutual support as we progress our respective projects.
It became very clear at this point that the idea of using the 914 front corners adapted for double wishbones was not going to work since the 1960's design of discs and calipers looked like bicycle brakes compared to the ventilated discs and Collette fist type calipers on the rear. The only practical solution was to fit Ford Sierra/Scorpio front corners. This, of course, meant a complete redesign at the front since the pickup points on the Ford hubs were completely different from those on the 914 which resulted in different wishbones and pick up points on the chassis. The steering arm was in a different place which meant that the steering rack mounting had to be moved. Since the steering rack was now in a different place the steering column had to be relocated. The chassis then had to be modified to cater for the new position of column and so on and so on.
The uprights were modified by fitting a threaded plug into the top location where the Macpherson strut normally fitted to to the Ford Hub to convert to wishbones top and bottom.
As I said at the beginning of this tale, the objective was never to make a replica but to have a lookalike or fake!!
So, the decision to use Ford Sierra/Scorpio corners allowed me to acquire a selection of parts for the front which were again second hand, exchange or new. The fronts now had ventilated discs and large Collette calipers and the top and bottom wishbones could be made accordingly. These were fabricated by my pal - Peter Bentley who has a fully equipped machine shop in Monmouthshire. Peter was the chief of development at at Henley/Lansing Henley/Linde forklift trucks and nothing in metal is beyond him! When the wishbones at the front and rear had been sorted out the chassis could be finalised. All through this process, chassis design had been keeping pace (or not!) and a prototype chassis made by cutting tubes and tack welding them in place. I was lucky that there was a fabricator - Dick Noble - in the village who helped out to the extent that it would never have been built wihtout him.
Before the final chassis design was sorted, decisions on what pedals and their location had to be sorted out and mounting plates and studs incorporated. How was the engine and transmission to be mounted?, what mountings were to be used? - I finally used competition 911 units from Pelican Parts for both.
Where was the battery to go? Where was the fuel to go and what sort of tank was needed. The story of the tank is worth telling but it can wait for another day!
The overall design philosophy was to optimise the torsional strength in the cockpit area by incorporating deep side members and a tunnel tied in to the front and rear bulkheads. The sides and bottom of the chassis would be covered in 16swg aluminium sheet as would the top of the chassis above the pedals where the fuel tank would sit and up to the front bulhead except for an opening where a sump in the fuel tank would come down to just above the steering rack. The sump was to prevent fuel surge on cornering. I still realised at that point that I might be going quickly!
At last the chassis was taken to Dick's workshop for final MIG welding. The results are shown below.
