Dual Pivot K-Frame on '87 CSX

[GLHNSLHT2]

Grrr. So even a stamped set will move my wheels forward? How bad?

Force Fed is the only one I've ever seen say that. When I did the swap on my 87 Tona I didn't notice any movement in the wheel wells. Looking at the stub strut vs stamped dual pivot it looks like the same arm just has a different rear pivot.

[cordes]

Force Fed is the only one I've ever seen say that. When I did the swap on my 87 Tona I didn't notice any movement in the wheel wells. Looking at the stub strut vs stamped dual pivot it looks like the same arm just has a different rear pivot.

Simon has been known to claim movement from a knuckle only switch. All of Rich's work would indicate that it is only the cast vs. stamped arms which cause a change in wheelbase.

[Joe Anderson]

Would the caster be off for using a 1989 swing-arm crossmember into a 87,without changing the spindals ?

Or is the caster factor only for switching crossmembers later than 1991 ?

[turbovanman²]

Simon has been known to claim movement from a knuckle only switch. All of Rich's work would indicate that it is only the cast vs. stamped arms which cause a change in wheelbase.

I am only going on what others told us years ago. Rich has since done some homework on this. We both agree that the ball joint pad is lower on the cast knuckles and will alter ride height a bit and I found out that if you use cast knuckles on stamped strut control arms, it moves the knuckle out in up and down travel.

[Force Fed Mopar]

Just remembered, I put a dual-pivot frame w/ stamped arms into chilort's '86 Turbo Z CS using his original knuckles. I'll take a pic of it tomorrow since it's at my shop, but there's no drivetrain in it so it's sitting a little high in the front.

I put a cast setup in my '87 Shelby Z, put 205/60/16's on the front and it rubbed the front corner of the wheel well when I turned pretty bad. Put stamped arms because everyone said they put the wheel in the same place as the 88-older stub strut arms, guess what? Still rubbed bad, didn't move them back at all. Had to go back to 205/55/16's in the front.

[ShelGame]

Running 24.5" slicks on the front of my Daytona, the tires rub the front of the lower bumper really bad when turning. Looking at the side view of the car, you can tell the tires are about 3/4" forward in the wheel wells. Every pic of a Daytona I could find looked exactly the same. Only seems to be an issue with larger tires. This winter, I plan to put spherical bearings at the pivots and move the control arms back 1/2" in the process...

[rbryant]

You do not have to change knuckles to use the dual pivot arms. And your wheels will get moved moved forward regardless of which style you use. Stamped can use the original swaybar, if you go cast you will need a cast-style swaybar.

Do you have measurements to support the wheels moving forward with the stamped dual pivot arms vs the older stamped arms? I didn't see that happen and others have confirmed that the change is in the cast arms only.

What I did see was a set of cast arms that were purposely machined to the front side of the ball joint boss from the factory. They seem to have added the caster as an afterthought. That means that depending on how the cast arms were machined they might or might not have the extra caster.

The ball joints were only about 10mm forward on the cast arms that I compared with the dual pivot stamped arms.

The only downside to mixing and matching knuckles and arms is that the steering stops on the cast arm/new 91+ knuckle won't be there with other combos. The 91+ knuckles do push the ball joint downward which is a good thing for the geometry.

-Rich

---------- Post added at 01:00 PM ---------- Previous post was at 12:54 PM ----------

I found out that if you use cast knuckles on stamped strut control arms, it moves the knuckle out in up and down travel.

No, that is incorrect you didn't figure out that it moved your knuckle out.... You thought that and then it was researched and found to be incorrect info.
You are going to really drive me nuts on this for the ~4th time aren't you?

We went over this in detail more than once and I can probably even find you finally admitted it in a post... What you had was the wrong equal length axle (from a car on a van) which created your problem of making the axle assembly too short.

Moving the ball joint pad downward does VERY VERY little to the axle length. The math proves it and additionally they never changed the axle lengths for any of the Kcars and therefore that means what you are saying can't possibly be true.

The only real thing that happens is the ball joint pushes the control arm downward and then will also put more pressure on the swaybar. The axle length doesn't change significantly through the control arm up/down travel (or a McPherson suspension just wouldn't work).

-Rich

[turbovanman²]

No, that is incorrect you didn't figure out that it moved your knuckle out.... You thought that and then it was researched and found to be incorrect info.
You are going to really drive me nuts on this for the ~4th time aren't you?

We went over this in detail more than once and I can probably even find you finally admitted it in a post... What you had was the wrong equal length axle (from a car on a van) which created your problem of making the axle assembly too short.

Moving the ball joint pad downward does VERY VERY little to the axle length. The math proves it and additionally they never changed the axle lengths for any of the Kcars and therefore that means what you are saying can't possibly be true.

The only real thing that happens is the ball joint pushes the control arm downward and then will also put more pressure on the swaybar. The axle length doesn't change significantly through the control arm up/down travel (or a McPherson suspension just wouldn't work).

-Rich

Yes, I admitted I have the wrong intermediate shaft in, but with the correct combo of suspension pieces-IE cast control arms, matching knuckles and K-member, I am still using those axles, have been since I did the swap around 2008, so if the knuckle isn't moved out, explain how when I put cast knuckles on stamped strut style control arms the inner joint came apart due to the axle being over extended? but with the correct combo, its all good?

[RoadWarrior222]

because van not car

[rbryant]

Yes, I admitted I have the wrong intermediate shaft in, but with the correct combo of suspension pieces-IE cast control arms, matching knuckles and K-member, I am still using those axles, have been since I did the swap around 2008, so if the knuckle isn't moved out, explain how when I put cast knuckles on stamped strut style control arms the inner joint came apart due to the axle being over extended? but with the correct combo, its all good?

I don't know, bad axle?

The intermediate changes everything. It is shorter making both sides off when you center the engine. Are you still running the wrong intermediate? If so it is all a crapshoot with the wrong axle lengths.

I know for sure that the ball joint doesn't move outward or inward on the stamped vs dual pivot arms:

Traced overlay of cast vs. stamped control arms aligned.


The center of the ball joint does move forward a bit but it is less than half an inch.

Unfortunately an overlay of the old style control arm on this drawing wouldn't have been straight forward or obviously correct.

If what you are saying is true (that the 91+ knuckles are not compatible with 88 and older control arms) then based on the above overlay trace where the ball joints are clearly not moved outward: the early 89/90 knuckles would also not be compatible with the 88 and older control arms.

Are you also saying that the 89 knuckles would have this problem?

-Rich

[Force Fed Mopar]

No measurements, all I know is, the wheels didn't move when changing from cast to stamped and back again. Maybe not all cast arms have the same ball joint location?

What if I measure from the rear k-frame stud to the center of the balljoint? I can measure that on my '87 w/ cast arms and on chilort's '86 w/ stamped arms, if that will tell us anything.

I think Simon's problem was probably a short axle and improper engine/trans centering

[Frank]

Makes me second guess this k-frame change... maybe I will just put new bushings in.

[Force Fed Mopar]

As long as you aren't running 60 series on it, you should be fine

[Frank]

Ya, but I don't like the idea of my wheels looking off centered.

[cordes]

Makes me second guess this k-frame change... maybe I will just put new bushings in.

That's loser talk. Dual pivot or bust!

I guess I could take measurements of my two 86' E body cars. One with stock suspension and the other with a 94' Shadow front suspension to include everything from K frame to knuckles and brakes.

[Frank]

Not looser talk. Just want the car to look any more stupid then it already does, especially when I am in it.

[turbovanman²]

I don't know, bad axle?

The intermediate changes everything. It is shorter making both sides off when you center the engine. Are you still running the wrong intermediate? If so it is all a crapshoot with the wrong axle lengths.

I know for sure that the ball joint doesn't move outward or inward on the stamped vs dual pivot arms:

Traced overlay of cast vs. stamped control arms aligned.


The center of the ball joint does move forward a bit but it is less than half an inch.

Unfortunately an overlay of the old style control arm on this drawing wouldn't have been straight forward or obviously correct.

If what you are saying is true (that the 91+ knuckles are not compatible with 88 and older control arms) then based on the above overlay trace where the ball joints are clearly not moved outward: the early 89/90 knuckles would also not be compatible with the 88 and older control arms.

Are you also saying that the 89 knuckles would have this problem?

-Rich

Stock 89 everything except Polybushings, equal length setup, didn't know until recently but car intermediate shaft, van was fine for 2 years or so then wanted 11" brakes, PUT ON 91 cast knuckles, drive out of the shop and the left cv axle came apart, PUT back the 89 knuckle and no issues. 6 months later replace everything with 91+ suspension, running SAME axles and int shaft for what, 6-7 years? and ZERO issues. I figure it moved the axle 2" when it came apart. I'll take pics of how much the axle sits inside the inner cv joint next time its in the air.

We already know this about the ball joint pad but it was a bugger to get the control arm hooked up with the cast knuckle and stock control arm.

I think Simon's problem was probably a short axle and improper engine/trans centering

See above.

---------- Post added at 11:53 AM ---------- Previous post was at 11:51 AM ----------

Not looser talk. Just want the car to look any more stupid then it already does, especially when I am in it.

That's going to be a tall feat,

[csxtra]

Frank,

Another datapoint for you...

I did a dual-pivot k-frame swap to my CSX over the winter as part of my complete suspension redo, and I went with the stamped arms and the wheel did not move forward at all.

Aside from enlarging the mounting holes in the steering rack it is a pretty easy swap. The hardest part was getting the old rusty bolts out of the pivots so I could put in Johnny's poly bushings.

However, I did go with the later knuckles because I lowered the car with Rich's BC racing coilovers and I wanted the balljoint position to be lower to prevent the arms from pointing up when lowered. You don't need to do this unless you are planning on lowering the car, just bolt in the k-frame, hook your existing knuckles onto the ball joints, get it aligned, and enjoy!

I looked into the 11" brakes, but the calipers will hit on Centurion IIs, so I went with the 10.26" stock size rotors and bolted 2nd-Gen intrepid calipers onto the factory brackets and now I have TONS of easily-available options for brake pads, and I can lock up all 4 wheels whenever I want...would 11" brakes be better? Yes, but I want to keep the stock wheels...numbered car and all.

The car rides MUCH nicer than it did before, even with a much higher spring rate, and the handling is greatly improved.

I hope this helps,

Warren

[rbryant]

Not looser talk. Just want the car to look any more stupid then it already does, especially when I am in it.

If you find a set of cast arms where the ball joint is machined in the center of the boss then the wheel movement should be negligible.

Notice in the picture below where the ball joint movement is because of where the hole was machined:



This is the control arm from the traced overlay that I previously posted and the offset is something like 10mm IIRC.

-Rich

[Force Fed Mopar]

Stock 89 everything except Polybushings, equal length setup, didn't know until recently but car intermediate shaft, van was fine for 2 years or so then wanted 11" brakes, PUT ON 91 cast knuckles, drive out of the shop and the left cv axle came apart, PUT back the 89 knuckle and no issues. 6 months later replace everything with 91+ suspension, running SAME axles and int shaft for what, 6-7 years? and ZERO issues. I figure it moved the axle 2" when it came apart. I'll take pics of how much the axle sits inside the inner cv joint next time its in the air.

We already know this about the ball joint pad but it was a bugger to get the control arm hooked up with the cast knuckle and stock control arm.



See above.

I switch from '87 spindles, arms, k-frame to 91-up spindles, arms and k-frame, used the same axles. Never had a problem.