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Any more progress?

thanks for asking...my build hit a roadblock in late october, due to impending wedding. unbelievable how much work went into planning that. before that, i started on the rear lower wishbones. i've put in some more work since getting back from the honeymoon a couple weeks ago, and one rear lower wishbone is tacked together, and a second is being built. pictures and update will come hopefully by the weekend! it's awesome getting back in the garage. oh, and being married is ok too.

finally an update! the past 5 months or so have been hectic. as mentioned above, the project was delayed by wedding planning (married 1/2/10!), and since then, it's been honeymoon in hawaii (awesome), and working on the other project (the house). got some new furniture, painted the living room, some other small projects to make the house livable for a woman. it had turned into a bit of a bachelor pad since i moved in last april. and now onto the update!

shortly after getting back from the honeymoon, i finally got around to driving to my brother's place to borrow his utility trailer to haul of the remains of the donor miata. for some reason, wives don't seem to like miata bodies that have been stripped and sawed in half sitting under blue tarps in the driveway. strange. like my tow vehicle?



in regards to the car, last i left you (if anyone is reading this), the basic rear configuration was done. i've slowly been working on rear a-arms since october, and today i finally got a chance to work on the upper rears. they're obviously not totally done, since i need fully weld them, fab a shock mount on the lower rear, and clean up the uppers. as always, critiques are welcome. the way i did things (i.e. not the smartest), shock clearance is going to be very tight. i think i'm going to order some shocks and see where they fit. i'll probably be looking for some small body shocks so they take up less room. if that doesn't work, i'll have no choice but to consider this a learning experience and go back to the drawing board.



The bushings on the lower rear outboard points are energy suspension 9.9107's.

Two seats and a wheel bolted to the car. Almost there, eh?

I'm glad to see that you are working on your car again! And congratulations on getting married!

I have one concern. The upper A-arms are in a T-shape. I know you said that you aren't finished with them, but I hope you plan to triangulate them a bit more. A-arm's are called A-arms because they are shaped like an "A". When shaped like an "A", like you lower A-arms, they will be very strong. However, when in that T-shape, I think you will see some bad deflection, when there is force on it from any angle. I wish I had an FEA program on my computer to show you what I mean. So, paint will have to do for the moment (see below). If you need them to be shaped like that for clearance of other parts, maybe you could add a gusset at the T- intersection?


P.S. I do like your tow vehicle. There is no need to have a truck to tow a load like that

i appreciate the reply! yes, the reason for the shape is for clearance of other things, but i definitely was planning on triangulating them further. i just wanted to wait until i got shocks/springs before figuring out what will be possible. im hoping to add another bar, but i might have to settle for gussets, like you mentioned.

while waiting on some parts to finish up the rear suspension, i started working on the diff mounting. it's the first major component of the car bolted to the frame! the brackets are still only tacked in, but that's the general idea.

Wow, it's been quite awhile since my last update. I definitely have not been sitting idle, but life has a way of getting in the way of the truly important things, like building cars. I've been trying to spend at least 30 minutes a day 2 or 3 weekdays out of the week in the garage, with an hour or so on the weekends. Thus, progress has been slow.

However, I'm really close to hitting a big milestone...the chassis is almost a roller (with no steering...is that still a roller?). On to the pictures!






There's a whole lot of finishing work to be done, and everything is only tacked together, so if anyone sees anything horribly wrong, by all means point it out now. I'm not terribly happy with the rear suspension. I'll eventually build new arms for the rear, but this will be good enough to get me rolling. Hopefully it won't be another 6 months before another update, but rest assured I'll keep plugging away.

Your build is coming along nicely. Just looking at the rear coil springs, they seem to be made from large diameter wire. Do you know your wheel rate for the rear suspension?
Dave W

thanks! the springs are 180 lbs/in, and rough calculations put the wheel rate at around 117 lbs/in. I expect to do some experimentation with spring rates to find the right setup. With this project, I'm trying not to over analyze things by calculations. I'm just going to build the damn thing and spend some time tuning it after it's done.

i would be more inclined to do lots of analysis if there was such thing as the perfect wheel rate or wheel frequency, but so many of these things come down to what "feels" right to you. with springs of different rates being relatively cheap (i think they're $40), i can afford to mess around with it later.

You should be right in the ball park with those numbers. For some reason they just looked fairly big just eye balling them in your picture. Keep plugging away at that build.
Dave W

I am terrible at taking progress pictures. I just don't take the time to take pictures while I'm in the middle of something. I envy you guys with awesome build logs that detail every step.

I took the plunge and shortened the Miata rack to a width of 19.5". I followed Keith Tanner's book's and numerous members' instructions, and it came out good (i think). Built mounts for the rack:




Does anyone else think cross bars between the two tubes are necessary? I can't decide if they'd be extraneous, but I think I'm just going to add them for peace of mind. Before anyone asks, I did bolt through the tubes, but I welded in a 1/2" od round tube in the mounting points.

With all next week off, I am currently working on mounting the engine, combined with placing the steering column, and fabricating the tunnel. I ordered the material for the floors and a really cheap 300mm steering wheel from ebay that should be in next week. Will update then.

edit: man, the flash on the camera really makes all the surface rust on the tubes look terrible. It's a never ending battle...I'll just have to grind it all off when it comes time to painting the frame. With 70-85% humidity throughout the summers, there's really not a whole lot I can do about it.

Andrew,
Nice job so far. Keep up the good work.

The last pic makes the rack look in line or below the lower pick-ups. Are you planning on raising it a bit, or is supposed to be so low?

Your steering rack and the lower arms don't work in their current configuration.
You need to work out a solution to the problem that nearly every builder that used miata uprights tackled - the interference between the arms and the tie rods.

Moti

Thanks for the replies, guys. Actually, I thought (and read) really long and hard about the tie rod/a-arm interference issue. If you'll look at my front a-arms (scroll up a little), the lower balljoint is mounted on the top side of the arm instead of underneath like it is in the Miata. So at ride height (lower balljoint at the same height at the lower pickup), the arm isn't parallel to the ground; it's actually angled down. This allows for clearance between the tie rod and the lower a-arm.

I can't confirm this 100% yet, since I haven't gotten my tie rod extensions yet, but I zip tied a piece of wood to the tie rod end and the tie rod and went from full bump to full droop, and there's sufficient clearance between the two. I don't have any good pics of this yet, but I'll be sure to take pictures once I get my tie rod extensions from Jack, so I can test throughout the full range of motion (lock to lock, from droop to bump). I'll report back. If it doesn't work, back to the drawing board!

And Merry Christmas!

Just noticed your diff mounts - you kept the rubber bushings at the nose of the diff but hard mounted the aluminum rear cover.
That's asking for troubles, the rear cover will probably break that way.
The original ford rear mount has a rubber bushing as well, so if you keep the rubber up front you should keep the rubber in the rear mount too.

Moti