Strut Modifications
Camber Plates
Dando's (510-659-7900) provided the entire shock, spring, and camber plate materials, and much information on modifying the Z struts for adjustable camber, and adjustable ride height. The camber plates installation in the strut towers is well explained in the instructions included with the parts. The modification gives one approximately 1-1/2" of camber adjustment at the top of the strut. The modification will yield this much movement only if the smaller diameter springs are used (thus allowing more room for movement inside the strut tower). Also, after I finally reach the desired ride height on the car, I found that the 0 degree camber setting for the front wheels is at the extreme outside end of the camber plate adjustment slot. The closest setting to 0 degrees camber I can get at the rear wheels is about 1 degree of negative camber with the plates set at their most extreme outside end of the adjustment slot (remember, the camber becomes more negative as the car is lowered). Finding, through racing experience, that less negative camber is needed in the rear, I have since moved the camber plates about 5/8" further out, to gain some additional positive camber adjustment.
Camber Angles with an 18" measure
| Camber in Degrees @ 18" |
| .1 | .031" |
| .2 | .063" 1/16" |
| .3 | .094" |
| .4 | .125" 1/8" |
| .5 | .157" |
| .6 | .188" 3/16" |
| .7 | .220" |
| .8 | .251" |
| .9 | .283" |
| 1.0 | .314" 5/16" |
| 1.1 | .345" |
| 1.2 | .377" 3/8" |
| 1.3 | .408" |
| 1.4 | .440" 7/16" |
| 1.5 | .471" |
| 1.6 | .503" |
Adjusting Ride Height with New Spring Assembly
Dando's (510-659-7900) provided the entire shock, spring, and camber plate materials, and much information on modifying the Z struts for adjustable camber, and adjustable ride height. The springs used in this modification are 2-1/2" I.D. springs that are 10" long and are rated at 200 lb./inch. The springs will sit on a steel scuff plate, which in turn sits on an aluminum "tube nut" that is threaded so that this tube nut can be screwed up and down on a threaded aluminum tube that fits around the strut tube and rests on a steel ring welded onto the outside of the strut tube. The threaded tube is 5" long, so with a spring compression of 2", and knowing the approximate ride height of the car, the location of the strut tube can be determined so that you still have some adjustment of the tube nut up and down the tube to adjust the ride height of the car, or to adjust the weight on any particular wheel. On my Z, the bottom of the front wheel threaded tubes is 4-1/4" above the shoulder of spindle casting at the bottom of the strut tube as measured from the engine side of the strut. The rear threaded tubes are one inch taller (5-1/4") from the same reference point. With the threaded tube location determined, a steel ring of thickness is welded around the strut tube at the location where the threaded tube should sit. The top of the spring is then covered with an aluminum piece which fits under the camber plates but seperated by a bearing, allowing the weight of the car to rest on the spring.
Tokico Competition Strut Inserts
Dando's (510-659-7900) provided the entire shock, spring, and camber plate materials, and much information on modifying the Z struts for adjustable camber, and adjustable ride height. The Tokico strut inserts I bought from Dando's is a non-adjustable, low pressure, competition gas insert. The inserts will not match the strut, in terms of length, but will fit inside the strut tubes. The inserts are really suited for strut tubes that have been shortened so that a lowered car will still have the full range of shock travel instead of bottoming out the strut. The strut inserts also only come in one length, so the front and rear modifications will differ from each other because the rear strut tube is longer than the front strut tube.
For the front struts I started by measuring the strut tube excess length by measuring the distance from the top of the insert body to the top of the strut tube (taking into consideration the thickness of retainer cap, and the correct adjustment of same). I then used a pipe cutter to cut the same amount out of the middle of the tube, where the tube wall thickness was even, and above the point at which the spring perch (or threaded tube perch in my case) would be. This location eliminated any undue stress from forming at the weld of the two tube halves. Once the tube halves are welded together, the strut insert can be inserted into the strut, and the retaining cap screwed on tight, and hopefully leaving only a couple of threads exposed, indicating a good fit.
The rear struts are identical in the modification as the front struts except for the difference in tube length. The rear struts are longer than the front to begin with, but the inserts for the front and rear are the same. So with this in mind, I made an aluminum 1" spacer to fit between the bottom of the strut tube and the strut insert, thus raising the insert by 1", allowing the rear strut to be cut longer than the front one, and thus maintain a full range of shock travel at the rear, just as it is in the front.
A less costly alternative to this would be to use a Z front insert in the rear strut, allowing the rear strut tube to be cut down, and then use an insert from another make of automobile (such as a VW Rabbit) which is shorter than the factory Z insert, in the front strut. The struts I modified had tubes approximately 14-1/2" long in front, and 15-1/2" long in the rear as factory length. When I was finished with them being shortened, the front tubes were 12" long, and the rear tubes were 13" long. When I say tube length, I mean the length from the top of the strut tube, down to the shoulder at the top of the cast spindle/axle housing that is fitted over the tube end and welded there by the factory.
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