LocostUSA.com

Droop stops/limiters are not usually needed. Tough to find springs soft enough to provide any pressure on the seats at full droop and still have enough rate to suit most builders. I would expect to weld bolt tabs on the LCAs.

Eibach sells universal bump stops sets that are reasonably priced and can be trimmed as needed for fit and rate. Most are a high density yellow foam construction but I'm sure your shock eye bushes will work fine. You can also find bump stops for struts easily but often the holes are too big due to the larger shafts used in struts.

https://www.summitracing.com/search/par ... =bump+stop

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Finally making some progress on this... I found a local fabricator in late January to build the new LCAs, I figured 4-6 weeks... almost 4 months later they're finally here.

So far, best I can tell, on initial assembly, things are looking peachy. I'm getting a maximum of ~+5* caster on both sides and camber is in the -1*-ish range, but I didn't consider the added LCA length and I'm running out of thread engagement on the upper ball joint (rod end). Something else for the to-do list.

Because the frame has mounts to accommodate a 2-ish inch wide bushings I've now got a bunch of fore-aft adjustability/clearance to fill... curious what's the "best" way to locate the rod ends on the bolts?

I'm thinking maybe the rear is located with spacers/shims to fix the rear heim inner solid and allow the front to float axially, or do I want both front and rear firmly located axially? I'm concerned about axially loading(binding) the rod ends. Or do I want fully threaded bolts and jam nuts?

Fixed with thick walled spacers as well as select thickness washers if needed to local the lbj thrust load the lcaps evenly. The spacers closest to the joint are usually tappered to ensure the joint body does not contact the frame flanges through the range of motion. If the bolts are 1/2 inch, I'd use 3/4 dom with a 1/4 wall. Black pipe is suitable depending on the bolt od.

There is always some clearance between the bolt and the flanges and the bolt and the joint so alignments are done with the lcap bolts already tight. There is usually some clearance between the joint spherical and the outer race in the body but all that can be done is to buy better quality joints and use rubber bonded washers to help keep dirt and water out of the joints.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Thanks! Allowing the front joint to float axially didn't sound right. The bolts are 5/8" OD, 1/2" Sch40 pipe is .622" ID but only .84" OD., seems to be the only pipe option for a 5/8" bolt. The joints are FK brand with teflon liners, there's no play between the ball and socket currently. Looks like I need to do some careful measuring and get a few spacers made.

That sounds perfect. Using a tree shape, carbide, double cut rotary file in a drill (typical porting bit), remove the weld ridge inside the pipe and deburr/radius the inside corner after trimming to length then belt sand the od and paint. You can use a small metal carpenter square to check the ends square and a bench grinder, minilathe, chuck with a diy arbor in a drill press, etc.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I learned my hand-held tubing cutter was able to cut the 1/2" pipe much better than expected. I've got the spacers and shims sorted to secure both front and read rod ends nicely. Which leads me to the next 'issues'...

1) With everything assembled, the RH UCA & LCA are parallel where the LH arms are not, I would need to add ~3/16" spacer to the top of the LH upright below the UBJ to get them parallel, right now there is ~1.5* difference between the UCA & LCA... Best I can measure all the parts are identical R to L, but something is off somewhere... I assume getting the control arms parallel is more pertinent to good handling that the distance between the ball joints?

2) Spring rates and ride height... My initial goal is to get the car to sit with the LCA's parallel to the ground, which will give ~4.75" clearance from the frame bottom to the ground with my current tires. The car came with 10" 350lb springs installed, two problems here - the car is too light to to get the LCAs parallel, even with me (~210#) standing on the front and at full droop they come apart. If I screw the spring seat up enough to keep them together the LCA's are a long way from parallel. I have only ~4" of wheel travel and I'd like to use as much of that as possible.

Seems like I need a taller, softer spring... I have a set 12", 110# springs that were original to the car and a set of 8", 350#. The car was a road racer most of its life, so it didn't need the travel/clearance of a road car. I found the spring rate calculator, but it doesn't seem to work with inboard/rocker arm suspension.

Suggestions welcome, or should I just start buying springs and see where they take me?

It could be the photo angle, but it looks like both control arms [upper/lower] appear to be converging??? Do you know your camber gain per degree of roll. You may need to add spacers to the UCA top joint.

Make all the parts equal (overall), and fix the frame if it isn't.

Make sure the ucas are the same length and not bent (angle protractor), the coilover spring seats are adjusted to the same eye to eye length which is not necessarily the same seat position. Coil springs are paired when new if bought as a set but they do not maintain exactly the same rate. Too many variables.

Check the ucaps and lcaps for being in the correct location in the frame horizontally, vertically, and fore-aft compared to a fixed point on the vehicle center line. A center punch or small hole as a datum would be a good idea for repeatability. A large, metal carpenter square is handy to keep the dims 90deg. You can put masking tape over the square to write on with a pencil, then use. You are comparing each side rather than trying to precisely measure anything. Measure the frame from the center and use a square for check the height dims and repair the frame as needed.

The tie rod boss on the LH upright looks twisted to me compared to the other side. Could just be the pic. Easier to see if you put a 3/8x3 foot threaded rod through the hole with washers and nuts top and bottom to snug it up to the boss on one end of the rod. Bend it back if needed with the 3/8 rod or slip on a piece of pipe if the threaded rod is bending. Make it the same as the other side. Parallel to the upright is not always where it should be.

Shim to make the fabbed upright ubj to the spindle center the same for both sides. Otherwise, it's like taking a medication with lots of side effects instead of just correcting bad habits, more effort to go around a problem that meet it head-on, cart before the horse, etc.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Davew - I'm new to the depths I'm finding myself is and not sure what is meant by 'converging', is it the same as not parallel? If so, the LH side is. As measured with my $30 amazon angle finder the LCA is horizontal where the UCA is angled down (gets closer together as it nears the wheel).

Camber gain on the RH side, as measured on the caliper mount plate, using a floor jack to raise and lower the LCA in one inch (floor-spindle) increments. With the U&LCAs horizontal I'm getting 0.8* camber, one inch up or down is 0.9*, one inch lower is 1.2*, and one inch higher is 0.95*. The left side shows even less gain, next to nil.

Working thru all this and staring at my cad model I'm beginning to understand where the problem is. In the notebook I got with the car there is mention of hitting a barrier with the RF wheel, but the frame appeared straight after, but either it took another hit or wasn't straight. The image below kind of illustrates what I think is happening with the frame and what's causing my L/R discrepancies... But in the short term I just need to get this part "close enough" to assess the motor and drivetrain, then prioritize efforts/$$$

Mv8, I'll get to measuring again now that things seem pretty close. I'll double check the boss too, I think it's straight, but I was puzzled as to why they are clocked differently. As seen from above, assuming forward on the car is 12 oclock, the RH boss is pointed at 12 oclock, where the LF boss is pointed to ~10:30. The adjusting tubes are the same length, and the inner TRE's are centered on the frame. I'm assuming it's the result of a pre-CAD, home-shop design-build... just another head scratcher for me.

In the static ride position you would typically see the upper control arm angled upward towards the top spindle joint, by as much as 22*, depending on the camber gain you are shooting for. Most front suspensions will be in the range of .2 to .3* of camber gain per inch of travel. A shorter upper arm or more angle to increase the fore shorting will be needed to get in the sweet spot. Some gain can be corrected by setting up negative static camber, but you will increase "rapid" tire wear and you end up with early front tire lock-up under heavy braking because of reduce tire contact. I would bottom out all the threads on the upper control arm joints first, and see what you end up with. The easiest method may be to use a spacer with a longer bolt on the spindle that would increase the UCA angle. With your CAD system, it should not take a lot of time to run thru your spacer options. You do not want parallel arms, because you end up with the camber the same as the body roll. "Most" tires will transfer max grip in the -2 to -2.5* camber range. If you can not get it in that range, do not worry about it. Some is better then none.

I really appreciate the info! I've spent the last 2 days measuring and remeasuring and sometimes getting the same measurements Biggest trouble is finding the U&LBJ centers, and those relative to the spindle.

I've plugged the numbers into vsusp, and it's results aren't jiving with what I see, but it really shows the affects of minor changes and your right, adding a spacer below the UBJ will smooth some of the spikes on the graphs.

Is there a rule-of-thumb practical limit to how long a spacer I can add? The bolts are 5/8-18AN, I suspect I could add up to an inch without marginalizing other things strength-wise, assuming no interference elsewhere.

Just an update, between the summer heat and a variety of non-auto related calamities progress slowed a little, but yesterday I finally took the Rotus off the jack stands - woot!

I was exceedingly happy to find my front suspension assembly/alignment measurements are in the right ballpark at least.

I've got 1.5* camber, ~4.25* caster and 1/32" toe in.

I decided to enlist the help of specialists to help me assess the motor/drivetrain (and everything else), Esses Racing out of Buda Tx. They're going to pick up the car in a week or two... double woot!

My Two Cent Tech Tip (probably not new and might be worthless) While reading up on DIY alignments/toe adjustments it was suggested to roll the car forward and back occasionally. I don't have the room to move it more than a foot or two so instead I used 2x cheap amazon nylon cutting boards under each front tire which allowed the tire to slide (turn L-R) easily on the floor.

You might try putting some oil between the two sheets. but I found there was still too much friction for small adjustments. The best I found was to drive it 100yds and re-check. Great looking wheels and tires!

oil...duh, I honestly didn't consider that, I was thinking baby powder or dry graphite but they seemed to move easily enough - but this was my first string and tape measure alignment, so....

Thanks on the wheels, too bad the rears don't match and they are 10" wide. This car has 4x4.5(114.3) bolt pattern, not many options out there any more. I do check ebay occasionally as I'd love to find a couple Enkie's suitable for the rears.