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Shelby drop and lowering spring

Horseplay said:
The "drop" is both down and back. It changes a lot of the geometry. Thing is you never knew just exactly what the alignment specs were before you started. I've had experience were I thought I had a good set-up on my truck, it tracked great, etc. but I started to notice uneven tire wear which prompted me to check it out and it was not even close.
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I thought only the 65-66 were down 1" and back 1/8". The 67-70 were just down 1".
 
Long ago, I learned to align a 66 Corvair. For toe. We made a tool with a long piece of perforated galvanized L steel, and put 1/8 " Weldon rod on each end (looped and attached using a bolt n washers). Then placed that assembly at the front mid point of the tires (lining it up with a groove in the tread) and then carefully moved it to the aft, noting the difference
 
Horseplay said:
The "drop" is both down and back. It changes a lot of the geometry. Thing is you never knew just exactly what the alignment specs were before you started. I've had experience were I thought I had a good set-up on my truck, it tracked great, etc. but I started to notice uneven tire wear which prompted me to check it out and it was not even close.
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The 67 is straight down.


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I'm trying to understand more about casteI. I saw and read a few articles on caster and I understand the concept and adjustment. But if you can get the correct caster but using the adjustment rod, why would I have to mess with the shims? I assume I have to mess with the shims only if I can't get caster with the rod?

If I did have to mess with the shims, how do you take them out and reinstall without basically removing the upper control arm?


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You need to make sure the bottom of the wheel doesn't move too far forward so that it contacts the lower front fender when turning. Sometimes you need to shim the top backwards to keep that from happening.
 
Chevy S10s actually have a similar shimmed UCA setup, so any reputable alignment shop should be able to take care of it. That said, who knows if the on duty alignment tech has done one recently, or if they're willing to vary from the ancient manufacturer alignment spec. Definitely not as simple as your run of the mill Honda alignment.
 
msell66 said:
You need to make sure the bottom of the wheel doesn't move too far forward so that it contacts the lower front fender when turning. Sometimes you need to shim the top backwards to keep that from happening.
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This is exactly what I had to do. I did gross adjustments by adding shims to the front UCA bolt and fine adjustment to dial each side in with SorT adjustable strut rods.
 
Patrick Stapler said:
'66. I would think the process is the same however.
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Question. Is the correct: To get positive caster you would lengthen the the rod, which pushed the lower control arm aft?

Also in doing alignment which do you do first or does it matter toe/camber/caster?




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Lengthening the strut pushes the LCA back which removes positive caster.

Since I have started doing my own, I do camber, caster (because it affects camber which you should read check after caster), then toe.
 
Patrick Stapler said:
Lengthening the strut pushes the LCA back which removes positive caster.

Since I have started doing my own, I do camber, caster (because it affects camber which you should read check after caster), then toe.
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Okay so shortening obviously pulls it forward creating a positive caster which we would want +2 to +3.5.

Okay I get it.

So I'm assuming people will run into a problem if the pull it to much forward the lower controll arm will also hit it attachment to the frame where the centric adjustment is? And if that's the case then you need to add a shim in the front of the upper control arm and also making sure you are clearing the front fender.




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Which is why I add shims to the UCA front bolts first then fine tune with the strut. This also keeps you from disengaging too much of the heim joint threads from the strut rod.

I would also note, my car drives much better at +4 caster than it did at +3. Searches much less at highway speeds. That change alone also changed the camber from -1.5 to -1...which IMO is enough for street use.
 
Patrick Stapler said:
Which is why I add shims to the UCA front bolts first then fine tune with the strut. This also keeps you from disengaging too much of the heim joint threads from the strut rod.

I would also note, my car drives much better at +4 caster than it did at +3. Searches much less at highway speeds. That change alone also changed the camber from -1.5 to -1...which IMO is enough for street use.
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So before I go back in, as I need to replace the upper control arm, I should do a rough check in the camber. Because I imagine the only way to add or remove the shims is basically taking off the control arm? Or can you slide them in there with the nuts loose and tire still on?


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No need to remove the nuts all the way...just enough to get shims in. If you have some lock wire (wire used for locking a bolt or nut) you can create a shim 'pack' by tying them together to help manage it.
 
Patrick Stapler said:
If you are replacing the UCA, you will need to redo the alignment.
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Not sure if you read my entire thread. I have only done the right side: drop springs/shocks/Shelby drop/roller perches/. But I noticed I needed new upper control arms. But I decided to finish the job to see how it sits. I did take out an 1/8 shim on both the front and back. Right now they are equally spaced. I think with one each :1/8,1/16,1/32.

So now I'm waiting for my upper control arms before I go back in.

If I need more +caster without making anymore adjustment to the rod would I add a front shim? Or remove a back shim? Or am I ass backward again.




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