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DIY Alignment: Lessons Learned

 
Old 07-25-2017, 07:54 PM
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Poor-sha
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Default DIY Alignment: Lessons Learned

I just wrapped up doing a track alignment on my 2017 C7 Z06 at home. My target was the DSC Sport recommended track alignment. I purchased and installed the AMT camber kit so that I could make sure the alignment stayed locked in. It also gave me some interesting data on how the suspension geometry of the C7 works.

Now this process took me 2 weekends and every weeknight in between to get right. After this experience I will never trust a dealer or shop that just throws you car on the rack for an hour to do the job properly.

I found that even using slip plates, rear slides, bouncing the car on the rack, and doing short drives down my washboarded road it still took a good long drive to get the suspension to settle after you lifted the wheels off the ground to make an adjustment. More than once I thought I had it nailed only to come back and find out that the camber had changed from the drive as things settled.

I ended up setting all of the AMT camber plates at position 2 front and 2 rear and used a variety of shims and washers. Setting them at 3 didn't get me the camber I needed even with no washers or shims but will probably work well for a less aggressive alignment. It's also a bit of a pain to change the camber plate settings as you have to lift the car, remove the wheels and use a pry bar to move the suspension. Luckily once you get the right setting the rest is fine tuning at the upper control arms.

Each lower control arm (LCA) has both a forward and an aft leg that have an AMT eccentric on each end. As long as both the forward and aft LCA are set to the same position the front caster seems to settle nicely at 7.5 deg and the rear at 0 deg. The upper control arms also have a fore and aft leg to them with each leg having two bolts that hold it to the frame.

In order to get to 0.7 positive (rear leaning) rear caster just put a single OEM washed behind each of the bolts on the fore leg of the rear upper control arm. From there out you just just camber with equal shims in all UCA bolts and caster doesn't change.





In the pic you see the screwdriver hanging down from the fore leg of the UCA. The easiest way to adjust the shims behind the UCA is to only loosen one leg at a time slightly, then use a screw driver where you see it to pry up the dog bones. Otherwise they tend to rotate down and are a pain to get a shim behind. You can also add washers by just loosening one bolt on a leg and removing the other bolt to insert the washer.

For those that are wondering, I tried adjusting caster at the LCA but with the AMT kit a move from 2 to 3 at the fore section of the LCA results in caster of ~1.5.

I also used 200 lbs of ballast in the drivers seat and a full tank of fuel when I aligned the car. Changes in fuel and ballast definitely changed the camber so I found that I had to refill the fuel tank after I made the long drives to settle the suspension. Good thing I'm also trying to get 1500 miles on the car so I can take it to the track this weekend.

I found that the RF suspension needed one additional washer behind each stud to be even with the LF wheel when ballast was added. On the rear the RR needed about an extra 1 mm shim than the LR (I will need to verify this next time I have the wheels off as I've forgotten now). Other than that I just added shims equally to both sides until I got the camber right and then I set toe.

I'll update this post when I get a chance to determine which shims I used.

Last edited by Poor-sha; 07-25-2017 at 10:10 PM. Reason: fixed LCA to UCA washers. Added pic.
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Old 07-25-2017, 08:58 PM
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Thanks for the detailed info!!!

I don't quite understand the statement above. Do you maybe mean to put washers behind the fore leg of the rear UPPER control arm??

Last edited by BEZ06; 07-25-2017 at 10:52 PM.
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Old 07-25-2017, 09:09 PM
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I had the same question. Thanks for the inital writeup poorsha. Fwiw for changing shims on the uca, i have had the best luck by unbolting all 4 uca nuts, compressing the suspension slightly, which allows the uca trunions to slide off and on the studs fairly easily.
What equipment and method did you use? I want to download david farmers instructions but his link is down.

Last edited by lrobe22; 07-25-2017 at 09:10 PM.
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Old 07-25-2017, 10:07 PM
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Poor-sha
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Originally Posted by BEZ06 View Post
Thanks for the detailed info!!!

I don't quite understand the statement above. Do you maybe mean to put washers behind the fore leg of the rear UPPER control arm??
Sorry, you're right. It should have been washer behind the upper control arm. I'll correct my original post.

Compressing the suspension helps but I've not been able to compress it enough with the car on the lift without the whole car tilting to make it slide on more easily. I'll post a follow-up tomorrow with the specific setup I used.

Last edited by Poor-sha; 07-25-2017 at 10:08 PM.
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Old 07-25-2017, 10:26 PM
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Old 07-26-2017, 05:43 AM
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Thanks for the tip on setting the caster. I will provide this input to my shop today when I drop the car off to have the AMT kit installed and car aligned.

I see you did not use the AMT stud kit. Do you feel it would have been any easier adjusting the shims with it, or the same?
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Old 07-26-2017, 06:13 AM
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Originally Posted by 08G8V8 View Post
Thanks for the tip on setting the caster. I will provide this input to my shop today when I drop the car off to have the AMT kit installed and car aligned.

I see you did not use the AMT stud kit. Do you feel it would have been any easier adjusting the shims with it, or the same?
I recommend the stud kit if you are going to be changing the alignment from street to track using the shims somewhat frequently. It does make changing shims easier, but it also reduces wear and tear in the threaded inserts in the frame.

However if you're going to just set it and forget it then the studs aren't all that necessary.
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Old 07-26-2017, 10:02 AM
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Originally Posted by 08G8V8 View Post
Thanks for the tip on setting the caster. I will provide this input to my shop today when I drop the car off to have the AMT kit installed and car aligned.

I see you did not use the AMT stud kit. Do you feel it would have been any easier adjusting the shims with it, or the same?
I agree with Mark. The studs will keep you from stripping out the threads if you do regular adjustments for track and street. I like that solution better and the studs are easy to install if you do one at a time. I wouldn't recommend taking all the bolts out and then trying to do it. I replaced mine one at a time and it was fairly easy.
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Old 07-26-2017, 08:54 PM
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As far as the tools I used here is a list:

1) 4 post lift. I've had mine for years but I'm pretty sure this is the model. The car fits fine but the rear tires do hang off the ramps a bit. That's one of the reasons you can't use toe plates to measure toe on the lift. Like most lifts, mine has a not on each post that can be used to level the stops. Use an 8 foot level to make sure the lift is perfectly level when on the stops.
http://www.gregsmithequipment.com/At...rage-Pro-8-000

2) QuickJack BL-5000. I uses this on top of the 4-post lift ramps for when I need to take the wheels off the car to add/remove shims or adjust the camber plates. You can set toe with the car on the ground.

3) Turn plates and sliders. I used the Longacre turn plates for the front and budget sliders for the rear. The front turn plates are pricey and I ended up buying them direct from Longacre when they had a refurb set. Now that I know what I do about the way the caster works on this car I really don't need to measure front caster anymore as long as the front camber plates are set the same and I'm happy with 7.5 degrees.
http://www.ogracing.com/longacre-aluminum-turn-plates
http://www.ogracing.com/longacre-eco...ide-slider-set

4) Tenhulzen string frames and camber/toe gauge. This worked really well for me although setting up the string frames takes some time to get right. I was getting solid repeatable results and as someone who owns a few different camber gauges and adapters this was the best one I've tried. You also should get a small machinists ruler to help measure when centering the strings.
https://www.tenhulzenautomotive.com/...ignment-system
Amazon Amazon

5) Steering wheel holder. I found out the hard way that sometimes when adjusting toe the steering wheel moves. I used to this to hold mine in place. Usually I would get it set and then lower the power wheel to get it tight.
Amazon Amazon

Other than that it's a bunch of hand tools to adjust things. Hope this helps.
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Old 07-27-2017, 06:03 AM
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Huge thanks! What instructions did you use, if any? Tenhulzens?
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Old 07-27-2017, 07:19 AM
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Originally Posted by lrobe22
Huge thanks! What instructions did you use, if any? Tenhulzens?
Yes. Mainly the Tenhulzen. Although it's fairly self explanatory other than measuring caster in the front.
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Old 07-27-2017, 05:05 PM
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do you have pictures of the AMT plates in position?
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Old 07-27-2017, 05:38 PM
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Old 07-27-2017, 07:28 PM
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The AMT camber plates are a must for track use. You will also need the Granatelli Adjustable Toe Links with AMT locking plates if you are trying to run -2 degrees or more in the rear. The OEM rear toe links do not have enough adjustment range. With the rear AMT camber plates set at 2 in all positions, camber at -2.1 degrees, the best toe setting was .4 degrees toe out each side. Rear most AMT camber plates set at 3, forward camber plates set at 2 produced -1.8 degrees camber and .05 degree toe out each side but the caster is off.
Front is not an issue and you can get 3 degrees + of negative camber with no toe adjustment problems with the AMT camber plates.

If you do it yourself you need alignment tools and a level surface.
If you do not have a level surface you are wasting your time!
You can do it on a level garage floor but adjusting the front toe links is difficult. A four post lift makes the job easier.
Tools needed:



A string system like Tenhulzen:






Turning plates for the front wheels to measure caster and adjust toe:



Floor tiles under the rear wheels to adjust toe and patience!

I have checked my aglignment on three different Hunter Hawkeye sytems and they all showed different readings. Not sure if there is some calibration issues that aglignment shops are not doing.

Last edited by wstaab; 07-28-2017 at 10:09 AM.
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Old 07-27-2017, 07:42 PM
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Originally Posted by AKKutz View Post
do you have pictures of the AMT plates in position?
BEZ06 posted some pics in this thread. Although I just noticed that he appears to have an extra washer than I do. I just have the lock washer and nut.

https://www.corvetteforum.com/forums...post1595217009
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Old 07-27-2017, 08:12 PM
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Originally Posted by Poor-sha View Post
BEZ06 posted some pics in this thread. Although I just noticed that he appears to have an extra washer than I do. I just have the lock washer and nut...
Yes - after I started torqueing down that one on the right, the plate wasn't seating correctly in the indent in the frame. I removed the nut, lock washer, and plate. I filed down the plate very slightly (you might be able to see it's kind of silvery on the edge) so it fit into the indentation.

The plate looked sort of gouged up from the lock washer, so I put on another washer - I don't know whether that will affect the lock washer's ability to "lock" in the torque spec or not, but it just seemed like it would keep the plate from getting messed up.

The one on the left (and none of my other plates) have that extra washer. If I ever start re-aligning and moving the position of the plates, I'll decide then if I want to put on that extra washer on any of the other bolts/nuts on other LCA bushings.

.
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Old 07-28-2017, 10:00 AM
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Wstaab, Nice set up. I have recently picked up Quick Trick tools and plates, along with the GM tool for the rear caster. I have the AMT kit with studs. And various other measuring devices. The only thing I don't have is the lift. I know this is going to be a PITA without one. I do have a fairly level garage floor. I was hoping to cheat by following Poor- sha's settings..... we shall see. My goal are the DSC specs as I am installing that as well. I have the Granatelli Adjustable Toe Links coming.....what does AMT have for these?

Last edited by AKKutz; 07-28-2017 at 10:04 AM.
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Old 07-28-2017, 10:41 AM
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Please note that I also had to add shims to get the camber right. I'll try to document that when I next get the car on the lift.

Also you will be amazed how the little things can easily sway your measurements. Having a "pretty flat" floor is going to skew things unless you can devise singer sort of shim system to level the car.
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Old 07-28-2017, 10:52 AM
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I'm sure I will have to floor tile the rear to level with the turn plates. It be sweet if there was some way to get my car up high enough to adjust toe without lifting, adjusting, driving, measuring lifting to re-adjust etc..... Might have to dig a pit in my garage
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Old 07-28-2017, 12:07 PM
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When I had my C6Z I used to use Smart Strings to align the toe front and rear. However, they didn't fit on the C7 so I sold them. With the C7 I went back to my old way of setting toe.

First, let me say when I had my house built I talked to the build site manager about meeting the floor level specs so I could install a Max Jax. He more than met my expectations. The floor is as close to dead nuts level width wise as my 6 foot carpenters level with a digital level placed on top if it can read (0.0). Lengthwise it has a .3 degree downslope toward the garage door. I have markings on the floor where I need to park the car to get those numbers (just in case of small dips in the surface).

I have a LongAcre digital acculevel that I can attach to iron brake rotors or to a longacre 3 point mount that attaches to the rims. That lets me set front camber and caster. In the rear I use the longacre gauge to measure camber and a Wixie gauge attached to the GM Rear Caster adapter to set caster. To set rear caster I place my 6 ft carpenter's level on the floor under the car next to the rear tire where I am measuring caster and zero the gauge to take out the .3 degree downslope.

One thing I do with all four camber readings is double check them with my 24 inch Sears Digtial Laser Level by placing it vertically against the tires (away from the tire bulge at the bottom). This works very well as a check and lets me have a way to quickly check the alignment when I don't have a complete set of tools. I set the rear camber and caster first and then drive the car to settle the suspension. I keep doing this until I get the readings i want after the last drive. It takes more than a drive around the block to settle the suspension so I have about a mile loop I drive around the development.

The last time I did this I had a -2.4 camber reading at both front wheels and +7.5 degrees of caster. I also had -1.7 degrees camber at each rear wheel with +.7 degrees of caster. When ever I want I can drive into the garage and use the laser level to check camber at all 4 wheels and if it hasn't changed I can be pretty sure that caster and toe haven't changed either since they are both affected by camber changes.

To set toe I use a set of LongAcre Toe plates and two tape measures. I place the toe plates against the rear wheels and adjust the toe as close as I can measure it with the tape measures which are marked at 1/32 increments. Anything smaller is useless since I can't see it all that well. I can set rear toe by having the rear wheels on some home made slip plates and adjusting the toe with the car on the ground. Once I have toe straight I place the laser level on top of the toe plates and aim the laser forward to a measuring stick I have mounted on a jack stand. The stick is inset into the front hub and I adjust the toe on each side so I have the toe setting I want and the laser measurement on each side is as close to equal as I can get it. That sets thrust angle. Once rear toe is set and locked in I move to the front which means I have to lift the car to make the adjustments. Basically, the method is the same as in the rear other than lifting the car. The final thing I do is place the laser level aiming at the measuring stick set up at the rear hub and adjust toe to get the steering wheel straight.

I haven't used camber plates yet since I have been lucky not to have the stock lca cams slip. Each one is marked where I set it last and when I have been under the car I haven't seen any slippage. I know those cams can slip since I had them slip on my C5 and I did use the plates on my C6 but so far I haven't had a problem with them as long as I tighten them to their full torque spec. Over the last three track events I have run over a lot of rumble strips and they haven't moved.

Right now I am contemplating switching to studs for the UCAs so I can easily change the number of shims behind the UCAs in order to change camber to a more street compatible setting without eventually damaging the threads in the frame.

So far the car hasn't suffered any changes in the control arm bushings so the alignment is staying where I put it but I know there will be a time where I will need to make changes due to changes in the bushings (if not from wear it will be because of age).

One other thing. If strings are used the toe, thrust and steering wheel angle settings can be done a lot easier as far as making the measurements. However, if you have to lift or move the car to settle the suspension they tend to screw you because they have to be removed and reset each time you move the car. The smart strings were supposed to be able to move with the car but I found I had to drive too far to settle the suspension and having the hood in the air didn't make that easy to do.

Bill

Last edited by Bill Dearborn; 07-28-2017 at 12:11 PM.
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