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Supra alignment tech

Supra
Alignment Tech

 This
is the long awaited alignment tech.  A
word of warning is necessary, price however.  To
do an alignment right takes patience and at least a day for the first one you
do.  Don’t think that you are going to do this in a couple of
hours if you want to do it right.  I’ve
done literally hundreds of race car and street car alignments, and the last
time I did a list member’s Supra, it still took me about 4-1/2 hours. 
If you can’t commit the time, you are probably better off trusting a
shop to do this for you, but be forewarned, results can be questionable from a
shop unless you know their work well.  Most
shops won’t take the time to do a perfect job…they couldn’t if they
wanted to charge reasonable rates.  You
KNOW you have done it right when you are done.

 

Equipment
needed:

 Camber
Gauge – you can spend a lot or a little. 
The Dunlop gauge is very heavy duty, but IMO expensive for what it
does…there are more accurate gauges for less. 
Pegasus Racing has a decent selection, but they don’t carry the TML
gauge anymore…theirs ranges from $120 for the digital model (not a bad
price) with $80 for the camber attachment (not absolutely necessary) to $221
for the Dunlop gauge, with the Longacre going for $174. 
TML’s camber gauge is generally less, you can contact them at PO Box
356, Hinsdale, IL 60521.  Pegasus can be reached at 800-688-6946.

 

Toe
measurement:

Toe gauge: you can
get a toe gauge, but the inexpensive ones can’t measure toe relative to the
centerline of the chassis.  Best
thing is with the string method, and it’s cheaper. 
You will need: Fishing line (preferably around 10-12 lb. test in a
highly visible color), get a 100 yard spool. 

6 concrete blocks
(the 8x8x18 inch ones) or something similar that can be used to run string
from one to the other under tension.

Plumb bob with string.

Several sheets of
construction board paper
that is the is as long as the width of the car
and at least 24 inches wide.

Steel retractable tape
rule with metric gradations (I use one from Stanley)

Steel ruler with metric
gradations
.

Chassis
manual for your car
– there are camber/caster adjustment tables that are
needed…however, if they are scanned in the Mkiv.com site, you can just print
them out from there.

Level
working area
.  The closer to
level, the better…if you’re garage floor is off by 0.25 degrees, this will
skew your camber measurements.  If you’re not sure (and just throwing a level on the ground
won’t tell you this, you need to level the spots the tires are on), there is
a measuring device sold in hardware stores to do this…it’s two tubes with
gradations on them and a flexible plastic tube connecting them. 
You fill them (and the flexible tube) with water until the water hits
the “0” mark on both of the tubes (the tubes have to be level for this to
happen).  Now you just place the
tubes on the spots where your car’s tires will be parked and you can see
which spot is high and which are not.  I
use linoleum tile or sheets of wood and metal to level out each spot.

 In
general, I feel that the best order in which to do an alignment is to take all
measurements first, then align the front, then align the rear. 
The most time consuming will be the toe measurement, as you have to do
a baseline measurement which will be referenced against the centerline of the
car.  This is basically for the
rear of the car, as the front typically doesn’t have a problem with this. 
If the toe is not referenced to the centerline of the car, the car will
“crab” in a straight line and you will have to put in some amount of
steering lock, to the right or left, to keep the car going in a straight
line…both sets of tires will be pointed ahead in parallel paths, but they
won’t be in line with each other.  You
could align the front tires to compensate but then they will be skewed in the
opposite direction from the centerline of the car and the unequal tie rod
lengths from one side to the other won’t be desirable in terms of bump steer
(no, I haven’t tested this, nor do I want to with the Supra, it’s a PITA
b/c you have to remove the springs to do it and hold the car up on ride height
blocks).

 Also,
it goes without saying to record down your various measurements as you go
along.  It behooves you to measure
the changes also, as this will give you a rough idea of how much change
results from “x” amount of tie rod or suspension “turns.” 
That way, you can make minor (very minor) changes at the track if need
be without having to go through all this.

 

 Determine
the centerline of the car:

 So
that you can envision what we are trying to accomplish, look at this diagram
and then go through the directions.

 

 

 There
are two methods to do this…one is the best way, but more of a PITA…it all
depends on how good a result you want.  If
you do it the second way, it depends a great deal on how accurate your body
panels are on your car.  If your
car’s ever been in an accident and panels replaced, unless you are sure of
the alignment of all panels, I wouldn’t even consider this method. 
In fact, I wouldn’t consider this method, unless I was in an extreme
rush, but it’s there for those of you who want to consider it. 
It’s for those who want to do it in less time than the best way to do
it.

 


First and best, but PITA method:

 1)     
With the car on a level surface, place the sheets of paper between each
set of wheels…you should tape the paper down, or have them underneath the
tires and the levelling pads so they stay still and flat. 
Make sure the steering wheel is straight ahead.

2)     
Underneath the car, use the plumb bob to determine a reference point at
an inboard suspension point at each wheel.  This can be any point, but should not be at a movable pivot
point (such as the cam adjustment points of the suspension), and must be the
same corresponding point on the other side of the car.  Mark this point on the paper with a pencil…be accurate,
take your time…an inaccuracy of 1mm is significant as we are dealing in ½
mm increments on some measurements.

3)     
Measure between the two points at each end, and mark a point halfway
between each set of wheels.  This
is the centerline.

 Now
I’ve had one Mkiv.com member make a good observation that most low cars, and
especially a Supra that has been lowered, will be difficult to find the
centerline as there is not much room to get down there and hang a plumb bob. 
So I have modifed the method so there are actually 2 of the correct
methods.

 1)     
With the car on a level surface, place the sheets of paper between each
set of wheels…you should tape the paper down, or have them underneath the
tires and the levelling pads so they stay still and flat. 
Make sure the steering wheel is straight ahead.

2)     
Jack up the car and take care to make sure that it is as even as
possible.  You may have to use
sheets of linoleum on each jackstand to ensure that the car is evenly up in
the air.  Off the top of my head
(without doing the geometries) I’d say that if the car is within a ½ inch
of being level you should be okay.

3)     
Underneath the car, use the plumb bob to determine a reference point at
an inboard suspension point at each wheel.  This can be any point, but should not be at a movable pivot
point (such as the cam adjustment points of the suspension), and must be the
same corresponding point on the other side of the car.  Mark this point on the paper with a pencil…be accurate,
take your time…an inaccuracy of 1mm is significant as we are dealing in ½
mm increments on some measurements.

4)     
Measure between the two points at each end, and mark a point halfway
between each set of wheels.  This
is the centerline.

5)     
Using two of your anchors, extend a length of fishing line from one end
of the car to the other, directly over the centerline. 
With the plumb bob, determine where the centerline is on the body of
the car on the nose and tail (preferably near the bottom of the nose and tail
– you’ll see why in a minute).  Using
a grease pencil or similar instrument, carefullly mark these points on the
car.

6)     
Now when you lower the car and raise it for adjustments, then roll it
back and forth to get the stiction out of the suspension, you only have to lay
out the lines underneath the car again using the marks you just made to
establish the centerline within minutes. 

 


Second method of finding the centerline:

 Simple
enough after you read the above section that I’ll basically outline the
procedure.  You look for two
points at each end of the car, two front, two rear, that is the center of the
car.  On the front you might open
the hood and measure between the two fenders and perhaps the two shock mounts. 
Using a long ruler/yardstick, extend this centerline past the nose of
the car and using a plumb bob, drop the point down to the paper you have on
the ground.  At the back you might
use the center of the wing or the center of the hatch glass. 
Now all you have to do is to extend this centerline for a couple of
feet forward and rearward of the car.

 

Measuring toe in:

1)     
 Stretch a section of
fishing line for two feet beyond the front and rear of the car, underneath the
car at ground level and lined it up with the two marks you’ve made on the
paper.  Make sure these are
taut…obviously you will have to anchor them betwwen 2 of the concrete
blocks.  Now you’ve extended the
centerline of the car.

2)     
Stretch another section of fishing line on either side of the car
running the length of the car and 2 feet beyond each end of the car. 
These two lines should be at about the height of the center of the
wheels and about 7.5 cm (3 inches) from them (any distance away from the
wheels would be okay but the further away you are the more errors can creep in
if you don’t keep your measuring ruler the same exact height and angle every
time…3 inches introduces very little error due to this). 
Using the plumb bob and the metric tape measure to set these up
parallel to the centerline section you are using. 
You will have to readjust the front and rear anchors several times to
get both right…patience is the key here, as well as throughout the
alignment.

3)     
Now the easy part…measuring the alignment. 
Go to each wheel and measure the distance from the string to the front
part of the wheel (measurement “A”) and the rear part (measurement
“B”) of the wheel.  Subtract
the front measurement (A) from the rear measurement(B)…if it’s negative,
the wheel is toe’d in.  Positive
and it’s toe’d out (these are just my conventions, as long as you know if
it’s toe in or out, that’s fine).  The
rear’s are critical…be sure they are equal left and right.

 

 Measuring
Camber:

 1)     
Take the camber gauge and put it agains the wheel, making sure it’s
vertical as you’re looking at it (it should not be inclined towards the
front or rear of the car).  If
your wheels are scraped up from curbs, you can measure on the tire as long as
you take care not to allow any raised black lettering affect the angle of the
gauge, or any bubbles in the tire (if you have any damage).

2)     
Measure the camber according to the directions of the camber gauge.

Measuring Caster:

 1)     
Caster is measured either directly or indirectly. 
Directly means you use a camber gauge and place it directly on the
steering knuckles and measure their rearward inclination. 
Most people don’t do this as it is very difficult to get a gauge into
a wheel well and accurately measure this. 
The indirect way is by measuring the camber with the wheel turned
“x” degrees to the right, then measuring again with “x” degrees to the
left, and subtracting the smaller of the two measurements from the larger one.

 Now
you take all your measurements together and decide where you need to go from
here.  The first thing is to make
sure your rear wheels are equally toed on both sides…if not, you will need
to adjust this.  Although it’s
not totally accurate, use the Toyota chart to determine how you need to to
adjust the rear wheels.  NOTE –
you must be sure to observe the convention of how they reference their
alignment marks – you must turn the the adjustment cams from the “bolt
side” and it is from this side that they reference clockwise and
counterclockwise.  The convention
that is used by Toyota is either clockwise or counterclockwise looking
straight at the head of the adjustment bolt. 
For the front suspension, the you have to look at the front cam from
the rear of the car looking forwards, and for the rear cam you will be looking
at it from the front of the car looking back towards the rear of the car.  At the rear suspension, you will be looking at the front cam
from the front of the car looking back at the rear of the car, and the rear
cams you will look at them from the rear of the car looking towards the front
of the car.  Sounds a little
confusing, but once you’re underneath the car all will be much clearer.

 This
will be a basic starting point.  Note
also that in my manual they have the conventions backwards (i.e., the
direction for increasing negative camber should have been clockwise at the
front cam and counterclockwise at the rear cam, not counterclockwise and
clockwise as is illustrated in the manual). 
You will find out after you do your first adjustment. 
Anyway, you can adjust toe and camber simultaneously, and will probably
have to as both will most likely need to be adjusted. 
For this you will need to jack up the car and loosen the nuts on the
adjustment cam bolts.  Be
forewarned, if your car hasn’t been aligned before, they will most likely be
very tight, and a breaker bar is recommended. 
A helping hand would be useful too, not only to help loosen them, but
to hold the adjustment cams in place while you tighten down the nut after you
adjust the cams.  The basic
procedure is this:

1)     
Decide how much you need to adjust the cams.

2)     
Loosen the nuts on the cam adjustment bolts. 
TIP – leave some “torque” on the nuts so that the cam adjustment
bolt doesn’t just change adjustment from the weight of the car.

3)     
Turn the bolt until the cam has moved the appropriate number of marks.

4)     
Hold the bolt while you tighten the nut. 
You don’t have to go monster tight at this point (i.e., torqued to
Toyota specs) as you will most likely need to fine tune this.

5)     
Lower the car and measure the changes.

6)     
Assess whether or not the changes are in the direction you want (if
they’re in the opposite direction, then you know the Toyota manual is
backwards on the conventions).

 Ater
you adjust them, you need to roll the car back and forth several times to
“settle” the suspension.  Now is the PITA part…you have to re-establish the
centerline of the car again to measure rear toe.

 You will have to
repeat until you get the results you want. 
Go back and forth with the toe and the camber measurement until they
are both where you want.  If it
seems you have to compromise somewhere, compromise with the camber and not
with the toe (i.e., get the toe exact, but the camber can be up to ¼ degree
off and not be significant for our intents and purposes – this does not
apply, however, if you’re roadracing).

 The
front toe is easier (by far).  Basic procedure is to adjust the toe first, then camber, then
recheck the toe.  To check the
toe, I go with total toe (it is not necessary to reference them to the
centerline, as long as the 2 toe links are close to each other in length, the
manual says no more than 1 mm difference). 
To measure the toe:

 1)     
Take your tape measure and with a helper, go the front of the tires and
measure from the outermost tire groove on one tire to the same groove on the
other tire.  This is measurement
A.  You will have to measure below
any body work or chassis…although this is not the center of the tire, it is
close enough.  If this isn’t
accurate enough for you, you can use the centerline method to establish
measurement lines again as you did for the rear tires and measure to the wheel
or outer wall of the tires.

2)     
Repeat for the rear of the front tires. 
This is measurment B.

3)     
Subtract A from B, this will be your total toe in or toe out. 
If the number is positive, it is toe’d in, if negative, it is toe’d
out.  0 measurment is 0 toe in.

4)     
Check the length of the tie rods…they should be within 1 mm of each
other, if not adjust them so that they are.  You need to loosen the jam nut on them and the boot clip
before you do so.  Take note of
how many turns you use on the tie rod to achieve this. 
Normally you will not need to do this.

5)     
Adjust the toe by turning the tie rods equally on both sides. 
Take a note of how much you turn the tie rods (and be as precise as
possible…I get down to 1/8 of a turn on my measurements, even 1/16
sometimes).  You will have to
observe the thread direction on the rods to know which way to turn them to
either draw the front of the tires closer together or spread them further
apart (I’m making the assumption that everyone is a reasonably adept at
mechanics so that they can determine this…if not, email me and I’ll tell
you how to do this).

6)     
After the adjustment, roll the car back and forth and take a new
measurment.  Correlate the change
in toe to the amount you turned the tie rods. 
Use this for your next round of adjustments.  For instance, if the toe-in was 4 mm, and you want 0 mm…you
turn the tie rods out ¼ turn…and the new measurement is 4 mm
out…therefore, ¼ turn on both tie rods equals about 8 mm change in toe.  You need to go back 4 mm (to get to 0) so you need to turn
the tie rods 1/8 turn IN.

7)     
Make the appropriate change and measure the car again.

 Now
you want to adjust the camber.  Similar to the rear, there are front and rear adjusting cams
on the car.  Again, use the manual
to determine the changes you need, both for camber and caster. 
Loosen the adjusting cam nuts, then turn the bolts to the desired
change and tighten down the nuts.  Take
the measurment and see how close you are to the desired measurment. 
This will be similar to the other adjustments where you make gross
adjustments, then fine adjustments until you reach the desired adjustment. 
Once done, you will have to measure the toe again, which will most
likely have changed.  Readjust the
toe then take the camber and caster measurements again, adjust if necessary. 
This can go back and forth a few times and thus take a lot of time.

 When
done make sure you torque down the eccentric cam adjuster bolts to spec. 
If you don’t you run a real risk of your carefully hand done
alignment gradually moving out of alignment!

 After
this, you are done…probably at least 6 hours later.

 

Questions? Comments?
> E-Mail
Me

 

 


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