Align your 911 yourself!!!!

[snowman]

Thats right you can align yout 911 yourself. what so you need??? A piece of string, thats all. TO make it simpler you could aslo use a plumb bob and a tape measure.

The trick is NOTHING. All you have to do is the following:

1. Using the string measure from one side of the suspension to the other. Fold the string in half and mark the point on the front fo the cars body. Do the same for ther rear of the car. this point is the center line of the cars suspension. THE MAGIC point. Put a sheet metal screw in this point on both front and back fo the car..

2. Using the centerline of the car, ie the sheet metal screw, place a line sideways so that it is about one inch past the front wheel. Using the same length do the same for the rear.

3. Now streatch a line from the front to the rear using jack stands. The line is t he same distance from the center at both the front and rear. Now simply measure from the front of the wheel vs the rear of the wheel for the toe measurement. 1/8 inch toe in is typical. YOu can do both front and rear the same way.

4. For camber you need to measure the top of the wheel vs the bottom vs a plumb bob. typically the top should be one inch further in than the bottom of the wheel. Use your 7th grade geometry to fiigure the angle. You are aiming for about 1 degree negative camber for performance handling. In the rear you need about 2.5 degrees negative camber..

For caster you need more advanced geometry, see some books published on the subject. By the way caster is not to important unless the difference is more than o.5 degrees.

[masraum]

I agree with much of what you say here, but 1 inch for camber in the front sounds like much more that 1 deg neg, and 2.5 for the rear sounds pretty radical, especially if you only have 1 in the front.

Here's a really good thread including many specs and numbers.
http://forums.pelicanparts.com/showthread.php?threadid=6567&highlight=home+alignment+book

Here's another with a scan of a book on the subject.
Toe Adjust Techniquest

and another.
DIY Alignment/Corner Balance ?

[Zeke]

There is some important information missing. The car has to be on an absloutely level surface, something that is not easy to find. The car must be rolled into place with the driver seated and drivers weight must be kept in the seat for all settings. If you jack up the car to get at the tie rods, then you must repeat the roll in procedure to allow the suspension to settle. And yes, an inch is a bit much on the camber, but most will know that an eighth of an inch is what he meant. I can't verify that figure and it will vary with rim diameter. (All measurement are taken at the lip of the rim on known straight wheels).

[logician]

Hi,

For camber, I like to use a digital level. You don't need any kind of jig. All you need to do is pop the hub caps, and place the level against the plane of the hub cap mounting hole. Works great at the track!

-Juan

[snowman]

The angles I gave are correct. The inch depends on what rim you are using and there is no given answer, unless the rim size is known. Thats where the geometry comes in. Or you can get one of the books and it will give everything.

[logician]

> The angles I gave are correct. The inch depends on what rim
> you are using and there is no given answer, unless the rim
> size is known. Thats where the geometry comes in. Or you
> can get one of the books and it will give everything.

Assuming a 24" tire, 1" gives 2.4 degrees -- what snowman was aiming for in the rear. The front would have to be .4" in at the top to get 1 degrees.

But getting readings from the edge of the tire is not very accurate. The metal wheel lip is a better reference for the plumb bob method. There you're talking a distance of around 16" instead of 24", so the measurements are reduced proportionally.

-Juan

[masraum]

Here's an excel spreadsheet that will calculate camber based on the difference between the distance between the vertical and the top and bottom lip of a wheel (you input your wheel dia).



Given a 16" wheel measuring at the top and bottom vertical surfaces of the wheel to get 1 deg neg camber you would want about 9/32 of an inch difference between the two measurements.

It sounds like Juan may have struck upon the misunderstanding in 1. where the wheel/tire combo is measured, and 2. which camber we are talking about, front or rear.

Excel Spreadsheet
http://home.swbell.net/smasraum/camberchart.xls

One more thing, I found with a Fuch 16" that where I was measuring was actually about 16.5" across, so for simplicity I add .5" to the input rim diameter. If you really want to get accurate determine the distance between the two points that you use to measure, and then subtract .5" and you will get as accurate an answer as you can measure the distances A & B.

[logician]

Hi Steve,

Cool spread sheet! I think our computations are in agreement, and that snowman may have been correct in stating his 1" figure.

I thought snowman was talking about taking measurements at the tire not the wheel. His 1" number is correct for measurement taken at the tire (24 inche diameter) for his rear camber target of 2.5 degrees -- more accurately, 2.33 degrees as your spreadsheet computes. If he meant taking the measurement at the metal wheel, then the number should be more like .7".

-Juan

[jess p]

Good information Snowman, I used to use the same technique
when aligning my 914. It does work, however, plan on spending
at least 6 hours minimum to do this. I used heavy fishing string
as it does not streach.

[Wil Ferch]

Yes...use a line that doesn't stretch.
More....
I made a camber gauge from a 24" carpenter's level..looks a lot like the drawing that Steve Masraum put up. I have two threaded stand-offs as shown, and if you know the thread pitch, you can dial-up "X" number of turns to get the bubble level square, and measure camber directly ( need to have sheet made up with number of thread turns= "X" degrees..knowing the distance that the two stand-offs are apart).

As to toe-in...I use a method I've posted here before. Thumb tacks into the tread (!) portion of the front tires ...drop a plumb-bob to a metal conduit length running arcoss the front of the car and measure. Roll car back...drop plumb-bob now from the rear of the tire...and measure again. Presto...toe-in is known. Simple and more accurate than "laser" machines that aren't set up right or are operated by uncaring personnel.

---Wil Ferch

[TimT]

this is what I use to set the alignment on my cars



Though I do use strings lasers and levels when Im at the track, actually piano wireworks better than string. can be pulled taughter, and gives better resolution when reading the tape.

That big alignment machine isnt to portable

[Wil Ferch]

Here's my earlier post on home toe-in measurement:

turbo tie rod instalition

--Wil Ferch

[RickM]

Wow, great thread. A couple of pics with some advice on how to make the adjustments and this info would make a great tech article. I may try these techniques just to see what my car is dialed in at.

[masraum]

See this thread/link that includes a scan of a booklet written on how to perform home alignments on 911s.

Toe Adjust Techniquest

[snowman]

Everyone who races should read the book
" How to make your car handle" by Fred Puhn.

This book details everything one would ever want to know, including how to align the thing yourself in your garage.

[dickster]

i have printed off ronin's suggested booklet Toe Adjust Techniquest

its great, started alignment today.

i have a question on rear camber and toe. i know that i should adjust the camber first (i have 4 degrees neg at the mo), but can i leave the camber bolt/nut tightened when i adjust the toe? if not, when i adjust toe the camber setting may move?

front toe was easy, i used a combination of methods. took a piece of 2 x 1 wood to go the track width of the front wheels - that lays on the floor. two 12" pieces of same are attached at each end at 90 degrees so as to point upwards finishing somewhere near the middle of the tyre. going to rear of tyre first, put two pins in tyre next to top of 12" wood strips. then removing wood, rotate tyre so that pins go over top and to front of car. replace wood in front of tyres, and align with pins. the difference in where the pins meet the wood front to rear is the toe measurement - dead easy and worked a treat. remember that when you adjust the toe, you alter both the front and rear of tyre measurements - my dad had to point that out to me otherwise i would have been at it all day!!

for the rear i will have to use the strings.

[dickster]

another question. how do you get to the allen head bolt on the camber adjustment? the sway bar is in the way.

thanks.

[targa911man]

I used the book Steve posted, although I got it off dorkiphus, and was very satisfied with the results. I didn't do caster, only camber & toe-in. I used a plumb-bob for camber and it was relatively easy.