Sams Shed

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Shortening the Diff

I have a Ford 8.8 inch diff from a EF/EB Ford Falcon with a Limited Slip Differential. I want to shorten it down to suit the 323. Due to the RX7 LCA in the front, the front tyres(205X50X15) now protrude from the front guards by 65mm. Making the overall front track width 1,675mm. With 225X50X15 tyres on the rear and the standard diff the rear is 1,610mm. Meaning that the rear track width is 32.5mm narrower on each side. To widen the rear when I shorten it, I'll make the rear axle 65mm wider than the standard rear axle. The standard 323 Diff width is 1,338mm and the Ford 8.8 is 1,547mm for a total difference of 209mm. So the Diff needs to be shortened by 209mm - 65 = 144mm or 72mm per side.

The Journey continues

"It was the best of times, it was the worst of times" C.Dickens Long time no blog post, I guess most of the time I post on Instagram and neglect to come on here. In some ways it has been a good time for the shed and in other ways not so much. After moving house and getting a bigger shed I have more space, I've managed to purchase a Mill and a band saw as well as some other tooling. I've spend a fair bit of time mucking around with the front suspension and I think I have it how I want it now. Unfortunately with four children, the property, kids sport etc there is not a lot of time to spend in the shed, mostly later in the evening once everyone is in bed. I made a bit purchase and brought an RX7 FC, S5 13B motor in unknown condition with a MicroTech LT-9c for $3,000. I've started stripping it down and will clean it up and rebuild it, with the view of running it on E85. I've reworked the design of the steering rack location to have it correctly in f...

Issues

After mocking up the front suspension with some 15X65X205 wheels that I had lying around a few problems quickly became apparent. 1.) The tyre now sits approximately 45mm further forwards than it previously did and fouls on the edge of the front fender. Mock-up suspension location, at approximate full droop. As I was going to make fiberglass guards anyway to accommodate a slightly more aggressive flare this should not be a major issue. I'm quite happy with the actual stick-up of the wheel from the guard this is minimal and much better than I had expected, this will make doing the rear end easier also as I didn't want to have to cut it up extensively to accommodate a much wider track width. 2.) In trying to re-use the original shock and modifying the strut body to suit I've run into an issue as the shock is now so long that it hits the LCA meaning I would need to move the spring mounts down in-order to reduce the shock length. This may cause some issues if there is...

Spring Rates

I've spent a bit of time mucking around with a springs and shocks to try and make something from parts I have on hand to suit the new suspension setup. Basically I want to determine if I should use a set of coil-over bits and pieces I had lying around or cut and re-shape the std springs. After dong the maths on it(below) the aftermarket coil-over springs I had lying about are most likely going to be too stiff, being 28% stiffer than the stock springs. If I cut one coil from the std springs it will be 50mm lower and 20% stiffer which might be a good compromise. If I want to lower the vehicle further without having to buy new springs I could always lower the, lower mount. The numbers: Part Dimension Value Unit STD Strut Length 635 mm STD Strut Travel 190 mm STD Spring Length 345 mm STD Spring O.D 120 mm STD Spring Coils 5 STD Spring Wire Dia 10.3 mm ...

Parts Shaker

I've build a parts shaker to knock the edges and burrs off the laser cut parts. I used an old thermo fan from the Mazda and cut 3 of the blades of to unbalance it. I screwed this to a piece of wood with 20ltr bucket on it that hangs from the roof. I'm running the thermo fan from an old ATX power supply that I had lying around. I experimented with both wet and dry sandblasting grit as a medium, the wet medium seemed to work quicker but also the part start to rust. I left the parts in the shaker for about 4-5hrs by which time the edges where smoothed off and some of the surface treatment had lifted. I then coated the parts in Phosphoric Acid (Rust Remover) and coated them in Pentrol pending welding together once dry. If funds allow I'd like to purchase a powered coating gun and powder coat the sub-frame as I have an old oven in the shed I can use to cook it off.

Finished design of front suspension Rx7 FC to 323 sub-frame

So I threw out the original design as I didn't like a few aspects of it, mainly being that it was overly complicated, not as flexible with the position of the steering rack to the Lower Control Arms(LCA) and not as strong. To address some of these design flaws i re-designed it around some 25X50X2.5 rectangular stock I had in the shed. I also changed the design of the brackets for the power steering rack to make them easier to position providing more flexibility during construction. I've made the height of both the the LCA's and the steering rack adjustable by 60mm in three 20mm increments. The I've sent the parts of to the laser cutters to be cut in 3mm mild steel with all the files available here . Once they are back I'll mig weld them together as I don't posses a TIG welder at this time. New Sub-Frame Design Old Sub-Frame Design I built the old design in cardboard after printing it on paper sticking it to the cardboard and cutting it out. This...