Toe Adjust Techniquest - Page 4

ohecht · 07-14-2003, 05:19 PM

Here is the camber tool I made today. Fairly simple, just some common carpentry tools glued together to fit my 17" wheels. Probably $10 in parts and 5 minutes in labor.

It gave me very repeatable readings to within 1/16th of an inch.

I leave the bottom t-square at 6" exactly, put it on the bottom lip of the rim, then adjust the top t-square in both position on the rim and length from the rim until the bubble on the top of the level is centered. I can then turn the top thumbscrew to lock the top t-slide, and the measurement is "captured" and can be read later, etc.

Olivier

ohecht · 07-14-2003, 05:26 PM

I have been having some issues trying to set my alignment after replacing all of the rear bushings, etc. I am trying to learn and test my skills during this unique opportunity (without it being professionally set).

Ray Scruggs pamphlet says to have 3/4 to 1" rake, with the rear higher than the front. I have this now and the rear fender lip is 25.5" on both sides with 17" tires. This seems right relative to the front, which was untouched, but it looks high. I measured the door sill and spring plate angles with an angle finder before disassembly, and I am sure I got the t-bar splines back in the right positions, as the angles went back to their exact positions.

Using the Euro specs in the Bentley manual, however, I have negative ride height in the rear using the method of measuring the difference between the hub center caps and the t-bar caps. My hubs are at 12", and the t-bars are at 11.5", which is the opposite of the listed spec. This is all with 17" wheels.

Does anyone have the numbers I should look for for Euro height with 17" wheels (the car has always been very low, maybe lower than Euro spec in the front)

Any advice would be appreciated.

Olivier

RoninLB · 07-14-2003, 08:38 PM

well Oliver..
the factory height spec for the front is measured from the center line of front part of the spring, and the centerline of the wheel axle.. the '77 Carrera difference is 108mm +/-5mm.. US is 93mm +/- 5mm.. max difference is 5mm from left to right

the rear is measured from the center line of the spring, and the center line of the rear axle.. '77 Carrera is 12mm +/- 5mm.. US is 37mm +/- 5mm.. max difference is 8mm

RoninLB · 07-14-2003, 08:51 PM

Hey Olie..
forgot.. the book says to have a full gas, spare, etc. ....

ohecht · 07-15-2003, 03:26 AM

My problem is that, with 17" tires, measurement A is .5" higher than B on both sides, which gives me "negative ride height" using the hub center and torsion bar cap method. Fender lip height is 25.5" on both sides, though.

Olivier

69911e · 07-15-2003, 05:26 AM

For rear tow thrust alignment (in a narrow body car with same front and rear tires) simply sight rear tire to properly aligned and centered front tires. Rear tires should sight about 1/4 inch inside the widest portion of the front tires(the front is about .5" wider than the rear), this gives about 0 tow in. This method allows for greater accuracy because instead of 2' tires your are aligning on the approx. 12' wheelbase, so even if you are off by 1/4 inch the tow will be off by only 1/24 of a inch. This method can also use a laser pointer to sight, and can be used for wide bodied cars with a couple additional steps.

ohecht · 07-15-2003, 09:50 AM

I have wider wheels and tires in the rear, but that does make sense in terms of the diameter of the tire vs. the wheelbase of the car.

Has anyone seen "negative" ride height numbers like mine, or is that common for larger than stock tires?

Olivier

RoninLB · 07-15-2003, 10:52 AM

Quote:

Originally posted by ohecht

or is that common for larger than stock tires?

factory measuring is independent of tire diameter

RoninLB · 07-15-2003, 10:55 AM

maybe you could jack the rear a small bit to simulate factory specs. for a baseline

ohecht · 07-15-2003, 11:22 AM

I'm not following you on that one, Ronin.

Olivier

RoninLB · 07-15-2003, 11:54 AM

I think your trying to figure your height based on the new wheels and tires? you can simulate the factory measuring technique by raising the rear tub and leaving the wheels on the ground, with a floor jack till the numbers are stock.. because you have "negative" numbers now.. I may be the one confused here

ohecht · 07-15-2003, 02:00 PM

The tires and wheels have been on the car since I got it, I was just surprised when I got a negative number while checking the height against factory Euro specs. I understand what you are saying about jacking up the body to see what the factory spec would look like, but I think it would be 1 full inch higher, which doesn't seem possible.

The car has always been low, but I have had nothing to compare it to and it handles very well. Is it possible to lower a 911 all the way into the negative range and still not have massive tire rubbing, etc. with 17" tires?

Olivier

masraum · 07-15-2003, 02:28 PM

Most/many people go lower than the factory height, so don't worry about it.

luftgekuehlt · 10-01-2003, 09:41 PM

Quote:

Originally posted by JasonAndreas
Ray Scruggs, Application Developer
DINMAR (U.S.)
755 Baywood Drive, Suite 190
Petaluma, CA 94954
Phone 707.658.5114
Fax 707.658.5155
rscr-@oacis.com

Good research ... how did you did this up?

Here's the hits from Google

http://www.google.com/search?sourceid=navclient&ie=UTF-8&oe=UTF-8&q=Ray+Scruggs+20%2DA+Scenic+Ave%2E+San+Rafael+CA+9 4901

http://members.rennlist.com/dan10101/docs/S_MISC.doc

http://members.rennlist.org/dan10101/docs/S_ALIGNMENT.doc