After spending some more time measuring the rear of the car and knowing what trigonometry I needed to use, I got to the conclusion the road I was travelling was a dead end. Why a dead end?
(WARNING: Long confusing wall of text that causes headaches! Skip paragraph if you don't have pills or alcohool near by).
Based on this site (http://www.hillmanimages.com/912/adj_toein.html) and the wikipedia page on trigonometry (http://en.wikipedia.org/wiki/Tangent_function#tangent) I (kind of) understood what I had to do. So, consider a parallel line to the centre of the car going from the rear side of the lower wishbone to the front side. Then, considering the pivot rod that passes under the hub, measure the distance from the front centre of it to the line and from the rear centre to the line. Measure the rod. Subtract the distance from the front to the parallel line to the distance from the rear to the parallel line and you have a triangle where 1) the hypotenuse is the length of the rod, 2) the adjacent is the distance from the centre of the rear of the rod to the parallel subtracted of the distance from the front centre to the parallel line and 3) the opposite is the distance on the parallel line between the front and rear intersection points. Confused? I was for a long time!
With all those measures and a scientific calculator app installed on my phone, I could calculate the tangent and cotangent. This is the bit that still didn't make much sense to me, it should be the tangent I was looking for but in the end the cotangent was the right thing.
Anyway, the calculator and the formulae gave me values in minutes, just had to convert to degrees and all was great. Not. Got to the conclusion that, on such short values, a millimetre made a lot of difference. And I was measuring in a way that measurements were not that precise at the millimetre level. I had to give up.
(IT IS SAFE AGAIN)
So, I would either buy poles and fishing string and try to do it all in a bigger scale or resort to another approach: Since this is a chassis made on a jig, it is similar to all others done on the same jig. So, proper adjustments made on one should be the same mine required, within acceptable tolerances. I reached to fellow builder Iain, that has his car on the road now and went to a proper alignment shop. He has several times been very helpful (thank you!) and this time again he came to my rescue. I asked him how many threads were visible on the bolts from the adjustments and he provided me that information.
So, today I went to the car with renewed confidence. Since I was going to separate the hubs from the lower wishbones to adjust the toe, I might as well also properly adjust castor. When I first assembled it, Steve told me to cut a bit of an extra iron tub (from suspension crush tubes) to pack the space between the hub and the front of the wishbone. I cut corners and packed with washers. And since it was being hard to make it all fit, I packed washers part on the front, part on the rear... Only later I realized this was 1) bad to the castor settings and 2) on one of the wheels made the rod be so near the inside of the wheel that it ripped off the calibration weights I had there.
So, the rest is history. Released the left hub, adjusted the toe rose joint to expose 4 threads. Then spent some time with grease, an iron bar and the rubber mallet fighting the rod and washers to get the thing assembled with all the washers to the front. The top bolt that adjusts camber had 5 threads exposed, just like he told me it should have, so I did not touch there. Fit the wheel and, happily, no rubbing of the rod on the calibration weights!
Then it was doing all again on the right wheel, considering 2 threads on the lower rose-joint. Iain said 3 threads at the top, I had 4 exposed from when I measured it all with the level app on the phone. Opted not to touch that, but I have a mental note to recheck it after rolling the car a bit.
Last thing I did was to unpack the ally side panels and offer one to the car. I think I'll have a bit of a trouble fitting the rivets on the lower side of the car, probably will have to tilt it a bit. But with the side panel on, it looked a lot more... Finished!
I still have to make my mind if I want to cut the driver's side panel in half and hang the front part with rivnuts to allow "easy" access to peddles, brake fluid reservoirs and engine oil filter or if I rivet it all and hope for the best.
