LocostUSA.com

Well, I have been a lurker for awhile. Then I started moving forward and bought steel and began cutting it. (The college I work at has a great cold saw so cutting consistent accurate angles was a breeze). I was also practicing my welding, I thought I was ok at it but proved myself wrong. (I have a bucket of test welds that just will not do).

Last week, I had a chance to drive down to southern Oregon with a friend to pick up a car, and I thought I could stop by Kinetic Vehicles to pick up a nose cone. I met Jack and got to learn a great deal about the cars and sit in one (much more revealing then looking at the book).

Well, in the end Jack and struck a deal for him to sell me his very last CMC frame (a classic book frame). A week later (and after one hell of a drive) I now have brought this frame home and set it up in the garage. 

Why is it the perfect CMC frame? I did not have to deal with CMC, I bought it from the honest, knowledgeable, and gracious Jack McCormick. And it is at my home!

I am in it now!
JEB in Olympia Washington

Congrats JEB. What do you have planned for it donor wise?

Yes, just had a Stripper Party!
here is my email to folks!
Hello Friends,

I am beginning a new automotive project and I sure could use your help. I know this is short notice, but I am inviting you to a work party at my house this Saturday beginning at 10:00 a.m. I have a Miata (not my wife’s) that I would like to strip this weekend. (What were you thinking something else?) I would like to get it done before my wife comes home from China. Ya, ya, I am going to tell her.

I will have coffee/tea, and pastries as well as hamburgers and vegan chix patties, ext. I will also have basic tools.

You should have some metric tools, grinders, cutters, gloves, etc. Please RSVP if you can come over, so I can get an idea of who can come.

We will be there, hope you are too!

Thanks ~ JEB

PS - I will add photos from the party as soon as I can.

Now I have a stack of Miata parts in the garage for the suspension, seats, and such. I am still trying to decide if I will go with a big street port rotary or the Miata engine.

My plan is to go with a solid axle in the rear from an Rx7 (the CMC frame I have is a classic and is build for the straight axle).

I do have a ton of other questions:

•Has anyone used Miata pedals in their build?
•Where is a good place to but the shocks?
•Is there a less expensive alternative for the shocks?
•Do you find the high sides of the car to hit your elbows? (I know many cars have angled pieces right beside the drivers and passenger).
•Do you use anti-sway bars in the front or rear?
•Did you use the stock oil pan or did you modify one to be shallower?
•How high is your engine mounted in the frame? Would you be willing to take a measurement? Say, how high the center of the crank is above the frame?

Anyone have ideas?

Jeb, are you going to just chop the rear off the CMC frame and graft on the Miata rear subframe? The drive is a few thousand miles too long for me otherwise I'd be there for the party. Just remember to take great care removing the wiring and to PROPERLY label EVERYTHING.

I'm trying to put together a FAQ that should answer most of you Miata donor related questions.
*edit* I see you treed me Jeb and preemptively answered some of my questions.

CUT OFF THE REAR! I did on my coveland frame.... poor photocopy of a CMC frame. Using the miata rear subframe.

The pan on mine looks like it is going to hang 1.5-2 inches below the frame.

That's right about where mine is. On a related note I scraped my pan across a speed bump for the first time yesterday.

Ok, it is raining and I have more parts in, so…

Since I do not want to stand in the rain and cut my donor Miata up with a Sawzaw, I think I will give my front suspension some time. Here is my first try at setting this up and my fist try at measuring X, Y, and Z axis’s.

Point..........Dist CL..........Dist Frt ..........Height
A................204...............330................132
B................635...............180................170
C................204............... 36.................132
D................297...............273................304
E................588...............193................375
F................297............... 91.................307

Hub to CL 723

The hub block is set at 1.5 neg camber
The upper ball joint is 13 mm behind the lower
Ground clearance is 3" with 20" tall slicks

All of the measurements are in mm. A, B, C is the lower control arm. C being the closet to the front and B being the ball joint. D, E, F is the upper control arm F being the closet to the front and E being the ball joint.

What do you think?

In the picture above the center of the lower balljoint looks to be above the inboard mounting points. You want to set it up with those links parallel to the ground at your static ride height. In your case, since the balljoint is well above the bars of the lower arm, at ride height you should see the arms slope slightly upward toward the center of the car.

Thanks Chet,
So would it make sense to put a spacer between the ball joint and the lower control arm? If so, how think? Or, do I need to do something else?
What do you think?

No...the location of the actual arms is irrelevant. It's the line between the pivots (LBJ and chassis pick-ups) that matters. You've got to move the LBJ or the pickups.

If your tire diameter and uprights are fixed, your only choice is to to move the chassis pickup points. You can do that by changing your ride height, or by cutting the points off and moving them on the chassis.

BTW, I'm not saying that you DO need to move anything...just commenting on HOW you would do it. Have you plugged your numbers into Wishbone or a fancier program? Or drawn a paper-doll/string computer model? If not, check out the stickies in the "Suspension" forum and study up for a while. (Unless Jack handed you a solution already figured out, in which case you're probably doing better than most of us and you can advance directly to "GO!")

As for your other questions, I'll take a stab...

I've got 4.5" of clearance under my +442 frame. The stock Miata oil pan hangs 1" below the frame, and I'll have a skid plate of sorts so it's not the first thing to hit.

QA1 has some good single-adjustable coilovers for about $170 each...probably about as cheap as you'll find new. Koni has something similar. Add $100 or so for double-adjustable. Try your favorite race shop, such as www.SummitRacing.com .

I thought I'd save money by building a pushrod system with some really nice, free Hyabusa shocks. If I paid myself Chinese sweatshop wages, I'd have saved money just buying suitable coilovers! I've got around $150 in bearings alone.

You can read more than you want by clicking on my WWW link at the bottom of this post.


Welcome aboard,
-dave

Here's what I was trying to say. A picture's worth 1000 words right? If I were you I'd just raise the chassis until they are level.

Thank you for your quick responses!

I see, I will need to move the brackets up 1 ½” or increase the ground clearance 1 ½” (or a combination of the two) in order to get the lower ball joint and mounting point to match.

I just got the datafile to open in Wishbone, now I will see what I can do with it.
Thanks

I wouldn't modify any metal until you get it designed on paper.

Then again, I spent 4 months designing mine, and who knows if it turned out any good?

-dave

ps. Boy, you're not going to have to etch that frame before the POR-15, eh?

Heck yeah. I wish my frame had l looked like that before the POR-15 went on.