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

... if you just stop it from moving. Colin Chapman


And mine is really poorly designed.

I have a mid-70’s European Ford with a true Mac- Fear- son strut (lateral track arm, located fore-aft by front sway bar) front suspension. I’ve had the car for 40 years- When it was new, I did exactly what everyone else was doing, snubbing down the suspension. Until all my front suspension compliance was in tire sidewall flex. Seriously, it handled great- well, it handled OK, but tire’s sucked and most of my friends didn’t know what they were doing. Neither did I.


That was then, now is now


I still like the car, but want it to handle and to ride. Did I mention the only front suspension movement was tire sidewall deformation? Have 2 options- SLA and trying to improve the MacStrut. Fishing for ideas on how top improve the mac strut so I don’t compress my spine w/ every Michigan pothole I hit, or someone tell me to toss the strut and start with some sort of SLA, along w/ recommendations. I’ve been toying with the idea of Mustang II, but am aware of at least some of it’s shortcomings due to short A-Arm length

Any takers? Anyone want to venture into the swamp with me?

lets see what you got

Quote:

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Originally Posted by Rod

lets see what you got

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A few pictures of what the stuff looks like

Attachment 178299

Attachment 178300

Attachment 178301


Pictures are off the web, a RHD variant. Hold the monitor up toa mirror and you'll see what my suspension looks like. The car is my avatar, Ask any questions, I'll try to answer more or less intelligently.

Ignore picture below- it wandered into the post accidentally and I can't seem to edit it out

Sorry- double post

so... with a removable k member, I guessing the car is a uni body, so a M2 suspension would be easy and you will get more engine compartment room, because you can cut out the big shock towers the struts went up into

I gotta believe a MII installed backwards and crooked would be an improvement.......is the sway really a tension link for the lower control arm?

How small is this car? MII hub to hub is 56.5"

Quote:

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Originally Posted by dontlifttoshift

I gotta believe a MII installed backwards and crooked would be an improvement

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:lmao:

I'm gonna go against the grain here. Or at least call for thinking twice about it.

Muscle car guys are primed to think "Put a M2 front end on it" as a knee-jerk reaction. That stock suspension (in the pics) looks unfamiliar and weak.

But it's really only "weak" in terms of 3500-lb cars. On smaller cars that design is not uncommon. It generally holds up fine.

"Unfamiliar" is not a great reason to spend thousands of dollars, do a lot of heavy fabrication, and add weight.


An aftermarket M2 front end is probably superior on paper. But how much do you need it? How bad is the stock alignment & geometry? Are you wanting to run wide tires on this car? How is the aftermarket support for that stock front end?

Greg, One alternative would be MOVE OUT OF MIGHIGAN (joking....have a lot of aussie budies at Ford and GM there)

Second suggestion: a buddy with CONSIDERABLE exprience has one under construction with SBF. I will get pics this afternoon.
Meanwhile....until i speak to Rob........Mustang11 is not the way to go....the bodyshell was not engineered to take chassis rail loads, and welding sleeves to cure this is B.S.
I think he cut the inserts out of the struts, found a Koni insert that is compatible. Machine retaining rings for the struts and spring seats for a decent Eibach coil-over spring (from Rod Prouty above) and i'm guessing poly bushings for the sway bar.
For rollcenter improvement, move the lower arm inner pickup point up half inch (this is max without cutting the rail).

More info to come......don't know what he did for steering rack.

fwiw....I'm a retired ex-GM body designer....now fabricator to keep my sanity. Capri was common here in Oz.

mikedc.....props for the breath of fresh air!

Jim Grant
Melbourne Australia
(was SFO '06 thru 13)

Quote:

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Originally Posted by Rod

so... with a removable k member, I guessing the car is a uni body, so a M2 suspension would be easy and you will get more engine compartment room, because you can cut out the big shock towers the struts went up into

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Car is a 76 Ford (Mercury) Capri, it is unibody. The lateral track arms are only 9" wide, the the entire Mac Strut is outside the frame rails, so that advantage of strut elimination usually present really does not apply so much here,

Reason I'm hesitating on an M2 is that my understanding is that the control arms are too short. I did a search here and a member known as sinned was beating up on people who claimed the M2 had pretty good geometry. Dave Pozi apparently agreed (based on my interpretation of his comments.) He also worked with a M2 owner member Alcino to make improvements. And II Much member John (last name I don't remember- Parson(?)) i seem to recali ripped out an installed M2 in his Chevy II for a Katz designed suspension, seem to reason was because control arms too short causing camber gain issues.

What I don't want to do is rip out the existing way too stiff suspension and replace it with a suspension that needs to be way too stiff to handle well

I may be making perfection the enemy of the good here- what say the hive mind?

Quote:

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Originally Posted by dontlifttoshift

I gotta believe a MII installed backwards and crooked would be an improvement.......is the sway really a tension link for the lower control arm?

How small is this car? MII hub to hub is 56.5"

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My understanding is that the original design of the MacPherson strut uses the sway bar as a link for the lower control arm. The Cortina (which the Capri is based on) also used this deal. So yes, it really is a tension arm.

Some have added a separate tension or compression strut to isolate the sway function from locatiion function

Capri front track is 53". According to the self appointed Capri expert in the US (I do give him credit, he knows ALOT of ****) nominal WMS to WMS is 56.25". I was running 15 x 7 w/ 205/50-15 ILO the stock 13 x 5 w/ 185/70-13. So maybe by careful wheel selection I may be able to put a M2 and similar tire under a stock fender- That is one of the hard goals here, no flares, although I will roll a bat if needed

Quote:

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Originally Posted by mikedc

I'm gonna go against the grain here. Or at least call for thinking twice about it.

Muscle car guys are primed to think "Put a M2 front end on it" as a knee-jerk reaction. That stock suspension (in the pics) looks unfamiliar and weak.

But it's really only "weak" in terms of 3500-lb cars. On smaller cars that design is not uncommon. It generally holds up fine.

"Unfamiliar" is not a great reason to spend thousands of dollars, do a lot of heavy fabrication, and add weight.


An aftermarket M2 front end is probably superior on paper. But how much do you need it? How bad is the stock alignment & geometry? Are you wanting to run wide tires on this car? How is the aftermarket support for that stock front end?

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mikedc- I''ll respond to the q's first

How bad is the stock geometry- never plotted camber vs dive or roll- but like all Mac Struts, you need alot of static camber to get good cornering grip, which screws up braking. And you need to snub down vertical suspension movement to keep camber from going crazy stupid. I can change alignment, I can change pickup points, but I can't change fundamental aspects and limitations of the MacStrut design

The reason for my question was that I'm no longer willing to beat up my kidneys to get good handling. If anyone knows how to achieve softer suspension travel while controlling camber I'm all ears- I have a suspension in the car, am willing to change components if I can get a more compliant ride and maintain the same or similar handling.

This was a small tire car- came w/ 165/80-13, w/ 185/70-13 option. I have been running 205/50-15 front and 225/50-15 rear. I would like to go up to 225/50-15 front- so it remains a small tire car at best.

Car will weight about 2850 lbs until you plop my fat ass into it.

Essentially stock parts are available, but the guys in the UK won't ship to the US due to liability concerns. In the US, support is lean.

I'm not opposed to an M2 front end- I've bought most of the parts for one! But before I tear the thing apart, I wanted to hit pause for a minute and make sure I'm not overlooking options. If that means tossing the M2, I'm OK with that. If that means using the M2, I'm OK with that too.

M2 parts I have- Wilwood tall M2 uprights, SPC upper and lower A arms, and Kore 3 hubs. Again, no one is holding a gun to my head saying I need to use these just because I have them.

Tjanks all for your input. Sorry so long winded

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Originally Posted by Falcon64

Greg, One alternative would be MOVE OUT OF MIGHIGAN (joking....have a lot of aussie budies at Ford and GM there)

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Don't tempt me, Jim. I grew up in the Pacific Northwest, then moved to California in my 20's. Career moved me here 16 years ago- can barely wait to escape. Also retired, ex Calsonic (now Marelli) HVAC development engineer

Quote:

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Originally Posted by Falcon64

Second suggestion: a buddy with CONSIDERABLE exprience has one under construction with SBF. I will get pics this afternoon.
Meanwhile....until i speak to Rob........Mustang11 is not the way to go....the bodyshell was not engineered to take chassis rail loads, and welding sleeves to cure this is B.S.
I think he cut the inserts out of the struts, found a Koni insert that is compatible. Machine retaining rings for the struts and spring seats for a decent Eibach coil-over spring (from Rod Prouty above) and i'm guessing poly bushings for the sway bar.
For rollcenter improvement, move the lower arm inner pickup point up half inch (this is max without cutting the rail).

More info to come......don't know what he did for steering rack.

fwiw....I'm a retired ex-GM body designer....now fabricator to keep my sanity. Capri was common here in Oz.

mikedc.....props for the breath of fresh air!

Jim Grant
Melbourne Australia
(was SFO '06 thru 13)

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Plan for me is to keep the Cologne engine- except as a 4.0, T5Z, and an LSD and 3.44's in the Atlas axle. Air, cruise- all the stuff we couldn't afford in the 70's (I've owned the car since 1978.) am currently constructing a torque arm rear- we'll see if that works.

If I go M2, there is one variation I was planning on- Rather than a short shock transferring load to the frame rail stamping, I would use a long coilover and feed spring loads into the MacStrut spring pocket per the original design. Since the upper control arm loads are a fraction of the lower control arm, it should load the chassis similar to a Mac Strut. Probably give me the worst of both designs.

I have seen the steering rack moved up so a notch was required in the frame to clear the tie rod. since that is in front of the Xmember it doesn't scare me

The question will be, does you're compadre's changes achieve my stated goal- retain handling while improving suspension compliance

Looking forward to pictures, if your friend doesn't mind maybe he can send his e-mail address to galanf at juno dot com so I can communicate directly

The mac strut design has been used on some pretty hot cars over the years. The camber gain is never great but there is more to handling than that issue.

Have you driven this car with some really good modern shocks + aftermarket sway bars? In theory that should help control the body lean so you aren't grappling with the front end's weak camber gain all the time. The shock valving should be resisting those kinds of slower G-forces and only "unlocking" on sudden hits (read: bumps and potholes). Ideally the body lean should be limited by the shocks/sways and not by hitting the bumpstops. That's not always feasible depending on the car & ride height.

A 225 tire doesn't seem very narrow for a car that small. Between that and the larger rim diameter, I can see why the weak camber gain is bugging you.

BTW, do you know what the front roll center height is? If it's really low then that will magnify the body leaning problems. (Too high brings a different set of problems.)

Quote:

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Originally Posted by mikedc

The mac strut design has been used on some pretty hot cars over the years. The camber gain is never great but there is more to handling than that issue.

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I guess my focus on the camber gain issue is due to the short track arm length- IIRC it's about 9", I think many of the 'hot cars' are about 50% longer than that. The short length causes more transverse displacement of the bottom of the strut, adding more positive camber in compression than a longer arm adds. Hence the need for more static camber and it's woes

Quote:

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Originally Posted by mikedc

Have you driven this car with some really good modern shocks + aftermarket sway bars? In theory that should help control the body lean so you aren't grappling with the front end's weak camber gain all the time. The shock valving should be resisting those kinds of slower G-forces and only "unlocking" on sudden hits (read: bumps and potholes). Ideally the body lean should be limited by the shocks/sways and not by hitting the bumpstops. That's not always feasible depending on the car & ride height.

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Have not driven w/ modern shocks- part of the issue is parts availability. For instance, Rock Auto (not that Rock Auto is the be all and end all) doesn't list any replacement front strut inserts or cartridges. I'm running a set of Bilstein sport inserts from 1980 (about 23K miles on them) and I believe I've probably damaged them, based on road feel.

The car came with a 5/8" front bar and a 3/16" rear bar. I have a 1" front bar and an adjustable 3/4" rear bar on it now. These are parts from Quickor, back when they were noted for their sway bars

For the current suspension design to work, I think I need to get a shorter strut insert, cut down the length of the strut housing, and add a spacer to put between the track arm and the strut, so I can get a down and out angle rather than the current up and out angle. May need to hear from friend Falcon64 from Oz on this. I certainly need different springs, as the current springs have me on the bump stops

Quote:

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Originally Posted by mikedc

A 225 tire doesn't seem very narrow for a car that small. Between that and the larger rim diameter, I can see why the weak camber gain is bugging you.

BTW, do you know what the front roll center height is? If it's really low then that will magnify the body leaning problems. (Too high brings a different set of problems.)

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Do not know FRCH. I believe, based on my memory of angle of the track arms, it's somewhere near the center of the earth, so a big moment arm- except i'm on the bump stops, so it's only loading the tire


As previously indicated, I'm pretty willing to stay with the struts front end- If I can get it to work for me

Quote:

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I guess my focus on the camber gain issue is due to the short track arm length- IIRC it's about 9", I think many of the 'hot cars' are about 50% longer than that. The short length causes more transverse displacement of the bottom of the strut, adding more positive camber in compression than a longer arm adds. Hence the need for more static camber and it's woes

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Simpler FRCH question - where are the lower control arms at ride height? Parallel to the ground? A few degrees slanted one way or the other? It sounds like raising that front RC would pay off.

9-inch lower arms is pretty damn short. That makes the geometry's weaknesses more of a PITA because you get farther into them.

Is this a solid rear axle car?


Falcon64 said this about the front RC. It sounds like the voice of experience:

Quote:

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For rollcenter improvement, move the lower arm inner pickup point up half inch (this is max without cutting the rail).

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Of course if you move the lower arms then it will be goofing with the steering's bump steer. The short answer is you want to raise the steering rack up by the same amount that you raise up the inner arm pivots.

Some guys also raise RCs by lowering the outer end of the lower arm. IIRC that's usually done with aftermarket ball joints on the control arm (and tie rod?) I don't know what the options are for your chassis.

Quote:

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Have not driven w/ modern shocks- part of the issue is parts availability. For instance, Rock Auto (not that Rock Auto is the be all and end all) doesn't list any replacement front strut inserts or cartridges. I'm running a set of Bilstein sport inserts from 1980 (about 23K miles on them) and I believe I've probably damaged them, based on road feel.

The car came with a 5/8" front bar and a 3/16" rear bar. I have a 1" front bar and an adjustable 3/4" rear bar on it now. These are parts from Quickor, back when they were noted for their sway bars

For the current suspension design to work, I think I need to get a shorter strut insert, cut down the length of the strut housing, and add a spacer to put between the track arm and the strut, so I can get a down and out angle rather than the current up and out angle. May need to hear from friend Falcon64 from Oz on this. I certainly need different springs, as the current springs have me on the bump stops

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A new set of corner springs/shocks is a lot cheaper and easier than a Mustang 2 front end conversion. A roll-center change probably costs more labor than money. And you've already got improved sway bars for both ends. I vote to try re-habbing the stock front end and see how it turns out.

Look at it this way - if parts for that car are so hard to get in North America, then fresh struts might even be resellable if you decide to go M2 in the end.

Quote:

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Originally Posted by mikedc

Simpler FRCH question - where are the lower control arms at ride height? Parallel to the ground? A few degrees slanted one way or the other? It sounds like raising that front RC would pay off.

9-inch lower arms is pretty damn short. That makes the geometry's weaknesses more of a PITA because you get farther into them.

Is this a solid rear axle car?


Falcon64 said this about the front RC. It sounds like the voice of experience:

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At current ride height, the ball joint (outer pivot of the track arm) is at roughly the same height as the inner pivot, so FRCH will be just above ground level static and go underground in compression.

Went out and rough measured- inner pivot to ball joint pivot center is just about 9.5"

Solid axle rear

Agree w/ yhe Falcon

Quote:

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Originally Posted by mikedc

Of course if you move the lower arms then it will be goofing with the steering's bump steer. The short answer is you want to raise the steering rack up by the same amount that you raise up the inner arm pivots.

Some guys also raise RCs by lowering the outer end of the lower arm. IIRC that's usually done with aftermarket ball joints on the control arm (and tie rod?) I don't know what the options are for your chassis.

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Track arms are forgings,w/ integrated ball joints, generally ball joints are not considered serviceable, Never cut one up to see how it could be removed and replaced. There are aftermarket modified track arms for camber adjustment

Attachment 178356 Attachment 178357
putted around designing a spacer between the bakk joint and track arm.

moving the rack would not pose significant issues

Quote:

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Originally Posted by mikedc

A new set of corner springs/shocks is a lot cheaper and easier than a Mustang 2 front end conversion. A roll-center change probably costs more labor than money. And you've already got improved sway bars for both ends. I vote to try re-habbing the stock front end and see how it turns out.

Look at it this way - if parts for that car are so hard to get in North America, then fresh struts might even be resellable if you decide to go M2 in the end.

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I did find a set of Konis, 86 1835Sport that would work. They're listed as 'Reasonable Ride' in the description. Could probably be into inserts & coilover struts for maybe $500-600

Greg......images are attached. Still digesting mikedc and your posts from yesterday. ...will get back in an hour or so with any earth shattering revelations.

Attachment 178358Attachment 178359Attachment 178360

Front RC height is near ground level . . . solid axle rear . . .

What's the rear suspension on this thing? Leaf springs? I'm thinking about where the rear RC height is.

If that axle is on leaf springs then you should have a pretty tall rear RC. Like at/above the center of the rear wheels. That means the car has a pretty steep overall roll axis. Raising the front RC a few inches would be a plus IMO. Give the corner struts some more leverage to control that body roll. Get the front & rear RCs closer together.

Greg....
The Capri I'm referring to has been engine swapped, prepped and painted but not assembled yet.
That limits much more detail that i can put in text......hard to compare different settings etc.
BUT.....
- Rob's ride height has been established with current model Mustang GT alloy wheels (Torque Thrust D ripoffs).
- geometry has been put thru CAD package.
- Rob will use poly bushings and donuts on the sway bar. I
would put a rod end or clevis in place of the donut joint.
- being a strut car owner you will be more than aware of the
limited backspacing/sidewall issue. Need to use the smallest
dia spring.
- get rid of the rear bar.
- subject to ride height.....move the lower arm inner point up as much as the subframe will take. Lower arm should be slightly downhill at the wheel. Rob has half-assed this aspect and says he will do it after assembly.
- bump steer it before moving the rack (don't assume half inch up with arm equals half inch up for rack) that era of production was compromised by corporate constraints just like u said....carry-over Cortina parts.

Have u researched Cologne Capri or South Africa Perana geometry?

BTW....Calsonic recently closed down a plant here in Melbourne. I guess they were supplying Toyota who stopped production in Oz.
Have u worked with Alan Robins, purchasing/tech guy from Air International? ..a long time friend.

This is a free calculator for front-view suspension geometry. It's pretty quick & easy to use. It starts off in control arms mode but you can switch it to mac struts in the 'frame' settings.

http://vsusp.com

Quote:

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Originally Posted by mikedc

Front RC height is near ground level . . . solid axle rear . . .

What's the rear suspension on this thing? Leaf springs? I'm thinking about where the rear RC height is.

If that axle is on leaf springs then you should have a pretty tall rear RC. Like at/above the center of the rear wheels. That means the car has a pretty steep overall roll axis. Raising the front RC a few inches would be a plus IMO. Give the corner struts some more leverage to control that body roll. Get the front & rear RCs closer together.

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Currently leafs

Building a torque arm rear based on the Mustang Performance Handling book by Mathias. I can put a panhard on and control RRCH a little better