The LH/LX/UC 4 cyl Starfire, 6 cyl and V8 k-frames are all basically the same. The only significantly different k-frame is the one used with the Opel 4 cyl which has a different engine mount and can not be used with the 6 cyl and V8 engine mounts.
Early LH k-frames do not have the sway bar mount holes however these can be easily added. A cover for the steering rag joint coupler was added during the LX model. The UC k-frame has a small bit of steel rod welded to the top of the outer ends of the k-frame just under the UCA. The purpose of this rod is unclear, it appears to be an additional bump stop to prevent the control arm binding on the k-frame when the suspension is at full extension as the higher UCA bolt position reduces the effectiveness of the rubber bump stop. The UC k-frame also has a reinforcing washer spot welded to the upper shock mount.
The main method of identifying the k-frame is via the position of the Upper Control Arm (UCA) mount bolts. The bolt holes are 7/16" the bolt has splines which makes it a press fit into the hole.
LH/LX non RTS 50mm LX RTS 65mm
|
|
|
|
|
|
||||
The bracket in view A is welded to the k-frame for the Starfire 4 cyl, 6 cyl and V8.
|
|
|||
The LH and LX use the same UCA although the LH arm may have been made from thicker steel. The ball joint is offset 0.5" (12.7 mm) on the UC version of the UCA , this gives more positive caster than the LH and LX UCA's. which are symmetrical.
|
|
|||
The geometry of the LCA is the same throughout all models. The LH and LX LCA are identical with the exception that the LH arm 5.59 kg is made from 5/32" (4.22 mm) and the LX is made from 1/8" (3.7 mm) pressed steel. The LCA on the UC 4.74 kg is also made from 1/8" (3.31 mm) pressed steel. The LH and LX LCA do not have steering arm bump stops. The UC LCA has steering arm bump stops. The UC LCA has a larger hole for the shock absorber to fit through. The LH and LX LCA shock hole can be enlarged to the same size as the UC.
|
|
|
|
|
The A9X uses HZ one tonner stub axles.
| Model | Position | Included Angle | Part Number |
| LH/LX Drum | Both | 9 | 7448795 |
| LH/LX Disc | Left | 9 | 9934548 |
| LH/LX Disc | Right | 9 | 9934547 |
| L34 | Left | 9932964 | |
| L34 | Right | 9932965 | |
| A9X | Left | 7.5 | 9943695 |
| A9X | Right | 7.5 | 9943696 |
| UC Disc | Left | 9 | 92000163 |
| UC Disc | Right | 9 | 92000164 |
The A9X Stub Axle lowers the car 20 mm and increases negative camber by 1.5 degrees . The track is not increased by either the stub axle or the HQ discs. The A9X track was increased as a result of fitting different offset rims. The A9X or Harrop reproduction steering arms should be used with the A9X stub axle to correct the bump steer caused by the altered suspension geometry. The A9X and HZ one tonner stub axle have been heat treated which gives them a blue tinge. There is also more steel around the lower ball joint mount. The HZ car stub axle is identical in geometry and has a different part number.
If you fit A9X stub axles and change the springs to retain the same ride height as you had with the Torana stub axles then the track will change a small amount due to the change in the angle of the lower control arm at ride height. When the lower control arm is horizontal the track will be at its widest. As the lower control arm moves away from horizontal the track will reduce as the stub axle is swung through an arc.
|
|
|
|
|
This is the angle that is built into the stub axle. It is often incorrectly referred to as the King Pin Inclination (KPI).
King Pin Inclination (KPI)
KPI is the inward tilt from vertical in degrees. The KPI is
the sum of the camber angle and the included angle built into the stub axle.
Camber Angle
Camber angle is the angle made by the wheels of a vehicle; specifically, it is
the angle between the vertical axis of the wheels used for steering and the
vertical axis of the vehicle when viewed from the front or rear. It is used in
the design of steering and suspension. If the top of the wheel is farther out
than the bottom (that is, away from the axle), it is called positive camber; if
the bottom of the wheel is farther out than the top, it is called negative
camber.
Replacing the Torana stub axle which has a included angle of 9 degrees with a A9X/HZ stub
axle
with a included angle of 7.5 degrees will increase negative camber by 1.5 degrees. Camber
is reduced by removing shims from between the k-frame and the UCA pivot arm. You
will need to remove approximately 0.25" of shims to compensate for the
difference in included angle between the Torana and A9X/HZ stub axles. Track cars typically run
significantly more camber than a street car so the increase is negative camber
is a bonus.
|
|
|
||
The steering arms are different for each model. The tie rod end of the arm gets progressively lower and longer thoughout the LH/LX/UC/A9X. Reproduction A9X steering arms are available from Harrop.
The UC has more caster than the LX due to the offset ball joint in the UV UCA. When the caster is increased, the tie rod end of steering arm is raised. The lower UC steering arm corrects the changes to the steering rack geometry caused by the caster increase.
|
LH |
Left |
9928327 |
|
|
Right |
9928326 |
|
L34 |
Left |
9935249 (GM5249) |
|
|
Right |
9935250 (GM5250) |
|
LX |
Left |
9928329 (GM8329) |
|
|
Right |
9928328 (GM8328) |
|
A9X |
Left |
92001894 |
|
|
Right |
92001893 |
|
UC |
Left |
9947249 (GM7249) |
|
|
Right |
9947248 (GM7248) |
|
|
|
|
|
|
|
|
|
|
I have
collected the following rack travel measurements as another method of
identifying racks.
LH
rack travels 63 mm for 1.5 turns
UC
rack travels 55 mm for 1.5 turns
If the UC rack is 20.4:1, the rack travels 55 mm
for 1.5 turns and there are 3.68 turns from lock to lock then the total rack
travel is 135 mm.
Using
the above figures.
The LH rack travels 63 mm for 1.5 turns of the wheel.
This
would require 135 / ( 63 / 1.5 ) = 3.21 turns for lock to lock which gives a
ratio of 360 / ( 65 / 3.21 ) = 17.87 which is close enough to 18:1.
On
this basis the 25:1 rack would travel 135 / 4.51 * 1.5 = 45 mm for 1.5
turns.
|
Degrees |
Time |
|
1.00 |
1:00 |
|
0.75 |
0:45 |
|
0.50 |
0:30 |
|
0.25 |
0:15 |
| Castor | Camber Left | Camber Right | |||||
|
Description |
Degrees |
Time |
Degrees |
Time |
Degrees |
Time |
Toe |
|
Axistr LX |
+1.0 to +1.5 |
+1:00 to +1:30 |
+0.25 to +0.33 |
-0:15 to -0:20 |
0.00 to +0.25 |
0:00 to +0:15 |
0.00 mm |
|
Axistr Power Steering |
+2.5 to +3.0 |
+2:30 to +3:00 |
-0.25 to -0.33 |
-0:15 to -0:20 |
0.00 to +0.25 |
0:00 to +0:15 |
0.00 mm |
|
UC/A9X |
+2.00 |
+2:00 |
-1.00 |
-1:00 |
-1.00 |
-1:00 |
+1.50 mm |
|
Gregorys Manual LX |
-1.00 to -2.00 |
+1:00 to -2:00 |
+1.00 to 0.00 |
+1:00 to 0:00 |
+1.00 to 0.00 |
+1:00 to 0:00 |
+1.59 mm |
|
LH |
-1.00 +/- 1.00 |
-1:00 +/- 1:00 |
+0.25 +/- 0.75 |
+0:15 +/- 0:45 |
+0.25 +/- 0.75 |
+0:15 +/- 0:45 |
0 +/- 1/8” |
|
L34 |
-0.50 +/- 1.50 |
-0:30 +/- 1:30 |
-0.25 +/- 0.75 |
-0:15 +/- 0:45 |
-0.25 +/- 0.75 |
-0:15 +/- 0:45 |
0 +/- 1/8” |
|
A9X |
+1.00 +/- 0.50 |
+1:00 +/- 0:30 |
-1.00 +/- 0.50 |
-1:00 +/- 0:30 |
-1.00 +/- 0.50 |
-1:00 +/- 0:30 |
3/16" +/- 1/16" |
|
Gregorys Manual UC |
+1.00 to +3.00 |
+1:00 to +3:00 |
-2.00 to 0.00 |
-2:00 to 0:00 |
-2.00 to 0.00 |
-2:00 to 0:00 |
0.00mm to +0.95 mm |
|
UC/A9X |
+2.00 +/- 0.30 |
+2:00 +/- 0:18 |
-1.00 +/- 0.30 |
-1:00 +/- 0:18 |
-1.00 +/- 0.30 |
-1:00 +/- 0:18 |
+1.50 mm |
|
|
|
|
|
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
