Hey all. Does anyone have the width of the rear lower control arm at the subframe mount, and the bolt size? I think its about a 14mm dia bolt, and I don't recall the spec on the lca mount. Trying to source a few pieces for custom LCAs.

Nick

Here's what I'm trying to do:

bushing rod end from Speedway Motors, America's Oldest Speed Shop
http://southwestspeed.com/?sec=view_...d Male Threads

Related Accessories - QA1 Linkage Adjusters

Somewhere in this mess is the stuff I need for the control arm. I think the 2 3/8in wide rod end might be the ticket.

 

Mine measures right at 7mm, inside.

If you're going to all that trouble, I would use a good rod end instead. Less compliance, more room for for and aft adjustment, and smoother suspension movement.

 

Oh, that must be the steel thickness? I guess its hard to translate pictures into words sometimes. I made a very poor drawing, using a gent's photo which I really like. cleanly made control arms.

Also, I want to stick with rubber/poly/delrin bushings of some sort, due to NVH. I also do not like rod ends for wearing out and routine replacement possibility. At least not in this area. Maybe on sway bars.

As with some of my other parts, I will include a fully spec'd drawing when I'm done so someone could copy it. I enjoy blueprinting, its fun for me.

 

according to this, the Rear lower control arm pick-up points are 70mm. That sounds about close, 2-3/4" also. Anyone verify?

http://enderw88.files.wordpress.com/...olpickups2.pdf
Drawings | Mechanical Daydream

 

I measured a couple of rear subframes and got a dimension of 2.78-2.79" bewtween the flanges on the subframe. I also measured the lower control arm bushing inner sleeves and got 2.76" consistently, which is understandable, they are machined parts. 70 mm is approx 2.755, so I assume the 70mm dimension you speak of is the actual bushing sleeve dimension, not the subframe flange spacing. You're apparently building the arms, so the 2.75" or 70mm should be good, and if everything else goes well, they should actually fit in the subframe.

Thanks for the drawing package, it pretty much corroborates the numbers I came up with using a height gauge on a surface plate. Would be nice to have the rear control arm key dimensions just to round out the package.

Nice pic, by the way

Mike

 

Gotcha. I found one set of rod ends at 2-3/8in, so this would require a .38" spacer, or .19 on each side, roughly 3/16 of an inch (.1875) on each side. That gives me a total of .005" of play between both sides. That's pretty close to cake+eat it too.

Just for curiosities sake, do you have the bolt OD, or ID of the bolt holes on the subframe? I'm guessing I can just adapt it as I go, but it would be nice to know the I.D. and sleeve size for bushings I will need. This shouldn't be terribly hard thanks to off the shelf stuff, and having a good jig made from miata lcas.

*I just noticed your sig. Jim showed me that site just recently, but I saw your car domain from an earlier LS7 build on Miata.net. I followed that guy for a while, I haven't heard the status as of late, ever find out what happened? Btw, I really like the control arms you built. My original design was going to be very similar, till I found these rod ends. I was working with tie rod end pieces for a Dodge as adjuster before. This setup will be more simple to use and build for me, I think.

 

I am REALLY glad to have found this. Should make life easier. Couldn't find a pipe wrap-a-round that will suit 1" pipe. Which is my choice for the LCAs. Mike, I might basically do what you did on the upper, with minor differences.

Making perfect pipe Saddle cuts with a bandsaw or chopsaw

 

I assume you mean the inner cam adjusting bolts? Bolt diameter is nominal 12mm. Actual measurement is 11.88mm or so. The holes in the subframe are the oblong holes for the adjustment, they measure nominal 12mm X 24mm.

The guy with the LS7 got to the point of adapting the hubs and brakes, I traded some info back and forth with him, then he just stopped communicating and posting. He also had an LS RX-7 as I recall. Silicone Boy was his forum name, because he was a plastic surgeon. Maybe getting his hands dirty was affecting his business

Mike

 

Yes, that is correct. Its unfortunate he quit updating, his work was great. Not surprising considering he works with his hands every day ;-) Its where I first caught some of your posts and work.

At 11.88mm, My closest bolt sizes are 15/32 or 29/64ths. So, not likely. Go up to 1/2in at 12.7mm, I could just drill the holes out and do that, for a tight fit. I'll obviously have adjsutment already built in and won't need the cammed bolts/holes. Is this what you did, or did you just throw something in and snug it down? I've even considered welding in steel to take up the 3/16ths or so of gap between the rod ends I've chosen and the factory mounts.

I'm about ready to pull the trigger on the pieces. When I get home, I've planned to redo this, tackle mounting the gas pedal, ecm, fuel pressure regulator and tank lines, and a variety of other little projects while waiting for the big parts to arrive. Pretty excited.

 

I used the "inserts" from the stock Miata rubber bushings. I remember cutting off the rubber and wire brushing the insert. I made bushings from Delrin, machines like butter, and you don't have to worry about squeaks like urethane. I did buy some urethane bushings, tho, and they came with nice shiny new tubes, which I never used. I used the stock Tbird rubber bushings at the lower outers, made a custom offset Delrin bushing at the top, because the upper part of the Tbird upright is offset more than the Miata.

I kept the inner adjustability for a reason; part of the initial rationale for the outer adjusters was to make sure the tread width was right for the axles. This was a time when the FFR axles were either unknown or in their infancy as applied to Miatas, and I wanted to be able to "set" the tread width and still have the full range of stock adjustability. Having the option has proved handy a couple of times, it's somewhat easier to set the camber with the top adjustment as it pulls the top of the tire inward as it tilts in, more so than just the bottom adjusters.

Mike

 

That's an interesting Idea on reusing the lower inner bolts/sleeve. I might consider it. The adjustment should be pretty easy on the design I've got, though. You don't think I will have full range of adjustment with this setup? I understand now, your idea was basically to have an extendable upper/lower set to move the tire in and out, while still being able to use factory adjustment procedures for alignment?

Noted on the upper T-bird piece. I'll have to do some thinking on that one, too. I'm getting close to ordering parts, but waiting back from Speedway. I found a good, premade 2.4" by 1/2 piece I may go with, otherwise speedway seems to have forged or stainless steel 2 3/8 wide pieces with 1/2in bushing insert and 3/4 thread. I think 3/4 is as small as I'd go for strength.

Can't wait to get working on this, I'm going to be putting a few things together in a drawing and cad program because I've got nothing to do over here!

 

Tha stock range of adjustment is 12mm or right at 1/2". So you should have no trouble meeting or beating that.

Btw. I'm not ignoring getting you the dims and angles for the lca. I have another car parked on the lift right now, so it's just a bad time. I guess you have the spacing now anyway.

Mike

 

Well, all I really needed was the inner mounts. That way, when I get home, parts are at my door and I will start from there. I am not so confident in my fab/welding skills right now, its been awhile. But If I jump into it, we'll see how it goes. I have a few phone-a-friends I can use if I need help I'm thinking.

As usual, my mind is on every piece of the car all at once, so I'm juggling the engine build, transmission build, rear end, and wiring all at once in my mind. Trying to focus on just the rear and engine right now, and worry about the rest next time I'm home. The trans is a pile of parts, but I'm doing the SSR output shaft upgrade so that it will hold up to the motor.

 

So I ordered some samples. I got one like this :
Southwest Speed - Manufacturing, Warehousing, and Distributing Race Car Parts Since 1975.

And I'm looking at getting some roto-jonit/del-sphere/johnny joints, to check out. Has anyone tried these before? I'm wondering how they will work, haven't found any examples in a double wishbone setup yet.

http://www.spohn.net/shop/Del-Sphere...d-Threads.html

http://www.4lowparts.com/shop/currie...t-rh-1-thread/

Roto Joint : UMI Performance, Inc.