Should I do my own alignments?

[ntmatter]

After a full Viper Days season, I'm getting comfortable enough pushing the car to realize the difference a proper alignment can make. I've seen some camber/caster and toe alignment tools for sale in catalogs and my local race shop, and I'm trying to figure out if it's worth the $700 or so that these tools would cost me. Given that I did nearly 20 track days this year, and expect to do maybe 10-15 next year, would it be reasonable for me to learn to align the car myself? Does anyone have any experience with doing this work - is it worth the effort or should I just pay a local shop to do it for me?

Thanks for any advice,

A

 

[GTS Dean]

It really all depends on how dedicated you are to maximizing tire life and performance. A good alignment can be worth several seconds per lap. I've been doing my own alignments for about the last 3 years. It takes me about an hour per corner to do the car, including changing brake pads and rotors between street and track duty.

Do it enough and the next thing you know, other Viper buds will be at your house the week before track time getting theirs done too.

You definitely need to invest in a lift to make it easier.

 

[Tom and Vipers]

Anyone want to outline the method using strings?

Thanks
Tom

 

[GTS Dean]

Strings are a PITA and I don't use them.

 

[kverges]

OK, Dean-O

If you don't use strings, how do you set toe? I would love to know a way to set toe on all four corners w/o strings. I just used the SmartString setup from the folks who came out with the SmartCamber tool, and I actually did not mind the strings at all. You mount the alignment bars to the car, so when you go up & down on the lift you don't have to worry about the car coming back down in a different position relative to the strings.

Also, how do you deal with re-torquing the A-arm cam bolts. Theoretically they should be torqued with the suspension loaded, but that is pretty hard to do unless you have a lift that lifts the car by the wheels and slider plates under each wheel so the cams can be rotated easily (basically a full alignment platform is key).

So do us an alignment treatise for the site ;-)

 

[GTS Dean]

First, I run all the shock adjusters to zero. My lift picks the car up by the wheels. I have a jack bridge under the car so I can make adjustments to the wishbones without ruining my cams. I snug the nuts down, then lower the car onto slip plates and jounce vigorously. Set caster and camber as desired, then torque the wishbones. Then, I get the laser out and do each side of the car.

I use a rotating laser to create a parallel plane to the CL. It screws to a plate and the plate slips under a bracket on each side sill. The brackets are exactly parallel to the centerline of the car. Measure the toe difference directly off the wheel and add about 30% for 1/2 the total toe. Frankly, I've done it enough times that I can eyeball the car's toe and be within 1/16" most times.

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[kverges]

Very nice! But I think I am relegated to string since it goes better with my stone knives and bearskins garage setup.

 

[Tom and Vipers]

Dean,

The plane defined by the rotating laser:

Is this plane normal to the floor? (It would have to be to measure the toe right off of the wheels.)

If yes, then isn't it difficult to make that plane parallel to the car center line? (Actually, that is the part that stumps me with the string method.)

RE: String Method:

It is easy to make the 2 strings parallel to each other, but how do you make them parallel to the car centerline?

If you setup the string from average wheel offsets, this assumes that the front and rear tracks are centered on the chasis.

Tom

PS. I've seen too many drawings and datums to make this easy!

 

[GTS Dean]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Tom and Vipers:
Dean,

The plane defined by the rotating laser:

Is this plane normal to the floor? (It would have to be to measure the toe right off of the wheels.)

If yes, then isn't it difficult to make that plane parallel to the car center line?
<HR></BLOCKQUOTE>

Tom,

Check the thumb screws and bubble vials on the laser. The laser head is at almost the same elevation as the axle centerline. I checked parallellism of the laser plane by pulling a tape off a string running down the centerline of the chassis and measuring where the beam hit the tape. Same mm offset at the front and rear on each side give you the parallel reference plane. Measure back to the wheel face at 3 and 9 o'clock.

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As far as the strings go - you would really need some reference marks that are plumbed from an extended centerline off the frame (either on the floor or the bodywork.) Then you simply measure off some convenient distance - say 42" - each way off the marks. Square or plumb up to strings supported by jackstands. I've seen several folks use the stripes on a Viper to approximate the CL, but that could present issues due to misaligned bodywork. The biggest problem with using strings on the floor is getting to the tie rods. Your car MUST be on slip plates to effect a change, and it helps greatly to squirt a bit of silicone spray under the boot on the inboard end of the tie rods about once a year so they don't twist and tear when adjusting.