Ackerman change by moving box & idler arm

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Ackerman change by moving box & idler arm

Postby Zanie » Thu Mar 17, 2016 12:03 am

So the Ackerman problem is aggravated by the 1 inch longer steering arm on the S-10 spindle......... right?
because
The outer tie rod ends move in an arc with the center being dictated by the ball joint.
The inner tie rod ends move in an arc with the center being dictated by the swing of the pitman arm/ idler arm.
The arcs move in opposite directions(outers back & inners forward) which causes the toe to change
The S-10s longer arm changes the geometry two ways: 1) the arc is bigger for the outer tie rods and 2)the outer tie rods are moved 1 inch further forward.
I am contemplating moving my steering box and idler arm mounting points 1 inch forward.
As in re drilling the "frame".
Its no small feat as all the mounting holes must be sleeved.
This would get decrease of one of the "changes" caused be the spindle swap (#2).

Also
This might help the slowed steering response.....or make it worse.

Anyone tried this?
Dan
73 vega wagon LS1 T56 build thread
http://forums.h-body.org/viewtopic.php?f=20&t=36579
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Re: Ackerman change by moving box & idler arm

Postby Smiley » Thu Mar 17, 2016 4:24 am

S10 spindles are only 1/2" longer than H-body spindles, there are some G-body spindles that are longer than S10's.
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Re: Ackerman change by moving box & idler arm

Postby avewhtboy » Thu Mar 17, 2016 9:30 am

Zanie wrote:So the Ackerman problem is aggravated by the 1 inch longer steering arm on the S-10 spindle......... right?
because
The outer tie rod ends move in an arc with the center being dictated by the ball joint.
The inner tie rod ends move in an arc with the center being dictated by the swing of the pitman arm/ idler arm.
The arcs move in opposite directions(outers back & inners forward) which causes the toe to change
The S-10s longer arm changes the geometry two ways: 1) the arc is bigger for the outer tie rods and 2)the outer tie rods are moved 1 inch further forward.
I am contemplating moving my steering box and idler arm mounting points 1 inch forward.
As in re drilling the "frame".
Its no small feat as all the mounting holes must be sleeved.
This would get decrease of one of the "changes" caused be the spindle swap (#2).

Also
This might help the slowed steering response.....or make it worse.

Anyone tried this?


I have not contemplated trying to move them forward but barring other interference issues, yes that sounds like it would help.

I was looking at a couple things to fix this also. I autocrossed my car the other day and the ackerman problem is woefully obvious and
is exacerbated by the S10 spindles for the reasons you stated.

I was wondering about reversing the tie rod connections at the center link. Basically bolting the tie rods inner links to the opposite side
of the center link.

The other thing I was looking at, is shorter steering arm and Pitman arms. They would correct ackerman and quicken the steering.
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Re: Ackerman change by moving box & idler arm

Postby cjbiagi » Thu Mar 17, 2016 10:57 am

I don't think you can reverse them because the centerlink and tie rods are tapered and only fit in one direction.
Clyde.........75 Monza 2+2
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Re: Ackerman change by moving box & idler arm

Postby avewhtboy » Thu Mar 17, 2016 12:18 pm

cjbiagi wrote:I don't think you can reverse them because the centerlink and tie rods are tapered and only fit in one direction.


Yes that's what I figured would keep this from being "simple".

I would think there a way using different rod ends maybe ? or weld the holes shut in the center link and drill the taper
from the other side?
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Re: Ackerman change by moving box & idler arm

Postby Smiley » Thu Mar 17, 2016 6:27 pm

You could use a fast ratio power steering box with the matching S10 steering arm and idler to get the same radius on all parts.
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Re: Ackerman change by moving box & idler arm

Postby avewhtboy » Thu Mar 17, 2016 6:52 pm

Smiley wrote:You could use a fast ratio power steering box with the matching S10 steering arm and idler to get the same radius on all parts.


Is the S10 steering arm and idler arm shorter? and will they fit the Vega box?

It seems like i read the S10 has different spline on the steering box.
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Re: Ackerman change by moving box & idler arm

Postby Smiley » Thu Mar 17, 2016 8:32 pm

What I am saying is to use a 12.7:1 box with an S10 arm and Idler when using S10 spindles to reduce Ackerman by having the same radius and then move the box if needed.

quick ratio box off of a 1995 Grand Cherokee is just under 3 turns lock to lock. The GN and Camaro boxes had internal stops, limiting the degree of travel of the pitman arm. All of the quick ratio boxes are 12.7:1, meaning for every 12.7 degrees the steering wheel is moved, the pitman arm moves 1 degree.


Camaro internal stops on the Iroc were set to limit steering wheel turns to about 2.25 lock to lock so the 245/50 16" tires wouldn't rub. It had a 12.7:1 ratio.

Those particular models of Grand Cherokee ('92-'98) all have 12.7:1 quick ratio Saginaw steering boxes that have 87 degrees of travel, or about 3 turns lock to lock, allowing a sharper turning radius. A regular Cherokee has the normal ratio box.


SAGINAW POWER STEERING BOXES
BODY STYLE YEAR CODE RATIO TOTAL TRAVEL
Monte Carlo SS ’85 to ’88 YA 12.7:1 78 degrees 30 minutes
Fullsize Chevy F-41 '88 to '90 WZ 12.7:1 87 degrees
Fullsize Chevy F-41 '91 to '94 CP 12.7:1 87 degrees
Fullsize Chevy F-41 '95 CT 12.7:1 87 degrees
Camaro/Firebird ’82 to ’93 WS 12.7:1 70 degrees
Camaro with FE2 ’85 to ’93 XH 12.7:1 64 degrees
Camaro ’67 -- 17.5:1 87 degrees
Camaro ’68 to ’81 -- VR 67 degrees
Chevelle ’66 -- 17.5:1 87 degrees
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