The assembly of the front corners was a little more straight forward but not without its foibles. The right corner didn't give me any problems but on the left side the bottom ball joint ferrule, the part that fits between ball joint and the spindle, was too tight a fit. With a micrometer I measured 0.6321", where as the lower ferrule measured 0.6293" Since 16mm = 0.6299" I guessed that the nominal size was that. I don't want to force these parts into place because they may gall and never seat properly so I had to fine hone the ferrule until it fit. I used 600 grit emery cloth and a leather thong to slowly work down the ferrule diameter, taking off almost 0.002". Patience won out and the fit was made.
The other problem I had was with the nylon bushings on the upper rear wishbone of both sides. For some reason, those shells were slightly smaller in diameter than all the other shells on the wishbones (this was, of course, after sanding out all the powder coat with my die grinder) so that when I pressed the bushings into place, the spacer tube was a press fit. I tried first opening up the bushing bore with a sanding roll on my die grinder but I felt like I was going to end up with a bell-mouth, which wouldn't be good. The spacers are 14mm so I used a 9/16" (14.29mm) drill to clean up the bushing bore.
The wishbones fit with fore-aft slop of about three washers. I figured, if needed, I could adjust the caster by changing the shim stacks. A good thing to keep in mind when it comes to alignment time. Speaking of which, there was one other off thing about the assembly. The tie rod ends are all RH thread. That means that you can't just rotate the steering rack extensions, like a turn-buckle. According to the Build Guide, "The toe in can be adjusted when the car is on the ground by rotating the rack whilst holding the track rods still." So I suppose that they intended to also say "after you disconnect the steering shaft"? I don't know about other builds but my steering rack has a welded-on bracket that would only allow intervals of one-turn with a very coarse thread. So in the short term I can detach the outer tie-rod ends from the spindle and rotate that end (intervals of half turn) but that's a real trial and error solution. It would be much preferred to have LH threaded tie rod ends and track rod extensions so that the adjustment is made turnbuckle-style, like every other car I have worked on. Sheesh.
I do want to say that the ATR components; the uprights, calipers, shocks, etc, are beautiful and I feel so much like I'm living the dream of my automotive life. I've wanted to have a vehicle built on race engineering principals for a very long time. I have a sketch I made in about 1978 while I was taking my first engineering class at Allan Hancock College. At the time I was driving a Triumph GT-6 and my sketch was inspired by that car and by books like Racing Car Design and Development, by Len Terry.
Len Terry was the designer Dan Gurney employed to design his single-seater cars, including his beautiful Eagle Weslake V-12 Formula 1 car. He also worked at Lotus and designed revisions for the Lotus 7 as well as their Formula 1 and Indy cars.
My next step on Thursday is to get the tires (tyres) installed and then put the chassis on its wheels on a set of wheel dollies that I've had for years. Then I can re-install the engine and make some final measurements for engine mounts. I can mock-up a set of extension blocks out of 4x4 wood and then take them, along with a dimensional sketch, to my local machine shop and have them make a set in aluminum.
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