Rear Suspension Aligned

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.

Suspension Setup - Feeling Dumb

Today's goal was to set up at least the rear suspension. Before taking the wheels out I checked the camber and it was -0,8 and -1,3 on the driver's and passenger's sides, respectively. Used a nifty app on my Android to measure it against the wheel. After jacking up the car and taking the wheels out, the camber was different (and positive) since the suspension did the full drop. I made the calculations and (I hope that I managed to) set up the correct amount on the passenger's side to have -0,8º each side.

Then did lots of measurements to try to calculate the toe-in. Currently the rear has massive toe-in and the driver's side more than the passenger's side. But I couldn't make it with just the pen, paper and phone calculator that doesn't even do square roots. After much cursing and thinking, ended up storing the wheels away and left the car on axle stands on the rear, calling it a day. At home with a protractor and some scale drawings I'll manage it.

In between I recalled an old email from Steve from Aries where he advised me to have the washers on the base of the rear uprights all on one side (the front one, if I'm not mistaken). At the time I didn't pay much attention and placed them where it made easier to assemble the thing. Now I realize that it impacts castor and I'll eventually correct it when I get around to disassemble the uprights to fix the toe. That means I'll have to redo camber and after that re-check that toe is still correct. Sometimes cutting corners ends up giving a lot more work. And today I'm feeling pretty dumb with the math.

Tunnel Done!

Started another session with nail varnish on hand. Used it to mark the prop-shaft bolts so that later I can check if they are coming loose. I wonder if, when the prop is full of road grime, I'll be able to see the orange varnish I used... Hope so! It was fun that, after releasing the hand-brake and putting the car in neutral, I could push it back and forth (to rotate prop and reach all bolts) with just one arm, while kneeling next to the car.

Then, finished the work on the big panel of the driver's side tunnel. Last time I left it with the last rivnuts already in and just needed the dremmel to enlarge a couple of the holes to get the bolts in. Did so and also tightened the gear lever pivot again.

Then I released the throttle peddle, that is actually what holds the complete bulkhead to the chassis. Pushed it all together to the side so that I could fit the small panel and drill to fix it. Turns out that the panel needed an extra part cut out if it was to go in without taking the other panels out. Used the dremmel with a cutting disk to start the cut, then bended until snapped the part and used a big metal file to make it all clear. Held the part in place with a clamp, drilled, removed it, enlarge holes, fit rivnuts and the job was done. This is the end of the tunnel! (at least until I get around to make a vinyl cover for it.

It's odd, but I look at it and it looks bad, on the pictures it is actually OK. I'm probably comparing what mine looks with what I see of other in pics, so maybe it's not that bad... But I can't wait to get it all covered anyway.

Last bit was spent making a first attempt to measure the current toe-in of the rear wheels. It was enough to test what I have and may still need to perform a proper setup (material-wise). It also made me think that I need to get my trigonometry straight before I go work on it again.

More Work On The Tunnel

Another 2 and a half hours spent working on the car, all dedicated to the driver's tunnel panel. Only got the rivets for the bigger "half" of the panel in place. The small part that will require taking the throttle peddle out will have to wait for next week. Also filed and deburred an edge of the panel that was a bit too big near the rear. No pictures because it would look like the ones from last week. Not very motivating.

Drilling the holes and having to make effort in odd positions made very noticeable how out-of-shape I am. For a couple of holes had to stop twice to rest before the hole was drilled. Maybe I'm also needing to sharpen my drill bits.

Next week the plan is to use some paint to mark the prop bolts to guide me later when checking for bolts coming loose. Then it's the small panel. Further away... Finish tidying up the wires on the engine bay, align rear wheels toe (maybe fronts also, if they need) and tighten the wheels correctly. Then, outside panels.

Driver's Side Tunnel Panel

First, a note on the number of rivnuts to hold the panels in place. For what I read online (should have looked for this before) was that these panels aren't structural. As such, they don't need to be spaced at 10cm. Some people even just put a rivnut in each corner. So, the passenger's side will remain with one rivnut each 20cm and the driver's side will get the same treatment.

Started the session by finishing off the passenger's side. Enlarged a bit the panel hole for the gearshift pivot bolt to get in. Took some time fiddling with the gearshift to get the bolt in, but made it.

Then tried fitting the driver's side panel but wasn't able. I've been assembling parts of the car in an order that is not the usual one. This has allowed me to drive the car sooner. It has caused difficulties in several other occasions. This is one of them: the peddles and the panel shape make it impossible to go in. Since disassembling the peddles is out of the question, I had to look for an alternative. Cutting the panel under the dash allows me to get it separately and it will go almost unnoticed. Out with the cutting disk for the dremmel, drew a line and cut the panel in two.

The big part fits nicely and still got three rivnuts pressed in the chassis during this work session. The small part still does not fit. At least now I believe the panel can get fit by just removing the throttle peddle, which is not that bad. I'll have to remove it anyway to get the scuttle permanently fixed. Below a picture of the big part in place and the hole for the small part, another with the small part on the left and how the big one looks in place.

So, this side will still take another session to get finished. And probably will postpone the small bit for when I get around to the scuttle and/or side panels. So that I can tackle the rear wheels toe alignment first.

More Work On The Tunnel

Another morning spent on the car working on the panels. This time the objective was to get the passenger's side done. But before that, I modified one value on the Digidash settings. I had the "Pulses/Cycle" as 4 and it should be 2. I'm still a bit unsure on the remaining values, must see if I can get some confirmation and then I'll post them.

There was not much of a story with the panel work. Held it in place and drilled for two rivnuts. Removed the panel, enlarged the holes, placed the rivnuts, in goes the panel again, bolted down. This helps keeping the panel in place, a few more holes, take the panel out, enlarge, rivnut, panel in and bolt down, drill the remaining holes, take panel out, enlarge, rivnut, panel in and bolted down. To be perfect, only need to fix a bit the hole I opened to pass through the gear lever bolt, since it's a mm offset. Will do that next week, today was already late for lunch.

I had pre-drilled the panels with 10cm between centres. When putting the panel, it seems that 20cm centres is enough and so that is what is done. I can later on drill the remaining holes if I get told I should do it with 10cm.

Another Tunnel Panel

After some holidays, got three hours on the car. And was wonderful, seemed all I did went well and even quickly! I'm amazed.

Started by reading some data I configured initially on the Digidash (regarding ratios) and putting them down on paper. I'm going to ask if they are correct for this engine.

Then I grabbed the dremmel with a small deburring bit and enlarged slightly the holes that got misaligned on the panel I worked last. It was all done quickly (holding the dremmel as if it was a pen...) and the panel was finally set.

Placed some tape under the second panel for the tunnel top and located the part. Realized two of the holes I previously drilled were too much to the inside, missing the chassis rail... Anyway, marked the panel where it needed some adjustments and clamped it down. This time, used the 3mm drillbit through the ally holes to start the holes on the chassis rails. Then took the panel out, swapped to the 6mm drillbit and finished the holes. Some work with the rivnut tool and part of the panel was bolted to the chassis. Redid the two holes that were offset and also placed the rivnuts.

Last work with the deburring disk and the cutting disk on the dremmel to trim the panel where it was a bit too big. In the end, the panel was ready to fit.

Next is the passengers' side tunnel lateral panel. I'll need to buy more rivnuts... Also, looking to the "finished" work, I'm getting a lot more motivated to try to cut and stitch carpets and a leather-alike interior for the car, to cover the ally panels...