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Rack and Peanut steering for A bodies research...commments?
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Author:  sandy in BC [ Mon Aug 20, 2007 7:14 pm ]
Post subject:  Rack and Peanut steering for A bodies research...commments?
When I was at Lous last month we had a lil discussion about converting Early A bodies to R+P steering. As I had converted my mudbogger to R+P last summer with great success I was very interested in what Lou(Dart 270) was thinkin on trying.

I told Lou I would do a lil research when I got home. It only took me a month to get a round tuit.

so....heres what I discovered:

Our cars have the steering linkage behind the K frame. Any swap that requires steering geometry for street or road racing apps must have the steering behind the K. It is very possible to mount the rack to the K and have the steering column/coupler line up.

The big grief revolves around how the Abody linkage works. The catch is the idlerarm/pitman arm setup. The rack would have to be narrow enough to replace the centre rod leaving the tie rods and idler arm(s) in their stock locations in order to have the Akerman Principle geometry work correctly.

As well a narrow rack that operates correctly in a behind the axle position; one would need to add a 2nd idler arm to replace the original steering box pitman arm. (perhaps an Aussie idler arm is the correct mirror image idler for this app) Dion R certainly would have some insights on mounting another idler.

The biggest obstacle is finding the narrow rack. I investigated the racks I have access to here and found only one that was close.....it would seem to be perfect for a late B Body...but certainly not an early A.

Comments and abuse welcome.......but dont even start about swapping spindles and putting the rack infront of the K.....dats just dumb.
Author:  dakight [ Mon Aug 20, 2007 7:28 pm ]
Post subject: 
This past spring I put a rack in my grandson's Toyota. The rack was mounted to the firewall, well behind the steering axis, and there were no idler arms. My 82 K-car was set up the same way as I recall so I'm not sure I understand the need for idler arms. Ackerman, as I understand it is determined by the angle of the steering arms, not by the idler and pitman arms. I don't see why the rack cannopt be attached directly to the steering arms, eliminating the stock linkage all together.
Author:  sandy in BC [ Mon Aug 20, 2007 7:52 pm ]
Post subject: 
Chrysler was so proud of its parallelogram (sp?) geometry......you dismiss it so quickly.

The linkage could be deleted for a drag only car.....but the design is so simple and elegant it would be a great loss to lose the advantages of the Parallelogram geometry just to change to a rack. The bump steer would drive you nutz.

The Toy and K car have a strut front suspension which has totally different geometry from an A arm suspension. My mudbogger with a solid axle is different again (and way easy)
Author:  argentina-slantsixer [ Mon Aug 20, 2007 8:03 pm ]
Post subject: 
why would put the arranging in front of the K be bad?
Author:  dakight [ Mon Aug 20, 2007 8:14 pm ]
Post subject: 
Dakotas starting in about 2003 have a rack and pinion married to a conventional unequal length control arm suspension. How did they do it? I looked for pictures but have not been able to find any.
Author:  SlantSixDan [ Mon Aug 20, 2007 8:22 pm ]
Post subject: 
There exist R&P conversions for A-bodies...in Australia, which means they're for RHD...although certain of the kits are listed as available for LHD or RHD. See for example here (I have no experience with this vendor) and here (these folks have a mixed reputation; proceed carefully) and I am/was fairly sure the very reputable Pentastar Parts & Restorations (Rayman440 on here) has something worth asking after.
Author:  sandy in BC [ Mon Aug 20, 2007 8:36 pm ]
Post subject: 
Our POS Dakota (1988) has R+P....in front of the axle.

Putting the rack in front of the axle requires swapping spindles from side to side and reversing them. It should be no surprise that the geometry is pretty wonky. This is what some drag racers seem to do....of course they only go in a straight line.....their interest is getting the steering out of the oil pan/header area.

These cars handle/steer too well to abandon their sensible geometry.
Author:  OzHemi [ Mon Aug 20, 2007 11:28 pm ]
Post subject: 
I have a Dodge City rack K frame in my Charger.. I got the bare K frame from him and added the rack and made the steering coupler. It was a terrific upgrade and I would do it again in a second.. He is great to deal with as well..been at it alot longer then alot of other newbie Valiant places around Oz now.
They can do the conversion K frame for other bodies as well.. a mate in Oz with a '68 Charger R/T (a 440 car getting a Hemi) has a power rack setup from Dodge City for it as well.

Just keep in mind, you have to notch the oil pan somewhat for a V-8 application, the Hemi-6 does not need it.. would just be a matter of finding a LHD rack with the same mounts. And making up the intermediate shaft of course as well.. the Aussie cars have the steering box further back then a LHD car, so the shaft would have to be abit longer is all.. (I used, and the kits use a shortened Commodore intermediate shaft which suits the Commodore rack)

Image

Image
Author:  argentina-slantsixer [ Tue Aug 21, 2007 4:01 am ]
Post subject: 
can't one just flip over 180° that very same setup? (I mean, the R+P?)
Author:  dakight [ Tue Aug 21, 2007 4:59 am ]
Post subject: 
Quote:
why would put the arranging in front of the K be bad?
As I understand it, the steering arms ( lower ball joints on an early A-body ) have to be swapped side to side to get them to face the front. When that is done the geometry is all whacked out and the toe-out on turns ( Ackerman ) is totally wrong.
Author:  Dart270 [ Tue Aug 21, 2007 5:54 am ]
Post subject: 
Have to ask Cameron about those r'n'p setups. He probably has seen them in action.

The Dodge City one looks like it should work well.

If I'm thinking about this right, as long as the inner tie rod pivots/balls are in the same spot as the stock inner tie rod end joint, then you should be in good shape. That may put the rack slightly inside the stock oil pan, which could be solved by notching the pan or by lowering the rack AND the outer tie rod end joint (easier with 17" wheels). Either way, it shouldn't be too hard. The idea is to elminate all the stock drag link, idler/pitman arms, and tie rods.

There is some up and down movement of the idler/pitman arms through their travel, which is maybe what Sandy is worried about?

Lou
Author:  james longhurst [ Tue Aug 21, 2007 8:53 am ]
Post subject: 
I seem to recall a green Duster in Mopar Action several years ago that was converted to R+P steering as a means of installing a hemi. The car was supposedly built as a stock appearing street cruiser but who knows? Anyway, I seem to recall the tie rods were very weird. Sorta triangular in shape in an attempt to maintain stock steering geometry. I'm in the process of moving, but I'll see if I can dig up the article soon.

-James
Author:  OzHemi [ Tue Aug 21, 2007 9:14 am ]
Post subject: 
I think that is one reason the one I have works/steers well, is the tie-rods are in a near-factory location so you do not end up with any bump steer issues. The pivot point of the inner socket is nearly in the same spot as the lower control arm point, so there is no strange steering characteristics.
Moving the rack up or down to get engine clearance would alter that, so that is why notching the sump is the better way to go.
Author:  slantzilla [ Tue Aug 21, 2007 2:30 pm ]
Post subject: 
I can tell you for a fact that just swapping lower ball joints side-for-side does not work, even on a drag car. It really screws thwe ackerman and induces so much bump steer that the car is literally unsafe to drive.

LRT makes a tube K and steering arms that make a nice handling drag car, but it is not recommended for street use. I do think it is autocross quality handling anyway.

AlterK-tion makes a super front steer setup, but it is a whole package. It is designed very well and is for autocross use.

I believe Lou is on the right track with rear steer. If you can get a rack that will put the inner tie rods where they are now, it will steer fine without any extra linkage.

The trick to making unequal length A-arms work with a rack is to get everything to move on the same arc. It can be done, but it takes some real thought.

My AJE front steer setup is so far off we may never get it to work. However, my buddy has already redesigned it so that it just might work after we re-engineer the whole thing. :shock:
Author:  Charrlie_S [ Wed Aug 22, 2007 4:09 am ]
Post subject: 
Why go to all the trouble and expense to install a rear steer R&P? I can understand installing a front steer setup, to get oil pan, header clearence, etc.
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