DIY Alignment -- Did I do it right?

[racer47201]

Can you not get a 4-wheel thrust angle alignment for a 280Z? I know on a 280ZX Turbo I owned, 4-wheel thrust angle was advised, Of course that was for a ZX.

[wheee!]

Very important on high HP/Tq vehicles. My 370Z was checked at 0.00" of thrust angle and 0.01" of negative toe. Under hard acceleration things can get squirrelly fast if you're not aligned. I'm not sure if it is as critical on the 280 though... Recommended I'm sure.

[Zed Head]

There are pictures around the interweb of the rear wheels of various Z's moving back in the wheel well under hard launches.  The factory rubber bushings let the rear wheels toe-out and move back.  Under braking the front bushings allow the wheels to move back and toe-out also (the TC rod is what keeps the wheel from moving back and the rubber donut they used to position it compresses easily).  The factory stock S30 bushings are pretty loosey-goosey in general, and non-adjustable except for front wheel toe-in.  It's an inexpensive sporty car.  That's why a piece of string, some tape, and a Sharpie are all you really need to do a full alignment procedure on the stock parts.

There are many aftermarket parts that will let you do much more.  But the factory parts are basically done once they're bolted on.

[gundee]

Thanks for the tips. I am adding this to my bucket list for Spring when I can get back in the garage.

Mine tracks pretty well but I am really curious as to what the rear wheels read since the factory

gave us no adjustment. 

[charliekwin]

Well, tonight was a bust!  As soon as I get the car out of the garage (after prepping dinner and kids for bed), I hear a passerby yell from across the street "dude! Is that a 240Z?!"  30 minutes later, and there was no possibility of getting anything done.

About that punched mark, the FSM says to line it up with slits in the U joint, but I don't see anything that looks like that on the column.  They aren't referring to the steering coupler U joint in the engine bay, are they?  Or just leave it at 12:00?

[Captain Obvious]

The U-joint coupling has a punch mark too, but I'm definitely talking about the end up by the steering wheel. They say "punch mark on the top of the upper column shaft":

Maybe yours is rusty and you just can't see the mark? Maybe they didn't put them on all the cars? Too late today, but I should be able to get you a pic tomorrow.

Edited February 16, 2016 by Captain Obvious

[charliekwin]

No need Capt, I just realized that screenshot I posted isn't of the steering hub.  Sheesh.  I swear, I'm usually a half-tick brighter than this!

I think I need a vacation.

[rossiz]

i did mine w/string and she drives straight as an arrow. the way my dad taught me may not be race/performance perfect, but it's actually really simple and works fine: start w/the car on a flat, level surface, tie a string to the rear hub (a spoke on mine) so it's pulling around the sidewall of the rear tire at the center of the wheel, then pull it 20' in front of the car and tie to something so that it's tight and just grazes the sides of the front tire at the center of the wheel. i screwed a long, piece of wood to the garage door so i could slide the strings (both sides) left/right to get it adjusted where i want it. you will immediately see if the tire is turned to the left or right, when you get the string just grazing the sides of the tire, if the wheel is turned it will bend the string. set up the other side of the car the same way, measure the strings out at 20' in front of the car then at the front of the car and adjust them till they're parallel. set the steering to center, then adjust the tie rods a little at a time till you bring the wheels paralles with the strings then add whatever toe you want - i kept it as close to parallel as i could get it.

i may be missing something, but i don't think that it really matters where the rear wheels are at to adjust the front - i'm simply using a point (the sidewall of the rear tire) to anchor the string so i can pull it out in front of the car - this is where you get the parallel measurement, and at 20' it's surprisingly accurate. i don't bother w/jack stands cause you can't pull really hard on them to get the string tight without them moving (mine are too light), plus the rear wheels are already there, so nothing to pull out of the garage. 

i'm sure there are all sorts of more detailed, professional ways to do it, but i use the car as my dd to commute and the odd spirited romp - no serious track time, and this method worked great. did it last summer and have put about 5K miles on it since and the tires are wearing just fine.

i did this after refreshing the steering rack isolators, control arm bushings, t/c rod bushings and adding stiffer sway bars and replacing worn out ball joint boots. the front was way out and i got it nice and straight pretty easily.

[Consigli]

Just had my 280Z aligned and wheel balanced at the Lexus dealership. It use to shimmy, shake, vibrate, wander and drift to the right at speeds above 60MPH. After they got done it now runs silky smooth & straight right up to 100MPH, which is as fast as I dare take it since I don't want go to jail on felony speeding. 

Now the point of all this is that modern alignment and road force wheel balancing equipment uses technology such as lasers and computers to get the job done right. But I think if you spend enough time fiddling with the kite string, chewing gum, plumb bob and bubble balance you should eventually be happy with the results too. 

[Captain Obvious]

I know you said you didn't need it. but here's a pic anyway. This is the punch mark at the steering wheel end of the steering shaft. Mark is at about 12:00. Now I don't know if all the years and all the columns had the mark, but every one I've been into had that punch:

 

[Captain Obvious]

I'm a theory guy, and I used to completely dismiss the home shop alignment stuff thinking that there was no way you could do something in your garage and end up with something as good as you what you could get using an expensive laser guided rack. But I've spent some time analyzing the geometry and I now believe the theory is sound.

My claim is... "If done right, the front tire tread measuring technique can yield an accurate thrust angle compensated alignment."

I can explain the theory, but it'll take some sketches. I'll throw something together when I get the chance.

[John Coffey]

A laser alignment rack improves speed and efficiency - period.   All the geometry involved can be measured with lasers, string, angle finders, plumb bobs, tape measures, metal rules, dial indicators, etc.  Accuracy is 100% down to the skill of the operator, whether using string or a laser.  A laser alignment rack lets a less skilled and low payed technician do the work while getting good results (make it all green).

A few times I've had customers bring in a "laser race aligned" 240Z and found that the alignment was off - most often in thrust angle and caster.  I've fixed it using string and other manual tools. One customer took the car back to the shop that did the "laser race alignment" and the techs said the car was perfect (thrust angle, cross camber, caster, etc.)  They had told the customer that the only way to fix the car was to pull the frame.

Edited February 16, 2016 by John Coffey