suspension-wishbone-jig-001It has taken nearly 6 months of evenings and weekends to design and set-up the drawings for the suspension components for the Porshe 917...and finally those designs are starting to become a reality.

ARRK started manufacture of the suspension wishbone jig at the beginning of December. We had one or two minor issues, but so far the jig and wishbones are building exactly as CAD.

Having had a chat with Anthony (the ARRK technician and fabricator) we decided to tack together a full set of LHS & RHS fronts and both the LHS & RHS original short rears for 17" track rims & tyres and the extended longs for the 14" road rims and tyres.

The completed set of tacked wishbones coincided with the delivery of the first set of NC uprights which arrived early January, and then we completed a pre-assembly to check that everything fitted the chassis, and is dimensionally correct to CAD. After the final welding of the wishbones, the machined rims, stub axles, brakes, and GKN competition half shafts all arrived between mid to late January.

Click here to visit the Suspension Wishbone Jig and Manufacture page.

The BBS 90mm centre spinner nuts arrived last week. BBS are going to supply the thread details, so I can insure we machine the correct thread on the stub axles. We will run a test sample thread on a sacrificial tube to ensure the nuts fit correctly, before machining the thread onto the stubs.

Click here to visit the Wheel Nuts page and view images


We now have our first set of casting for the 1-Piece magnesium centre spinner wheels. Creasey's cast and then heat-treated last a couple of weeks ago. Click here to see photos. They look excellent!

I was particularly worried about the blend of the spokes into the rim, but this looks exactly as per my CAD models. So have to extend my thanks to Allwick's the pattern maker and particularly John the owner for the detailed feedback he gave during the design phase.

The next stage is machining of these casting to give the first road set of rims, an 8.5" front and 14" rear. This should take place in November, and once they are ready I will post a detailed set of images. And about time to order a set of road tyres.

140914-Final-suspension-jigWell summer has come and almost gone now, and not much progress on the first car build as we would have liked due to the reasons listed below. And also have to apologise as no updates to the website since April.

The slow progress on the build has been due to a combination of things. First I had to spend much time finalising the rim designs to enable the patterns to be manufactured. Second designing the suspension has taken me most of the summer. And third, my partner has not been very well through the summer, so that has slowed the engine re-build and the general progress of the first car build. Oh yes, and forth I have changed contracts, and now down at McLaren. So this has eaten into my spare time to progress the designs.



We had many questions asked what our intentions are with the project. The initial intent was to build 2 917 replicas, mine to be for road and track, and John’s other for track only. But as I started to develop the chassis, it soon became clear that to build 2 repeatable chassis, would require a complex jig. So in parallel to developing the chassis, I started to design the chassis jig. And then to get similar repeatability for the suspension mounting brackets, I designed front and rear suspension jigs.

Then as we started to build the first chassis, it became clear that the jig was working very well, and that we could build repeat chassis to within a tolerance of 3 to 4mm for the main chassis, and 1 to 2mm for the suspension mounting brackets. And with everything designed in Catia, it also possible to offer a bespoke service to customers, to package seat, pedal, wheel, and gear change position to suit individual driver ergonomics.

And we can offer the same bespoke service to provide complete CAD design to package whatever engine and gearbox customers might want. Including water cooled Porsche engines, and in fact any water cooled engine. As the engine bay is designed to original dimensions and in fact we can fit an original flat 12 engine and box. We had one chap who was seriously interested in fitting big block V8, and I’m confident this could be done as well. Would need to investigate side mounted rads, and carry out fluid dynamics, to insure they would work efficiently.


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Tel: John Hartland 07711 807 928


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