DIY Alignment -- Did I do it right?

[Captain Obvious]

Well said. Once I started taking stuff apart, I couldn't stop. Now I not only want to know... I simply HAVE to know.

But whatever works for any individual... If you want to take your car to a shop, then more power to ya! If you want to try it at home, that's great too!

[siteunseen]

Rossiz that's exactly how I was raised!  Pay attention to what you're doing and you'll be fine.  Now my Dad is 76 and takes things apart himself but has a hard time getting them back together, call Cliff he'll figure it out!  Makes me mad sometimes but he's taught me more than most Dads do so I owe him big time. 

Looking at parts on our cars, the shiniest side goes against something.  That's my favorite!  

[YoshiDori]

I know this is an older post... but I have some suggestions to people who may want to do this.

String alignments are just fine. We use alignment strings on our Pirelli World Challenge race car... along with all the other teams. We use smart strings that keep consistent distances which makes it a little quicker than with jack stands.

If you want to do this at home, the key is to know the difference in track width front to rear. I do not know track width on the Zs off hand, but for example, lets say the rear track width is 20mm more narrow than the front track width. In order to get the strings parallel to the car, we will pick an arbitrary number, for sake of demonstration lets say 100mm to set the distance of the strings to the center of the front wheels.

You want to set the height of the jack stands so the string is in the center of the wheel. Then measure and move the stands to get the string 100mm from the center of the front wheels. Then since the theoretical track width of the rear is 20mm more narrow than the front, you want to split that 20mm between the right and left side of the car. This gives you a 10mm difference per side. So then you move your stands to get the string 110mm away from the center of the rear wheel. 

Make sure you keep the string taught. Once you have the string 100mm from the front and 110 mm from the rear, you are now square with the car. Do this for each side.  It is tedious and takes some patience, but you are doing an alignment at home... you need to have patience...

Then to set the toe after centering the steering wheel, you want to measure the distance from the front lip of the wheel to the string and the distance from the rear lip of the wheel to the string.

If you want a stable but sporty feel, go 1mm toe in, this will make the front measurement 1mm longer than the rear. If you want a livelier feel of the car you can go zero mm toe where the front and rear are the same distance. And for track settings, depending on handling characteristics you want to achieve you can run up to 3mm toe out per side. 

Other things that can help is to make, make-shift turn plates. As you adjust toe, the tire moves and everything kind of binds up. With out turn plates, you need to keep wiggling the steering wheel and checking on it to make sure it remains centered. If you don't, then it can lead to a lot of frustration after you think you have it set where you need it only to look up at the steering wheel and it's off center. To avoid this on the cheap, you can get two floor tiles and some sand. You put the first tile on the ground, then sprinkle sand on top of it and set the other tile on top of the sand. This creates a simple bearing and allows the tiles to rotate easily on top of each other despite having the weight of a car on top of them. It's not perfect, but it helps and is simple and cheap to do.

I hope this helps with anyone looking to do any alignments at home. Feel free to ask me questions on the topic.

-Josh

[Namerow]

5 hours ago, YoshiDori said:

I know this is an older post... but I have some suggestions to people who may want to do this.

String alignments are just fine. We use alignment strings on our Pirelli World Challenge race car... along with all the other teams. We use smart strings that keep consistent distances which makes it a little quicker than with jack stands.

If you want to do this at home, the key is to know the difference in track width front to rear. I do not know track width on the Zs off hand, but for example, lets say the rear track width is 20mm more narrow than the front track width. In order to get the strings parallel to the car, we will pick an arbitrary number, for sake of demonstration lets say 100mm to set the distance of the strings to the center of the front wheels.

You want to set the height of the jack stands so the string is in the center of the wheel. Then measure and move the stands to get the string 100mm from the center of the front wheels. Then since the theoretical track width of the rear is 20mm more narrow than the front, you want to split that 20mm between the right and left side of the car. This gives you a 10mm difference per side. So then you move your stands to get the string 110mm away from the center of the rear wheel. 

Make sure you keep the string taught. Once you have the string 100mm from the front and 110 mm from the rear, you are now square with the car. Do this for each side.  It is tedious and takes some patience, but you are doing an alignment at home... you need to have patience...

Then to set the toe after centering the steering wheel, you want to measure the distance from the front lip of the wheel to the string and the distance from the rear lip of the wheel to the string.

If you want a stable but sporty feel, go 1mm toe in, this will make the front measurement 1mm longer than the rear. If you want a livelier feel of the car you can go zero mm toe where the front and rear are the same distance. And for track settings, depending on handling characteristics you want to achieve you can run up to 3mm toe out per side. 

Other things that can help is to make, make-shift turn plates. As you adjust toe, the tire moves and everything kind of binds up. With out turn plates, you need to keep wiggling the steering wheel and checking on it to make sure it remains centered. If you don't, then it can lead to a lot of frustration after you think you have it set where you need it only to look up at the steering wheel and it's off center. To avoid this on the cheap, you can get two floor tiles and some sand. You put the first tile on the ground, then sprinkle sand on top of it and set the other tile on top of the sand. This creates a simple bearing and allows the tiles to rotate easily on top of each other despite having the weight of a car on top of them. It's not perfect, but it helps and is simple and cheap to do.

I hope this helps with anyone looking to do any alignments at home. Feel free to ask me questions on the topic.

-Josh

Good tip concerning the use of floor tiles as turn plates.  For a light car like a Z, I wonder if it might not be a bad idea to load up the driver's seat with 150 - 200 lb of ballast (sand bags?) before doing a toe adjustment.

Re compensating for front-to-rear differences in track/tread when doing a string alignment:  The 240Z's wheelbase is 2305mm, while the front and rear track measurements are 1355mm and 1345mm respectively,  That would call for a 5mm step-out adjustment of the jack/axle stands at the rear.  This doesn't seem worth fussing over.  The error created by a 5mm lateral difference when played out over a 2305mm lengthwise distance amounts to only 0.005mm (i.e. two ten-thousandths of an inch).

I found a nice pictorial explanation of how to do a string alignment here:  http://www.hotrod.com/how-to/chassis-suspension/ctrp-1204-determining-wheel-alignment-string-your-car/

[YoshiDori]

You can, but that 5mm difference in track width will affect driving more so than not adding the weight will. Also tire pressure being different or one tire being worn more than another will affect it more than either.

On our cars if we don't have everything right the wheel will usually ends up off center. (Also happens a lot when we are lazy and don't use our turn plates)

In the end, yes, especially with a suspension that actually compresses a good bit, like stock suspension, it would only make everything better to put weight in the car to simulate driving.

Really just a matter of how patient you are.

Also that link is good for people to get an idea how to do it. I personally like the strings closer to the car than they have them. That way you can use a small metal scale instead of a giant square. Also the laser deal is cool too. I haven't messed with those yet... may need to try.