May 15, 2012
We built a jig for the suspension brackets. The purpose of the jig is to ensure the upper and lower wishbones rotate along parallel axes (or axises, not an actual word but at least it doesn't sound like a tool for chopping wood). The Locost frame is designed so the upper brackets can be welded in place, defining the upper rotational axis, and then the lower rear bracket can be moved back or forth on the F and G tubes until the lower rotational axis is parallel to the upper axis. Of course the way we described it doesn't make any sense , but the important thing to keep in mind is that the jig will make everything work.
Here's a tip for all you future Locost builders. If you want to use the Triumph "Metalastik" suspension bushings, don't bother painting your A-arms until after you press them in. Getting the bushings in is a major battle, and the paint will not survive. You can use all the dishwashing soap you want, but the C-clamp and small sockets and other devices you tried to use will come loose at some point and lash out at your freshly-painted A-arms. Trust me. Press the bushings, then run bolts through them with wide washers at either end to mask them off. Then paint.
The Locost book doesn't talk much about the bushing tubes. It gives you the basic dimensions, and that's about it. I think the tubes can be improved if you chamfer the inner edge on each end about 1/16". We did this on the second upper A-arm, and it not only made pressing the bushings significantly less painful, but it also kept the bushing from squeezing out of the ends too far, which means less interference when it's bolted into a bracket. I don't see any negative side effects to doing this, so I think we're going to chamfer all the tubes. Wish us luck.
For the past month or so, the Locost has undergone some pretty rapid and highly visible changes. You only have to go back over the last half dozen posts to see this, and of course it's been very encouraging. For the past week, however, things don't seem to be progressing nearly as fast. A tube here, a bracket there, lots of effort but no dramatic changes. That's how things were in the beginning, and I'm a little concerned that's how they'll be from now on.
On that disparaging note, and just to keep things from getting too boring, we clamped a few parts from the donor onto the new chassis. As usual, we're always surprised and amazed when stuff fits. We're also surprised and amazed by how huge those tiny MGB parts look on a Locost frame. Not that all MGB parts are tiny, case in point being the transmission mount. We hope to chop it down to size and strip it clean in the next day or two, so it'll look more like a Locost part, and not something from General Motors' truck division.
We'd like to weld the mount in place, but to do that we'd need to know exactly where it goes, and to do that we'd need to have the transmission, which would mean separating it from the engine. And while that seems like a reasonable and easy thing to do, the fact is the clutch worked fine when the car was running, and I don't think it's necessary now to go poking around in there. We'll take them apart soon enough, even though that means we'll have an extra part to keep track of. Although it's pretty unlikely we could lose a whole transmission. But not impossible.
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