K Frame Differences...in general. Let's air this out :)

[Subliminal]

Ok guys, I propose a thread. Partially because I need some info, and partially because it would be nice to see a thread that just talked about the different k frames specific to our turbo dodges.

For example:

I've got the opportunity to grab an 87 Shelby Z k frame. Now my 86 GTS front suspension needs some work. Would it behoove me in any way to grab that 87 suspension to stick in the 86 GTS, or would it not be any better or even possibly worse?

What years are the most desirable years?

What are the differences between each?

What are the pros and cons of each?

Would this make a good compiled FAQ in the end?

Is there already a FAQ about this that I just don't know exists at the moment?

Am I an idiot?

Inquiring minds want to know.

:banaride:

[Lee'sdaytona]

Ok guys, I propose a thread. Partially because I need some info, and partially because it would be nice to see a thread that just talked about the different k frames specific to our turbo dodges.

For example:

I've got the opportunity to grab an 87 Shelby Z k frame. Now my 86 GTS front suspension needs some work. Would it behoove me in any way to grab that 87 suspension to stick in the 86 GTS, or would it not be any better or even possibly worse?

What years are the most desirable years?

What are the differences between each?

What are the pros and cons of each?

Would this make a good compiled FAQ in the end?

Is there already a FAQ about this that I just don't know exists at the moment?

Am I an idiot?

Inquiring minds want to know.

:banaride:
Well Said Damon! I feel your pain. I have another thread going about swapping in a K frame from an 89-90 daytona to my 87 daytona....some dufis snapped off the bolts that hold one of the sway bar brackets and just welded the bracket back on rather than fixing it right. Now I need to replace bushings...and I want it done right this time....
-Lee

[afsautoworx]

Id say fix your 86 front end unless its bent. I think the 87 front end still has the stub-bolt control arm which doesnt allow the controls arms to move up and down freely. The newer 89 shelby daytona front end is the one i think u want. It has the dual hinge "stamped steel" control arms which are better performance/ride wise. If u wanted to go farther the minivans with the dual hinge arms have stronger lower control arms, but weigh more. Id stick with the lighter ones. I would like to see a sticky about k-frame swaps/sway bar specs for all years. If i could help at all with research id be more than glad too.

P.s-youre not an idiot :)

[Bardo]

ok my question is are all k-frame the same ( dont mind me this post is drunk but i think i will under stand it in the morning)

[iTurbo]

K-based FWD Dodge vehicles

'84-'88 has the stub/strut configuration. Due to this design, the rear (stub) bushing doesn't pivot like the front bushing which somewhat hinders it's up/down movement. The control arms are stamped steel. You can upgrade your '84-'88 control arms by getting control arms from an '84-'88 Caravan/Voyager. They are identical but are boxed/gusseted for more strength. I have the Caravan control arms on my Omni so this will work for you L-body guys too.

'89-'90 Much improved design over the previous K-frame. Control arms were still stamped but featured dual pivot bushings on the front and rear.

'91+ Essentially the same as the previous design but the control arms are cast and look nearly indestructable compared to stamped arms.

Polyurethane bushings are available for any style K-frame/control arms from polybushings.com

[afsautoworx]

ok my question is are all k-frame the same ( dont mind me this post is drunk but i think i will under stand it in the morning)

well u cant put an l-body k-frame into a minivan

[turbovanman²]

You can use up to 90 for the Minivan control arms in earlier car models-Mini's are braced so there stronger. Stamped arms are lighter.

Cast arms are heavier, much heavier.


K-members-

L bodies are unique to themselves
The rest of the car line you can mix and match but be sure to use the apropiate knuckles with each year.
Minivans are unique to themselves.

[Subliminal]

So, would that 87 Shelby Z k frame be identical to my 86 frame, with the exception of maybe the sway bar? Will the knuckles from my 86 bolt right into the 87?

Thanks!

[afsautoworx]

/\ Yes they should be the same, knuckles should interchange no problem, and yes the swaybar i think is 1/16" bigger on the 87 Z

[rbryant]

So there are 5-6 basic frames:

1) 84-88 K based frames (back bushing is a stub)
2) 89+ K based Frames (dual pivot)
3) 84-88 Van Frames (like the car but wider version)
4) 89+ Van frames (like the car but wider version)
5) Lbody frames (older ones might different and weaker) 1.5" narrower and the passenger front mount is 1" closer to the center.
6)? 81-83 K car? (Aries Reliant, etc) Is this the same as the 84-88 Kcar?


Newer dual pivot arms require newer spindles.

Does anyone have the weight on a cast arm vs/ stamped arm? I know a guy that drilled a bunch of holes in the cast arm to help remove weight.

-Rich

[GLHNSLHT2]

84's to 88 also differ depending on what sway bar you got. If you got the big bars they have a standard poly style bushing with the upper brackets welded in and a 5spd mount wether you got the Auto or the 5spd. They're probably a bit beefier with the brackets welded on. It would only Benifit SUB if he didn't have the big bars to go to the 87 k he has. If I were him and contimplating this I would make the jump to a 89/90 unit with stamped arms. Then he just has to drill out the rack mounting bosses a bit and bolt it all in. Then the big bar from 86-90 bolts in with the right bushings. and he get's the benifits of the dual pivots. Going from an 87 K with poly LCA bushings to a 90 K with poly bushings dropped the ride height of my 87 Z by 1/2" because the pivots move so much easier it allowed more weight to be placed on the eibachs. The ride is as smooth with the koni's on full stiff with the new k as it was on full soft with the old kmember. The car actually feels more solid as well because of the extra beefiness of the newer K and the fact that the LCA's aren't twisting the k as they move like they do in the old style kmember. The newer K's are so much nice if you can upgrade to them. Using the 89-90 Stamped arms offer lighter weight, the ability to use your current spindles/knuckles, and some crash protection if you hit a curb, better to bend a LCa than the kmember/frame.

[CSX321]

Newer dual pivot arms require newer spindles.
Why? I've been using a '93 cast iron dual-pivot frame and arms on my '87 CSX for years. I never noticed a problem.

[Directconnection]

Why? I've been using a '93 cast iron dual-pivot frame and arms on my '87 CSX for years. I never noticed a problem.

The geometries will not work as hand in hand as if you used the cast arms with the designed knuckles. It's all about ball joint positioning and roll centers. It will work, but like I said.... not optimal.

[iTurbo]

For a while I had '91 knuckles and brakes from a GTC on my Shelby Lancer, which still had the original K-frame and control arms at the time. The only wierd thing I noticed was the knuckle sat up high off the ball joint. This made for about 1/2" gap between the bottom of the knuckle and control arm. Never noticed anything wrong driving it that way though. I've since upgraded to all '91 front suspension and the gap issue is gone.

[BadAssPerformance]

The geometries will not work as hand in hand as if you used the cast arms with the designed knuckles. It's all about ball joint positioning and roll centers. It will work, but like I said.... not optimal.

What dimensions change with the '91+ cast arms and '89 knuckles?

[afsautoworx]

Caster i believe, but it will be equal on both side. Moves wheels ahead 1/2"

[BadAssPerformance]

is that a bad thing? if so, why?

[rbryant]

New knuckles on the old K frame is bad for caster. I think it would probably bring you back to about .5 or even 0 degrees.

Old knuckles on a new frame might be ok because it would actually increase caster. Increased caster is good for straight ahead traction and better camber when cornering. Of cource if you are rubbing the fenders that is a problem...

If it moves it ahead .5" then on my car it would get about 1.4 degrees more positive caster. This can be calculated with the following formula:

caster change = arctan(hm/sh)

where

hm = hub movement (forward will give the amount caster is increased in caster backward is amount decreased)

and

sh = height from wheel center to strut top

So if you have a stock caster angle of around 1 degree on a stock old frame we can figure some things out if we have before and after measurements for each setup.

-Rich

[BadAssPerformance]

Good info!

[Directconnection]

What dimensions change with the '91+ cast arms and '89 knuckles?


Man, you had to ask:confused: I forget the specifics as I looked into the differences a couple years back for one of my cars (that is still not finished btw)

The control arm to knuckle positioning of the balljoint is very different. The cast arms offer a totally different ball joint location which improves the roll center greatly. The knuckles accomodate this change as well. If you were to put both side by side... stamped arms with '89-90 style knuckles alongside cast arms with R/T knuckles I have, you will see how the knuckles were re-designed quite a bit where the positioning of the ball joint and center of the hub distance is. They work hand in hand in improving the roll center...but can't have it w/out one or the other.

Sorry if I don't have actual measurements to support this... it's like 10 degrees out in my garage to go verify again.

[turbovanman²]

Man, you had to ask:confused: I forget the specifics as I looked into the differences a couple years back for one of my cars (that is still not finished btw)

The control arm to knuckle positioning of the balljoint is very different. The cast arms offer a totally different ball joint location which improves the roll center greatly. The knuckles accomodate this change as well. If you were to put both side by side... stamped arms with '89-90 style knuckles alongside cast arms with R/T knuckles I have, you will see how the knuckles were re-designed quite a bit where the positioning of the ball joint and center of the hub distance is. They work hand in hand in improving the roll center...but can't have it w/out one or the other.

Sorry if I don't have actual measurements to support this... it's like 10 degrees out in my garage to go verify again.


Exactly, if you use the older knuckles on cast control arms, it moves the control arm up and out aprox 1/2-1 inch.
I don't know why but on vans, when you try this, the inner cv joints blow out but on the cars, it doesn't????????????

[CSX321]

Old knuckles on a new frame might be ok because it would actually increase caster. Increased caster is good for straight ahead traction and better camber when cornering.
Ah, okay. That's the setup I have. I did the same swap on my old '88 Sundance, and I always felt the later frame with cast arms improved the ride.

[BadAssPerformance]

So, how much do the cast LCA's weigh vs. the '89 stamped LCA's?

[Turbodave]

Working on an FAQ for this one right now.

[Directconnection]

So, how much do the cast LCA's weigh vs. the '89 stamped LCA's?

I measured them a while back on an old bathroom scale and noticed only like 1-2 more pounds with the cast arms....

[BadAssPerformance]

cool.

[Stinkbox]

i recently smashed into a curb when hydroplaning in my 90 shelby and ruined one of pumpers:( and bent my inner tie rod and my control arm. i used to look at the earlier non cast arms and think man those look super weak, i can't believe they are 2 pieces but im glad i had them that day as it bent up pretty good and i bet the cast wouldn't have. i also put in a manual tranny k member since i swapped to a manual like a yr and a half ago and had no bobble strut lol. but the 89+ k members are all identical. 89-90 control arms are the same and 91+ stamped arms are the same. so you could put any 89+ control arms on your 89+ k member just make sure you have the right steering knuckles. don't know about vans though. excluding l bodies too.

[turbovanman²]

. don't know about vans though.

See my earlier post on vans, :nod:

[rbryant]

We should get the exact dimensions for each setup.

People would have to take some measurements... and it would probably have to be on different cars. It will be touchy... Perhaps the distance from center of front wheel to center of back wheel is sufficient. That also depends on the ride heights though.

Someone with a couple hours to kill at the junkyard could do this on a car but it would be a PITA.

I assume that the stock setting for older cars is about a degree of positive caster. (someone should look this up)

Based on my figures below we should see if my calculated new caster angle matches the spec on the newer cars (someone should look this up). If so things should be accurate.

If someone can give me the old and new specs for a daytona I can probably figure out how much things really move and fix all of the equations if needed.

That means:


Assumptions:

The length from strut top to wheel center is somewhere between 18 and 22 inches.

Newer control arms move the ball joint forward about an inch.

Newer hubs move the hub center back .5"



The full 91+ setup is:

About .5" forward: 1.3 to 1.6 degress more positive caster. (a good thing)


The new kframe with old knuckles is:

About 1" forward: 2.6 to 3.2 degress more positive caster. (starting to get extreme but not that far beyond what new nissans come with)


The old frame with new knuckles is:

About .5" backward: 1.3-1.6 degrees less positive caster. (This might actually lead to overall negative caster which isn't desireable.)

Now someone look things up and/or measure and see how close I am. :)

[turbovanman²]

Also, using old knuckles with new cast arms and K-member moves the knuckle outward aprox 1/2-1 inch.

[Directconnection]

Also, using old knuckles with new cast arms and K-member moves the knuckle outward aprox 1/2-1 inch.


....and more importantly.... positions the knuckle differently. This gives the control arms a bad angle for roll center and can induce bump steer as well. Chris Stills would be the more knowledgeable person to ask about this.


This weekend, I will try and measure balljoinmt positioning to control arm.

[csracer]

I went through this a year or so ago with my car. I had a 91+ kframe/knuckles/cast arms and my stock 89 daytona shelby kframe/ knuckles/stamped dual pivot arms. I swapped all combinations of these parts. First thing i found is that, the entire 91+ setup increased the caster and moved the wheels forward approx 1/2" inch (which has already been noted in this post). This would not work on my car because of the tire would hit the 89 shelby air dam where it wraps areound the fender. next thing I tried was putting the 89 control arms in with the 91+ frame and knuckles, my caster was restored to normal for my 89 car. Then I put the 89 kframe in with the 89 arms while keeping the 91+ knuckle, nothing changed. This is setup I currently use. I like the 91+ knuckles becuase they have the bolt on adapter which will accommodate the future bigger brake upgrade, and more importantly the ball joint pickup is lower.

So, in summary I found the Kframe to be the same, the cast arms have more caster built into them than the stamped, i dont have a degree change for the caster but it moved the wheels forward 1/2". The 91+ knuckles have the ball joint pickup lower by 3/4" and helps keep the roll center acceptable when lowering by keeping the control arm closer to paralell to the ground. I did not find the 91+ knuckles to change caster or have any negative effect.

If there is something i missed about the knuckles that would change caster, let me know, because all my findings put the caster change solely in the 91+ control arms

[turbovanman²]

Awesome Chris, :thumb:

[Directconnection]

Awesome Chris, :thumb:

+1^^^

I was hoping he would chime in! Thanks Chris.

Chris... can you elaborate on the balljoint situation with the combination of a stamped arm with the '91+ knuckles? We talked at length about this a couple years back when I was piecing together the suspension upgrades for my project car. Chris went out of his way and personally snail mailed me an envelope with a photocopied article on the effects of roll center and the many other areas of suspension geometries. Thanks again!

[afsautoworx]

One question i have is the 91+ ball joint the same as the 89? Anyone?

[turbovanman²]

One question i have is the 91+ ball joint the same as the 89? Anyone?

Yep, same one. :nod:

[Lee'sdaytona]

Alright so I have a few questions:
It looks like I want to switch my 87 daytona's stock K frame over to the 89-90 frame. What all do I need from a donor car? Is the rack and pinion built into the frame? Last time I was under the car thats what it looked like. If so, that means I run the risk of grabbing a bad rack and pinion from a yard.
Someone mentioned about setting the camber and NOT RUNNING POSITIVE camber...I have no idea what this is. What tools are needed? Fancy puller sets? I have a nice toolbox of metric and standard: deep sockets, wrenches...have a new torque wrench on the way...breaker bar...but what other tools are needed? Would it need to be re-aligned after the swap?
Do I have to mess with the C/V joints? I don't even have the tool to attach the metal straps that hold the boots on....
any advice would be great.
thanks,
Lee

[afsautoworx]

Ok. The 89 shelby daytona frame is what u want. The rack and pinion is BOLTED onto the K-frame, then the K-frame is BOLTED onto the frame. If u do pull a k-frame from a junkyard car yes u do run the chance of a bad rack but u can buy a new one if and when that happens. Setting the camber is something u do after u get the kframe in. Positive camber is when the top of the wheel tilts outwards, Negative camber is when the wheel tilts inward. When u get the car aligned just ask them for a little bit of negative camber, prob 1 degree. Pulling the crossmember out isnt that bad. Unbolt the ball joints on each side, disconnect power steering lines, disconnect steering shaft coupler (1 bolt), disconnect bobble strut. Then theres 4 bolts that hold the crossmember to the frame, take them out and it should come right out. You shouldnt have to mess with cv joints and yes u should have it re-aligned after. The tools u have should be alright, breaker bar is prob a good idea for the rack to frame bolts. anymore questions? :)

[afsautoworx]

IF ANYONE IS DOING A K-FRAME SWAP
thought id add this so no one makes this mistake. Before u take out the old crossmember out of your car make sure the steering wheel is centered(wheels straight ahead) Next, when u put the new crossmember in, if youre using your old rack and pinion swapped onto new crossmember or new rack and pinion, etc. make sure that is centered too. You can eyeball it (equal length on both inner tie rod bellows) or u can turn it lock to lock by hand and get it centered that way. Now when u put it all back together the steering wheel isnt way off when youre driving straight, and youll be able to turn left too! Hope i covered everything

[csracer]

One question i have is the 91+ ball joint the same as the 89? Anyone?


They are different part numbers and wont interchange between the arms, but the ball joint's stud height and diameter are the same so they will fit into either of the knuckles.

[csracer]

+1^^^

I was hoping he would chime in! Thanks Chris.

Chris... can you elaborate on the balljoint situation with the combination of a stamped arm with the '91+ knuckles? We talked at length about this a couple years back when I was piecing together the suspension upgrades for my project car. Chris went out of his way and personally snail mailed me an envelope with a photocopied article on the effects of roll center and the many other areas of suspension geometries. Thanks again!


I will try and write up a explanation about roll centers, ride height and control arm angle later today or tomorrow, gotta run right now

[Lee'sdaytona]

Ok. The 89 shelby daytona frame is what u want. The rack and pinion is BOLTED onto the K-frame, then the K-frame is BOLTED onto the frame. If u do pull a k-frame from a junkyard car yes u do run the chance of a bad rack but u can buy a new one if and when that happens. Setting the camber is something u do after u get the kframe in. Positive camber is when the top of the wheel tilts outwards, Negative camber is when the wheel tilts inward. When u get the car aligned just ask them for a little bit of negative camber, prob 1 degree. Pulling the crossmember out isnt that bad. Unbolt the ball joints on each side, disconnect power steering lines, disconnect steering shaft coupler (1 bolt), disconnect bobble strut. Then theres 4 bolts that hold the crossmember to the frame, take them out and it should come right out. You shouldnt have to mess with cv joints and yes u should have it re-aligned after. The tools u have should be alright, breaker bar is prob a good idea for the rack to frame bolts. anymore questions? :)
Yeah that clears up a lot for me, thanks! So, it sounds easiest to keep the rack and pinion that comes with the replacement K frame so I don't have to worry about alignment. In this case, I should make sure both the donor car as well as my car has the steering wheel straight when I go to remove them correct? Alright well its not too often that I see a SHELBY daytona come through the yards. But 89 5-spds are more common....and I assume the SHELBY is the better frame. Hopefully the closer I get to spring, someone in my area will have one to sell (Either in my college town, Lancaster, PA or my hometown, Ewing (trenton) New Jersey.)
thanks again,
Lee

[Subliminal]

Lee,

I don't think it matters if it's a Shelby or not. an 89 K Frame should be an 89 K Frame, as long as it isn't from a minivan or an L body.

As far as the alignment, he was talking about the alignment of your steering wheel. You want the wheel in the correct position or it looks funny. You almost always need an alignment when you do something like this, regardless.

I don't think you should wear yourself out searching for a shelby setup. Just look for the year.

[Lee'sdaytona]

Lee,

I don't think it matters if it's a Shelby or not. an 89 K Frame should be an 89 K Frame, as long as it isn't from a minivan or an L body.

As far as the alignment, he was talking about the alignment of your steering wheel. You want the wheel in the correct position or it looks funny. You almost always need an alignment when you do something like this, regardless.

I don't think you should wear yourself out searching for a shelby setup. Just look for the year.
Alright thanks Damon....I had a feeling it didn't matter, but he said 89 shelby daytona so I wanted to make sure.
-Lee

[afsautoworx]

The 89 frames are not the same. I had a 89 Daytona 2.5 5spd non-turbo that had the old stub strut k-frame. I think the shelby is the difference.


They are different part numbers and wont interchange between the arms, but the ball joint's stud height and diameter are the same so they will fit into either of the knuckles

Thats good to know, didnt know if the ball joint stud height was different which would affect roll/moment center too.

I forgot to add too, in my writeup about taking the kframe out, you need to disconnect the tie rods from the knuckles too.

[Lee'sdaytona]

The 89 frames are not the same. I had a 89 Daytona 2.5 5spd non-turbo that had the old stub strut k-frame. I think the shelby is the difference.



Thats good to know, didnt know if the ball joint stud height was different which would affect roll/moment center too.

I forgot to add too, in my writeup about taking the kframe out, you need to disconnect the tie rods from the knuckles too.
hmmm....interesting....
-Lee

[Directconnection]

The 89 frames are not the same. I had a 89 Daytona 2.5 5spd non-turbo that had the old stub strut k-frame. I think the shelby is the difference.



Shouldn't be any difference. Maybe that '89 was really an '88 as there were 2.5 motors in '88 as well...but not the common block 2.5's. Or...someone messed up the front end and swapped in an entire k-fram assembly from a donor car?

[afsautoworx]

it was a CB....no fuel plate. Might of been a leftover 88 front end. Stranger things have happened. Might of been a donor. im goin with leftover front end. Had solid rear rotors on it too!

[Directconnection]

How's your project coming along Rob? That Shadow is still available...the person interested wanted a turnkey car that'll run 12's for $2,000 I guess:yuck:

[afsautoworx]

the person interested wanted a turnkey car that'll run 12's for $2,000 I guess
wow...do u know where i can buy one of those? :) honestly tho, that shadow should run 13 sumthin shouldnt it. I havent done much to the daytona, just been gathering parts. I didnt make it over to brents house...didnt wake up till 12 and the race started at like 1:30 so i didnt bother. What have u been up too lately?

[TylerEss]

Ok, so is the V6 K-Frame the same as the 4-cylinder one?

Can we swipe K-Frames out of V6 Daytona ESes?

Those of us who want to keep old-style knuckles and still get dual-pivot A-Arms need to find 89 or 90 cars, and there's lots of V6es looking to get chopped up. :nod:

[Directconnection]

wow...do u know where i can buy one of those? :) honestly tho, that shadow should run 13 sumthin shouldnt it. I havent done much to the daytona, just been gathering parts. I didnt make it over to brents house...didnt wake up till 12 and the race started at like 1:30 so i didnt bother. What have u been up too lately?

It's basically the same setup that someone I know managed high 11's with in a Shadow. With a 3-bar cal, it will be a solid 12 second car (low 8's in the 1/8th for us folk;-) with the work/parts that it has.

[turbovanman²]

Ok, so is the V6 K-Frame the same as the 4-cylinder one?

Can we swipe K-Frames out of V6 Daytona ESes?

Those of us who want to keep old-style knuckles and still get dual-pivot A-Arms need to find 89 or 90 cars, and there's lots of V6es looking to get chopped up. :nod:


Yes, sheesh, :eyebrows: :p

[TylerEss]

Thanks, Simon. :lol:

[turbovanman²]

Thanks, Simon. :lol:

To quote Red Dwarf-there all the same Dave, wheres the 4 banger? there all the same Dave, wheres the V6? there all the same Dave, :p

[CSX321]

To quote Red Dwarf-there all the same Dave, wheres the 4 banger? there all the same Dave, wheres the V6? there all the same Dave, :p
I love Red Dwarf! Haven't been able to see it since I moved from Dallas last year, though. No stations I can get are showing it.

[turbovanman²]

I love Red Dwarf! Haven't been able to see it since I moved from Dallas last year, though. No stations I can get are showing it.


You can buy it on DVD, I have seasons 1-4 right now. Also, Seattles KCPQ started running again, every sun night at midnight to 1 am. I finally get to see how they found Kryton, :thumb:

[rbryant]

I measured them a while back on an old bathroom scale and noticed only like 1-2 more pounds with the cast arms....

Are the 89 spindles also lighter? I would think so because the single piece shouldn't need as much metal (and no bolts) when compared to the spindles with the bolt on brackets.

-Rich