build diary

April 29, 2004:
Whoops.
I looks like I might have a problem. My steering is now set up with the rod ends above the steering knuckle. But when I set up the location of my steering rack, I believe I measured as if the stock ball joint was being used, and that hangs below the knuckle. The tie rods are visibly at the wrong angle and I suspect the current setup has massive amounts of bump steer. I'll have to do some measuring to determine is this is the case or not. Simply moving the rod end so that it's below the knuckle causes problems due to the extreme angle of the attachment - at least when the suspension is at full droop. Both the rod end angle and clearance of the knuckle are a problem here. I'll have to do some thinking about how best to resolve this. Going back to Miata ball joints and more normal rod ends would certainly work, but then I'd need new steering knuckles because the tapered hole has been drilled out. Raising the steering rack will also cause problems with the angle of the rod end. Sigh. I'll find a way to make this work. Hopefully without having to spend too much time machining the knuckle. I can see now that it would have been simple to just keep the factory ball joints and extend the tie rods. Not that I had any straight tie rods to extend! I'll try to get some photos soon of the problem.

I started test-fitting a few of the body panels last night. There are some extra bends needed (no big deal) and one of the panels needs a little tweaking to clear the neutral switch on the transmission. The switch protrudes just a little bit too far to be covered by a flat panel. They fit reasonably well, but not as well as I'd expect from a CNC plasma cutter - the patterns need some work. This has been true of every aluminum panel I've tried so far. Basically the angles aren't quite right or holes are offset. Nothing that's going to leave a visual mis-match so it's only an irritation when I'm assembling. While I certainly saved a lot of effort by buying the panels pre-cut, I probably would have obtained a better fit by cutting them myself.

Update: after a bit of perusal of the FK Bearing catalog, I found a high-misalignment version of the bearing I'm using. It'll give me an extra 7 degrees of rotation as well as being slightly longer - both of which are good. It's also going to clear the knuckle better due to a lip on the ball - and to top it all off, it's rated for 5,000 lbs greater axial load. The downside is that they're about $20 each, almost three times the price of my earlier choice. Part number HJMX7T if anyone's interested.
entry 255

April 30, 2004:
One last view of the PPF modification by Lester Seal.
The passenger compartment is not as compromised as it appeared in photo 196. He reports that he will be using 1/8" steel plate on the passenger's side upright to replace the 3/4" tube that he's removed.
entry 256
An example of the fit of the aluminum body parts.
Lester informs me that his are the same way. Once the transmission cover has arrived, I'll make sure it's bent well enough to cover this up nicely.
entry 257
A blurry photo of my bad steering geometry with the rod end on top of the knuckle.
entry 258
The corrected steering geometry.
entry 259
The original rod end didn't deal well with this sort of angle.
I'll do a little grinding on the knuckle as to clear the threads. This is at full droop so it's a worst-case scenario.
entry 260
The fuel return line.
Okay, it's not the prettiest. I'll have to see what I can do about this. Maybe a couple of feet of braided stainless line just for this section...
entry 261

May 3, 2004:
Busy weekend!
I spent some time finishing the wiring in the rear of the car and working on routing. It's all looking nice and tidy although I still have to work out the connectors for the taillights. This will be easier to do when the tails are mounted - I learned the hard way on my Land Rover rewire that just adding in extra wire "because I might need it" makes for a very messy harness.

I've also started on the instruments. I'm not completely happy with how they look right now, but there's always the chance to change them later. I really don't want the car to look as if I simply stuck a factory gauge panel into the dash, so I'm taking pains to hide the "Miataness" of the donor panel. It meant a lot of grinding and careful shaping to get as far as I did. If I paint the dash black it'll look more integrated but I was rather hoping to stick with body colour. We'll see.

Typically the way you build a car like this is to install the engine and transmission very early on. Because I'm still waiting for my engine, I'm having to work in a bit of an unusual order. The logic of when to install what body panel is a little complex, but the good thing is that I'm working with a mind towards how the engine will be installed and removed easily.
entry 262

The wiring at the rear is coming together.
I'd rather not have the axle chew into this, so I'm being careful to keep it all well tied down.
entry 263
Not a bad measurement - the steering column hole has been drilled in the scuttle.
entry 264
Working out the placement of the instruments.
They're not centered on the dash because the tach would be covered by the wheel and the offset transmission tunnel would look a little strange.
entry 265
I'm taking care of Turbodog for the week.
He seemed to think that I had better things to do than cutting holes in fibreglass.
entry 266
Holes are cut for the instruments.
I had to enlarge the holes freehand and I screwed up on the speedometer. Nuts. I'll try to patch that up with some bondo.
entry 267
The modified instrument cluster.
I even wound the odometer back to 0.
entry 268
This is interesting.
The Japanese "Miata" (the Eunos Roadster) comes with a 180 kmh speed limiter. It can easily be disabled by removing a screw. Looks like the US instrument cluster is the same part. What do you think would happen if I put a screw in there on a stock car?
entry 269
A closeup of the instruments.
I was thinking about mounting the chrome ring to the dash itself - that might have looked better, but it would have been difficult to add glass later. The mounting bolt is just a temporary one as I will find something that looks a little better.
entry 270
Hmm, it's starting to look like something.
entry 271

May 4, 2004:
Nothing exciting, just a little more time spent reworking the holes for the gauges.
They've got a beveled edge now so the gauges look like they belong. I need is some plastic to cover them and I'll move on.

CMC did another 2-day build at the Walter Mitty vintage event and even managed to drive the car on the autox course as well as partway home. Impressive. A conversation with CMC did reveal some new information, though. If the front of the diff is not hard mounted to the frame, it'll cause problems with a loss of drive as the diff moves around. I can't think of how this works and Steve didn't really seem to know either. The only theory that I and my coworkers have come up with is that the driveshaft is pulling free of the splines in the transmission but that doesn't seem plausible. A diff will work at any angle. He described a clicking when trying to go uphill. Strange....The existing mounting technique works for a while but eventually loosens. I may try using a locking nut on that long bolt on the diff if I can't easily work out a mount on the frame itself - after all, if it works when it's first put together, it should continue to work. But the new frames are being shipped with a hard mount for the nose of the diff instead of the rubber one I have now. Time for some mulling-over in the garage.

In further news, the remaining bits and pieces of my setup should be shipping tomorrow. I'm moving towards the point where I can paint the body panels - that will be exciting!
entry 272

After a bit of reworking of the holes, the instruments look more integrated.
It's hard to photograph this!
entry 273

May 5, 2004:
I've polled the Grassroots Motorsports forum about the differential mounting.
One good suggestion was to build a PPF out of tube - or at least a skeletal version of one. This isn't going to work without changing the shape of the transmission tunnel, however. The real question is whether it makes any significant difference to have the diff mounted to the frame - and thus put the torque loads through it - or have a PPF substitute. The former is obviously easier. Steve has informed me that he'll be sending the new bracket to me to weld into place. I guess it's time to wire the garage for 220v!

There is 4" of splined shaft at the end of the driveshaft so I doubt the CMC-built cars are pulling the shaft free. Puzzling.
entry 274

For those who are helping me work out the various questions about bracing the diff - here is the rear mount for the transmission.
The vertical tube on the transmission tunnel is directly behind it.
entry 275
The current diff mounting.
entry 276
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