With the shims added, there's still not a whole lot of clearance, but there is a little, which is all that's necessary. |
And there they are - very nice. |
Earlier in the build,
I'd discovered a problem with the way the chassis had been welded - the trailing arms wouldn't fit in the brackets
they were intended to go into, with the result I had to chop them off, fabricate some new ones, and weld them into
place. I'd thought that this was the only problem with the chassis - not so. Having fitted the rear axle, I fitted the Panhard rod which locates the axle laterally. The Panhard rod is adjustable, so can be used to ensure that the rear axle is central relative to the chassis. I initially set the Panhard rod up so that the gaps between the trailing arms and the 10mm steel plates on the outside of the chassis were equal on both sides. In the process, I noticed that it was necessary to adjust the Panhard rod to a much longer length than had been necessary on the Furybird. Once it was in place, I checked the location of the rear axle by reference to other parts of the chassis, and immediately something seemed wrong. For instance, the leading arms at the top of the chassis were at different angle. |
At first I assumed it was my modified trailing arms that were the problem.
But they weren't - they were well within the tolerances that the rest of the chassis appears to have been built
to (i.e. +/-3mm...). Then I thought the axle might have been bent in the crash. It might have been, but not enough
to explain the offset. Then I wondered if the suspension mounts welded onto the axle might be bent. They were,
but again, not enough to result in the axle being an inch out of line. Eventually, after a lot of measuring and
pondering, the root cause of the problem became pretty clear. The problem is that the whole of the bottom rear part of the passenger/driver compartment has been welded on at an angle. Basically, a substantial part of the chassis is wonky. Because this part of the chassis runs very close to the trailing arms, the angle of this part of the chassis (and the 10mm steel plate sections in particular) define where the rear axle sits relative to the rest of the car. And because the chassis is wonky, the rear axle isn't central. This is, of course, once again A Bad Thing. The rear wheels are supposed to be behind the front wheels, not wandering off to one side. I ended up taking quite a few pictures and measurements to satisfy myself that the chassis was indeed lopsided. Rather than bore everyone with all the minutiae here, true lovers of bent chassis pictures can take a look here. In order to allow the rear axle to run centrally relative to the chassis, it was inevitable that the 10mm plate on the driver's side had to go. The trouble is that it's a fairly integral part of the structure, not to mention that the lap and crotch straps mounts for the driver's safety harness are welded to it. So it had to go, but it also had to be replaced. |
And for good measure a picture of the same thing from the outside of the chassis. |
I then welded a length of 2" x 1" tube between the stump of 10mm plate left on the chassis and the rear upright chassis member. The hole in the middle is a 7/16" threaded boss from Rally Design with a 3mm steel spreader plate welded around it. The heat of the welding actually made the 2" x 1" tube bend slightly, but in fact this meant it fitted rather better than it would have done if it was straight... |
With the rear of the chassis now bodged into something approaching symmetry,
I thought I'd try and finish off the steering. Having already made the adaptor pins to go in the uprights the next thing to do was made the track rod adaptors that would link the track
rods (M14 x 2.0 coarse thread) with the male rod ends (3/8" UNF). And here they are. Very nice, though I say it myself. Actually, the one on the left is the Raceleda one, and the one on the right is the one I made. The carbon sheet they're resting on is a bit of pre-preg I made a while back - I'm rather pleased with that too... ;) |
I'm currently hoping that this will be the last chassis rectification work that's necessary and that I can now get on and build the damn thing. Mind you, I thought that when I found the first evidence of Mr. Monkey's workmanship. We shall see... |