Any suspension, no matter how poorly designed, can be made to work reasonably well...

TL;DR: Are we really sure that good dampers, reasonable springs, good sway bars, and a set of fresh, possibly polyurethane bushings wouldn't make this thing behave pretty darn well?

What mid-70's European Ford? Escort? Capri? Cortina? I don't know which were Mac strut, etc...

The easiest thing is: What solutions already exist? I assume you're not the only person with this issue, and that in the last 40 years some folks have thought they'd like the wheels pointed the right direction in a reasonable orientation to the ground, AND to have that lovely spine-saving, often-grip-improving suspension involved.

Is it so low that you're all out of travel, or is it just so over-sprung that it doesn't move? If the former, sometimes shorter strut inserts provide additional travel (I suppose sometimes requiring the body to be cut down). E.g. the BMW 2002 with Rabbit strut cartridges.

Are bigger sway bars available? Good dampers?

A lot of cars do okay with mediocre Mac strut geometry, camber plates dialed up to match the level of aggression required (a mentor with a fast autocross BMW 2002 stopped seeing benefits after 5 degrees static negative camber, but I'm sure it would've eaten tires like candy if it was a daily driver, and surely sacrificed some braking).

Car is a Capri- but could be a Cortina, which the Capri is based on, or a 1st generation escort. All used similar or the same parts.

Currently has Bilstien strut inserts, ROK Stock front springs and a 1" bar replacing a 5/8" (OK, a 16mm) front bar, and polymer bushings. Installed all circa 1980, the car rode like crap then, and nothing has changed. Except I weigh 60 lbs more. OK, 70. I was willing to live with it 40 years ago, today, not so much

I believe there is no travel left in the suspension. When you try to bounce the fender, there is (to my lame eyes, no relative motion between the fender and tire.

I have spoken to the Oracle for Capri in the US. He tells me I trade ride for handling. I don't like the rates I'm trading at. I also am not a fan of his business model, even though I do trade with him. Maybe I need to look further afield.

I think get it- body roll affect on camber is a bigger problem in a strut car than an SLA. These cars have a VERY short track arm- just 9.75 inches, so camber changes are worse than if you had a longer lower arm. I don't want hella cool wacky wheel camber. I want my tires to live

I anticipate I will need to cut down a strut- guess I should call Koni and see what's available. That would at least give me suspension complianc back.

Anyway, Mo Later
 

What spring rates are you at?  I'd expect something in the ball park of 300lb-in springs, give-or-take.

Are you actually -on- the bump stops?

I'm a big fan of short bodies struts, and the appropriate spring rate.  Even running high spring rates is more comfortable a ride than hitting the bumpstops.

Hi there fellow Capri driver :-)

I am the first (no, not really the first you get my point) to agree that the stock(ish) Capri front suspension has severe shortfalls. Bad camber compensation, not enough caster, large scrub radius when you add reasonably wide wheels and some bump steer on top of that.

But fitting something else that is magically better? The "best" solution I have seen and driven, is probably Sierra struts with adjustable track control arms. For you (in the US I take), that would mean XR4Ti struts. In Europe, new adjustable Sierra TCA's are easy to get - not so sure about the US. Correctly fitted, this solution will aid all the problems mentioned above and is almost bolt-in. Depending on desired poke/stance/wheel width and fender treatment, eccentric or adjustable strut tops are recommended to get the wheel where you want it. You will also need to use a modified ARB for caster adjustment or go straight to tension struts or compression struts.

The cars I have driven used a "standard" aftermarket Sierra strut, usually a coilover from GAZ or similar. But a tailor made strut would be great to give you the correct height and suspension travel.

SLA is nice but going to a Mustang II setup they way they usually are would, IMO, be step down at least in handling. For an SLA to work in a Capri you'd need serious inner wing modifications. I would be tempted to look at one of the "modern" designs with a high upright and the upper arm above the wheel. Nissan 350Z comes to mind as a possible donor.

Gustaf

Speaking from experience: Anything can be made way way better if you're not afraid to do some fabrication or get custom parts.

How I'd go about it:

1. Get a good idea of what you currently have and what it's doing under load (acceleration, braking, cornering). I like to study pictures of the car on track. Specifically looking at the tires vs. pavement and body, angle/pitch of body, front vs rear and any other visual clues I can find/use.

2. Realize what needs to be changed in order to improve it. Specifically the geometry... caster, camber, toe, travel (too much/not enough) Note: I leave dampening out of this step because I have noticed that if you can get a suspension working well on ok/decent shocks/dampening then when you step up to serious/high quality ones they'll be a night and day improvement vs band-aiding the base problems.

3. Make changes the improve the geometry. As mentioned about about caster/camber for instance. What come to mind immediately is that a tall lower ball joint could/will do several things. Lets say we use a +1" length lower ball joint. This will change the angle of the lower control arm by moving the wheel side down. This then results in more camber gain during compression as the ball joint will/should be traveling away from the center of the car (up to the point of level). Depending on the current tie rod angle this may increase or decrease bump steer. I know this change lowers a double A arm car but not sure about the strut (I don't think it will). Next would be an adjustable top hat for the strut. Preferably a spherical bearing type. And more importantly an offset mount location to increase caster. As a fabrication guy I would also look at making my own lower control arm (yours will need to consider that sway bar as part of the arm too) and change the length and offset (front/rear via sway bar) in order to add caster and camber as needed or limited. Also everything should be low friction joints and poly or bearing "bushings"

4. Once changes are made revisit step 1,2,3. Then if things are looking like they have good control of the tire then add a great damper. Likely the overall travel will be reduced which is just fine because at this point you know you're getting the best out of the tire over a larger travel amount so reducing that window isn't going to loose anything. Compared to a good damper when you have no idea about maximizing the tire grip could have the suspension doing all kinds of bad things but now its very difficult to see with a much reduced travel window.

Oh, and increased caster can compensate for the massive caster loss MacStrut does on turns.  If you can modify things to max out your caster, things can go better.

   Often front wheel drive race cars do not use a front sway bar,  some front drive cars use the sway bar as the forward suspension links.  So sometimes removing the front sway bar would require some creative updates.

      Front drive you brake in a straight line, no trail braking.  Then as soon as you turn in, you start adding power, the front wheels then pull the car thru the turn.   A front sway bar will lift the inside front wheel, and you will have wheel spin when you need to add power.

      You get you front sway control from stiffer front springs.

      Typically a front drive car will have a large rear sway bar, often lifting the inside rear wheel off the ground thru a turn.

     With the suspension tuned, you won't have much wheel spin or a need for a limited slip diff, unless you are making a lot of power.

SkinnyG (Forum Supporter) said:

What spring rates are you at?  I'd expect something in the ball park of 300lb-in springs, give-or-take.

Are you actually -on- the bump stops?

I'm a big fan of short bodies struts, and the appropriate spring rate.  Even running high spring rates is more comfortable a ride than hitting the bumpstops.

Spring rate-  I fit the parts in 1981, so ummmm, I forgot. Think 300 may be a bit higher than what I want to go, but I'm willing to get a couple sets of springs to try to bring rate in

Actually on the bump stops- I weigh 270. When I lean on the fender, there is no movement between the   tire and fender, but I see the sidewall at the bottom of the tire abulging. So on the bumpstops- I'm going to guess yes.

Lest you think this is a case of the springs sacking after 40 years- This was the condition when I installed the springs many years ago. That detail I am able to remember

In reply to twentyover :

I think it's important that you get a look at the available travel left on the struts rather than relying on apparent motion when you lean on it. Between poly bushings with perished lubricant, tire scrub, and other losses, there's just so much room for error. And if you're talking about a rework on this scale, having a really proper look at the starting point seems vital.

    You want to ensure your not sitting on the bump stops.  If on the bump stops, then you don't have springs at all.

        If hard to see with the wheel on....   Remove a wheel and put a jack on the suspension and lift till the car is level, just be careful don't get under the car at all, as this may not be very stable.

      You might be able to trim the bump stops, but they are there to keep the shock from bottoming out.

A pair of pickup points grafted to the chassis and a custom control arm that uses two pickup points at the chassis end seems like a great general idea of improving the situation.  If that sounds like a doable project, that's probably where I would go.  I wonder if moving to a Fox Mustang spindle and strut would be not impossibly hard and get you some better options for brake rotors and calipers.  I also think that bearings would be easier to source with the Mustang spindle over the Capri. 

therealpinto said:

Hi there fellow Capri driver :-)

I am the first (no, not really the first you get my point) to agree that the stock(ish) Capri front suspension has severe shortfalls. Bad camber compensation, not enough caster, large scrub radius when you add reasonably wide wheels and some bump steer on top of that.

But fitting something else that is magically better? The "best" solution I have seen and driven, is probably Sierra struts with adjustable track control arms. For you (in the US I take), that would mean XR4Ti struts. In Europe, new adjustable Sierra TCA's are easy to get - not so sure about the US. Correctly fitted, this solution will aid all the problems mentioned above and is almost bolt-in. Depending on desired poke/stance/wheel width and fender treatment, eccentric or adjustable strut tops are recommended to get the wheel where you want it. You will also need to use a modified ARB for caster adjustment or go straight to tension struts or compression struts....

...

SLA is nice but going to a Mustang II setup they way they usually are would, IMO, be step down at least in handling. For an SLA to work in a Capri you'd need serious inner wing modifications. I would be tempted to look at one of the "modern" designs with a high upright and the upper arm above the wheel. Nissan 350Z comes to mind as a possible donor.

Gustaf

Heya Gustaf- I re-read your thread before I posted...

The car has been out of service 20 years, parked in the barn in MI. I retired and am moving back to Cascadia (Washington state, about 30km (18 miles for us 'Murkins) east of the local highway summit.) Putting together a 4l v6, T5Z transmission, and an lsd on the Atlas axle.

Right now I'm focusing on front suspension, since the way it's currently set up sucked soo much.  If I don't make it the first time around, there's time for a second. At this point, I'm not fixated on any single solution, If I can get where I want with few changes, that's better than making changes just to make changes.

I think at this point I'm really fishing for suggestions to improve the Mac Strut. You suggest Sierra, am I correct in understanding that the Sierra uses clamp or bolt on spindle? Never paid much attention to them when they were sold in the US. Never seen a US built adjustable TCA- most of the Brit vendors don't ship these parts to the US, I think because of the liability situation. This doesn't scare me- easy enough to fabricate

Front ARB's modified for caster adjustment are available here-a bit spendy, but available. I've dallied with the thought of a tension or compression strut to isolate location from anti-roll function. Planning on using a high positive offset wheel- a primary goal here is to do no more than roll fenders. I plan on a set of caster/camber plates to help build more caster in- may eliminate the need for an adjustable TCA?

Want to start working on the car when it moves out here from Michigan in November, trying to collect parts as much as possible so I'm not sitting on my hands.

asphalt_gundam said:

Speaking from experience: Anything can be made way way better if you're not afraid to do some fabrication or get custom parts.

How I'd go about it:

1. Get a good idea of what you currently have and what it's doing under load (acceleration, braking, cornering). ...

2. Realize what needs to be changed in order to improve it. ....

3. Make changes the improve the geometry. As mentioned about about caster/camber for instance. What come to mind immediately is that a tall lower ball joint could/will do several things. ....

4. Once changes are made revisit step 1,2,3. T...

Thanks for your input Asphalt- read your thread when I saw it a couple weeks back, Cool project, I had a G body elCamino many years ago. Many Many years ago. Insert wistful sigh here,

OK, right now the primary issue is inadequate travel. Until that's resolved, I don't think I can even come close to doing a dynamic photo analysis .

What I'm starting with-

Lower arms are cast steel, with ball joint housing machined in. And short. Like 9 3/4" short. Which exacerbates the problem with adding positive camber in roll after the outside ball joint gets above the inner pivot. WHy the Oracle says the suspension needs to be snubbed down to prevent roll. And I agree to s certain extent.

and the adjustable TCA referenced by pinto (all images shamelessly purloined from the internet)

On tall ball joints, not really possible with this, but maybe raise TCA inner pivot point in the crossmember. Need to check bump steer and a change like that will impact, magnitude unknown.

Or maybe it is possible, if I were to replace ball joint with spherical bearing and have a longer taper section higher than the factory deal, along with a straight shank through the ball.

 Anyway. appreciate the input, and feel free to call me out if you think I'm heading down the path to the dark side.

Jesse Ransom said:

In reply to twentyover :

I think it's important that you get a look at the available travel left on the struts rather than relying on apparent motion when you lean on it....

Car is on stands w/o wheels in MI. Engine is out, so may be difficult at this point to check for suspension travel. Agree eyeballs on a sidewall is hardly a quantitative measurement

TED_fiestaHP said:

    You want to ensure your not sitting on the bump stops.  If on the bump stops, then you don't have springs at all.

        If hard to see with the wheel on....   Remove a wheel and put a jack on the suspension and lift till the car is level, just be careful don't get under the car at all, as this may not be very stable.

      You might be able to trim the bump stops, but they are there to keep the shock from bottoming out.

Difficulty is trying to determine where the car rests when engine is out and wheels are off. But agree with you

I believe some of the Rabbit folks have worked with alternative ball joints or spacers which effectively lengthen the part of the strut between the spindle and the ball joint, thereby putting the lower arm back into a range of motion that is better with respect to camber change.

I'd be curious as to whether there's existing info out there about this approach, as it seems like it would help with the camber issue, but could certainly introduce other geometric issues (bump steer springs to mind since you're changing the trajectory of everything attached to the strut).

I'd be very careful about selecting such a ball joint or spacers, as that's a very highly loaded and mission critical point.

twentyover said:

asphalt_gundam said:

Speaking from experience: Anything can be made way way better if you're not afraid to do some fabrication or get custom parts.

How I'd go about it:

1. Get a good idea of what you currently have and what it's doing under load (acceleration, braking, cornering). ...

2. Realize what needs to be changed in order to improve it. ....

3. Make changes the improve the geometry. As mentioned about about caster/camber for instance. What come to mind immediately is that a tall lower ball joint could/will do several things. ....

4. Once changes are made revisit step 1,2,3. T...

Thanks for your input Asphalt- read your thread when I saw it a couple weeks back, Cool project, I had a G body elCamino many years ago. Many Many years ago. Insert wistful sigh here,

OK, right now the primary issue is inadequate travel. Until that's resolved, I don't think I can even come close to doing a dynamic photo analysis .

What I'm starting with-

Looking that this my first and foremost concern is the spindles and struts. Its difficult to tell how they attach to each other but the spindles look just so damn outdated on top of what appears to be little to no adjustments for alignment. 

If it was me or I was recommending to a customer: I would seek out a spindle swap with the intention of new custom struts. To find a spindle in the same or whatever bolt pattern you want to swap to is a plus but I wouldn't prioritize it. Priority one to me is get travel back in the suspension. If you're at the ride height you want the place to get it without raising the car is the strut and/or spindle. Raised strut with drop spindle, shorter strut, or both. I'd start with the spindle. All that is really needed is a strut type spindle with lower ball joint attach point. I'd pick of choices that come from platforms with great aftermarket support for brakes, bearings, lower ball joint lengths. I'd probably start with looking at mid 2000s and up Honda on the Civic/Accord/etc. Then I'd look for a lower ball joint option that fits your arm IF the spindle offsets are close. If not then I'd toss the stock arm out the window, get a stock ball joint for the spindle and fabricate a new lower control arm at the needed length to set track width correctly. Also don't forget wheel offsets factor in hear and may get you that longer arm you want while making sure plenty of wheel choices are available. Once that is taken care of a custom strut to achieve travel and ride height will be the easy button. For arguments sake I'd have a go with the donor car's strut since I have zero problem cutting up a suspension mount and moving it, strut tower included. Mostly we'd be talking vertical height depending on the donor strut length, maybe some offset for caster/camber.

If going all out I'd be making lower control arm mounts anywhere they could and be solid. Fabricate an A frame lower control arm. Switch to a conventional style sway bar. Donor car spindles. Custom struts to minimize required work (unless the donor strut came out really close, then I might change the tower for "off the shelf" options). The brake upgrade (even stock), better bearings, parts availability, and lug pattern change would be huge wins on top of fixing major suspension problems.

Another note: looking at the suspension you have the lower control arm pivot looks pretty close to the steering rack pivot. Which is good for minimal bump steer. Moving the rack up or down to match the angle of the tie rod to the angle of the lower control arm and checking it for the smallest amount of change (vs each other) throughout suspension travel will be best case bump steer. Steering arms look to be bolt on also...that opens lots of doors to custom anything by going to a fabricated arm and STD rod end on the tie rod.

Simple and cheap: I'd get a taller spring to raise the car and get travel range in the strut. Then cut and shorten the bottom of the strut to lower the car again. Assuming there is the ability to do so without cutting into the hydraulics and ruining the strut.

The Right side image is an excellent example of modern parts and longer lower control arm. Image source says its 2017 Civic Type R but I don't know if thats left side or right side.

asphalt_gundam said:

trimmed reply for efficiency:...

What I'm starting with-

Looking that this my first and foremost concern is the spindles and struts. Its difficult to tell how they attach to each other but the spindles look just so damn outdated on top of what appears to be little to no adjustments for alignment. 

Struts are non-removable tube housings welded to the spindle. Shock replacement is to remove the guts (Screw cap on the top of the tube) and replace with a damper insert.

Alignment is accomplished as follows:

Toe-  screw the steering rods into or outta the tie rod end

Caster- Loosen the crossmember retaining bolts and beat the crossmember into submission until you reach the edge of the bolt hole. There is no designed in caster adjustment. And caster setting are 0.5-1.0 positive. So almost no caster at all

Camber- There is no designed in camber adjustment. Plug weld the crossmember hole and redrill at a different location. Or use the adjustable track control arms shown in my prior post.

asphalt_gundam said:

Simple and cheap: I'd get a taller spring to raise the car and get travel range in the strut. Then cut and shorten the bottom of the strut to lower the car again. Assuming there is the ability to do so without cutting into the hydraulics and ruining the strut.

Simple and cheap is good. I've found a Koni insert that is shorter than the current insert, I'll use it and cut down the strut tube, probably use a coilover  sleeve for a good selection of sprng rates. Step 1 is beginning.

Traditional method for caster and camber adjustments are camber plates on te inner fender. Alreading planning those

The remainder of your post is good food for thought, think i need to spend some time digesting it. Thanks for the candid input

Yes, the Sierra (XR4Ti) uses a spindle that clamps the strut tube. I have driven a couple of MkI Escorts with this solution. The Escort has the same front suspension only a bit more narrow cross member and steering rack. This really is a simple solution that "works". It also works without having to change everything else...

In the US, parts are not as easy to come by so other parts may well be better suited. A Fox body or SN95 strut would be possible. I had long, hard looks and a lengthy dialogue with the MkII Escort with Mustang V6 and mostly Mustang running gear that someone drives in US rallying - I had the fortune to see that car at SEMA some time ago. But you're in for some amount of fabrication.

A downside of both the Capri/Escort and Sierra/XR4Ti front suspension is that the lower ball joint is integral into the arm so you can't really swap it to change the roll center. I have tried the "RS2600 method" of moving the inner mounting points for the rack (up and out), but you really need to move the rack upwards as well, otherwise bump steer is evil. Since I have YB Cosworth oil pan in the way, I had to reverse that modification.

I am myself very tempted do design a new set of TCAs with a removeable ball joint, probably something like the steering angle kits used on many drift cars. I want more steering angle and I would like to have a ball joint that could be swapped out.

Another possible strut donor is the Volvo 240, and 740. They still have the integral strut tube so it is less ideal in that sense but has some other nice features. The bolt-on console for the lower ball joint means it is super easy to alter roll center and you can also use that to make a new steering arm where you want it. The 740 is more sleek.

When I modified my front suspension it took quite some time to get all things reasonably well in position and I am still not 100% satisfied. But I did shorten the strut tubes as much as I could, and also lowered then in the spindles as much as possible. So even though the car is quite low and I have a decent spring rate the ride is not too bad.

Gustaf

asphalt_gundam said:

The Right side image is an excellent example of modern parts and longer lower control arm. Image source says its 2017 Civic Type R but I don't know if thats left side or right side.

It'd be left side, from the rear - the steering arm is facing you, and most FWD use a rear-steer rack behind the engine.

Fox Mustang bits still sound like a good starting point, knowing that a custom control arm would be needed, because the donor vehicles are common with lots of aftermarket options available to tweak & improve with.  The wheel lug pattern is the same as the existing Atlas rear axle (which the OP has upgraded with an LSD meaning there's sunk costs there which are not insubstantial) which is a nice bonus.  The steering rack on both the Capri and the Fox are in front of the spindle instead of behind and in pretty similar relationships spatially.  Factory rotors are a bit bigger on most or all Fox's and vented instead of solid like the Capri and I'm sure there's a few good brake upgrades when starting with Fox hardware available off the shelf. 

In reply to twentyover :

Do you have details of the Koni insert? 

Racingsnake said:

In reply to twentyover :

Do you have details of the Koni insert? 

Two options available- single adjustable or double adjustable . I'll be going with asingle adjustable, as this is, as stated in the first post, primarily a street car

https://performanceshock.com/KONI_86_series_race.pdf

I'll be using 8610-1436 single adjustable

Or if I get a big tax return, MAYBE an 8611-1257.

Wait, it's not tax season  :(