Alignment Specs ?

[Jack P.]

Hi , I have taken the car in to a alignment shop to get an idea of what the present front alignment specs are ( I did not do any work on front) and to set the camber on the rear after the installation new strut rods and cam bolt kits and all bushings.


I did not bring any shims this time as I felt that they could do the rear camber without much c-2 corvette experience, plus I wanted to run the specs past the forum members for suggestions.

*******If you know, looking at my pictures.......how would shims be added or taken away (if possible) to get me to 2*. There is not much bolt left on both right and left a arm. ?


I have attached two photos of my left and front A-arms. Do I have any room left for shims to get the + 2 in castor on the front.?





This is how my car sits now. 1966 L-79 Convertible stock with power steering.

Left Front Right Front


Camber 0.1 + -0.1


Castor +1.1 +1.1


Toe +0.26 +0.26


Total Toe 0.52


Steer Ahead 0.00




Left Rear Right Rear


Camber -0.4 -0.5


Toe +0.5 -0.16


Total Toe +0.33


Thrust Angle+0.33


Pass Side Picture Fender on top side of picture





Driver Side Picture

[Duke W.]

Re: Alignment Specs ?

Front camber readings are confusing. Is it +0.1 -0.1?

Is toe measured in inches or degrees?

Duke

[Jack P.]

Re: Alignment Specs ?

Trouble with formatting. The first numbers are the driver side reading followed by right side in degrees as I copied them from print out

jack

[Mark E.]

Re: Alignment Specs ?

The front camber is still confusing: "Camber 0.1 + -0.1" ??

Some thoughts:
- The UCA bolts should NOT have washers. This will help with the limited length of the UCA bolts.
- Use all new UCA nuts and shims during the alignment. Make sure you're using the purpose-specific locking nuts for the UCA.
- Can you shorten the PS belt? That will give you more clearance between the pump and the UCA bolt.
- You typically want negative, maybe zero toe.

Google "Dick Guldstrand Corvette alignment specifications". I've used his C2/C3 "touring" specs with nice result. He recommends a lot of caster (but less than the +2 deg you mention) to help with steering feel, and since you have PS you won't need to worry about the resulting increased effort.

[Mark E.]

Re: Alignment Specs ?

Is that rust build up around the RF UCA bolt?. Be sure to inspect that carefully to insure structural integrity of the frame, arm and bolt. And clean it all up so you're not shimming over flakes of rust. (Is shimming a word?)

[Duke W.]

Re: Alignment Specs ?

Nominal toe-in should be 1/32" at all corners (for radial tires) and it's very important that rear toe is equal on both sides. Front toe will always equalize when driving, but the steering wheel may be cocked, so you often have to tweak the tie rods to get the steering wheel dead centered drving down a straight road with mininum camber.

If toe is measured in degrees the following relationship can be used to convert 1/32" toe-in to degrees toe-in.

a = toe angle, in radians (2pi radians = 360 degrees)
r = radius of installed tire, inches

a = (1/32)r

For OE diameter 7.75-15 tires (~13.5" radius) 1/32" toe is a toe angle of about 0.0023 radians, which is about 0.133 degrees.

Cross readings should be as low as possible to minimize rear thrust angle. I like to see it no more than 0.1 degree, and zero is even better!

Your caster readings are acceptable, but more would be better. Caster can be increased with little effect on camber by moving a shim from the front to rear position, but you only have one front shim on one side. The control arm or frame may be tweaked.

The "touring setting" camber is zero front, -1/2 deg. rear, so you are pretty close, front and rear. The biggest out-of-spec measurements are rear toe.

Duke

[Jack P.]

Re: Alignment Specs ?

Yes + 0.1 on left front. - 0.1 on right for camber

[Jack P.]

Re: Alignment Specs ?

Nominal toe-in should be 1/32" at all corners (for radial tires) and it's very important that rear toe is equal on both sides. Front toe will always equalize when driving, but the steering wheel may be cocked, so you often have to tweak the tie rods to get the steering wheel dead centered drving down a straight road with mininum camber.

If toe is measured in degrees the following relationship can be used to convert 1/32" toe-in to degrees toe-in.

a = toe angle, in radians (2pi radians = 360 degrees)
r = radius of installed tire, inches

a = (1/32)r

For OE diameter 7.75-15 tires (~13.5" radius) 1/32" toe is a toe angle of about 0.0023 radians, which is about 0.133 degrees.

Cross readings should be as low as possible to minimize rear thrust angle. I like to see it no more than 0.1 degree, and zero is even better!

Your caster readings are acceptable, but more would be better. Caster can be increased with little effect on camber by moving a shim from the front to rear position, but you only have one front shim on one side. The control arm or frame may be tweaked.

The "touring setting" camber is zero front, -1/2 deg. rear, so you are pretty close, front and rear. The biggest out-of-spec measurements are rear toe.

Duke

Hi Duke and thanks for the help.

I would like to thank all of you for your comments. Based on those and the other forum posts, I will have the shop try to do this.




Front


Camber 0 * LF and RT
Castor + 1.1 now try to get to 1.5 or more on both sides if possible without changing Camber
Toe 1/31 " Degrees ?




Rear


Camber - .5 Both sides
Toe 1/32 " in Degrees ?


I will bring shims. The real problem will be Castor, Do I have room for shims on one side and only one shim to remove on the other . The car handles well , I just want I little more castor as indicated for power steering. I am not changing the arms .....


Pass Side Picture Fender on top side of picture



Driver Side Picture

[Steve G.]

Re: Alignment Specs ?

You might also want to have your alignment shop check your ride height. While loss of adjustment (no shims left) can be caused by roll in of the frame area at the control arm mount, it is most often due to sagged springs. A good alignment starts with correcting ride height issues.

Steve

[Duke W.]

Re: Alignment Specs ?

"Toe 1/32 " in Degrees ? "

Read post #6 again.

BTW, its CASTER, not castor.

Duke

[Jack P.]

Re: Alignment Specs ?

Must be a memory from childhood (castor oil )

Jack

[Jack P.]

Re: Alignment Specs ?

Most likely from hitting 59th street bridge in NYC back in 1972 at 4AM. Drove the car home in reverse on the LIE. New springs front and back 7 years ago.

jack

[Steve G.]

Re: Alignment Specs ?

Given the experience I've had with replacement springs, I would still measure the ride height. If it measures up okay I would spend the few hundred bucks to have the frame straightened and correct the issue.

Just dealing with a brand new spring on a 69 that puts the car easily 2 inches too high in the rear. The brand new rear coil springs on my 67 442 have it an inch and a half too high. New definitely doesn't mean correct.

Steve

[Jack P.]

Re: Alignment Specs ?

Given the experience I've had with replacement springs, I would still measure the ride height. If it measures up okay I would spend the few hundred bucks to have the frame straightened and correct the issue.

Just dealing with a brand new spring on a 69 that puts the car easily 2 inches too high in the rear. The brand new rear coil springs on my 67 442 have it an inch and a half too high. New definitely doesn't mean correct.

Steve

Hi Steve,

my my rear is about an inch too high and with the old ones it was an inch too low. I just want to get the toe and camber on spec with all the new rear end, bushings , rods and bolts now settled at 1,000 miles. If I can gain a bit of caster, great, but the car has steered straight with minimum specs.

My my tires have gone 30,000 to 40,000 miles in the last 5 years, two sets with no abnormal wear. After some 45 years my body and the car's body are in sync, I would hate to move things around....lol

So I will show up with new shims an nuts , and tell them 0* camber 1/32 toe 1.++ on caster if possible

Rear -.5 and 1/32 in toe

One more item done in prep for going to Carlisle this year for the first time. I want to spend 14 days on the road visiting 30 + year owners from my 2010 48 state tour, and any owners that want me to stop by to document their cars as part of my research on common owner bonds and personalities . More later with an official " Car is Packed and Carlisle awaits " post with my route from Maine to Carlisle and back. I hope to make it to Ohio, PA, VT, MA, NH, MD, DC, NY, CT,NJ and maybe Road Island!


thanks for all the comments and advice


Jack aka The Corvette Vagabond

You can view NCRS members and pictures of their cars, who hosted me on the 2010 48 state trip at my site

https://www.corvettevagabond.com

[Mark E.]

Re: Alignment Specs ?

Here's the Dick Gulstrand alignment specs I mentioned earlier. Compared to the specs in the FSM, the C2/C3 "touring" spec recommends about the same caster, a bit less toe-in, but NEGATIVE front camber (-1/4 to -1/2 deg) instead of the FSM's POSITIVE camber (+3/4 deg).

I'm interested in feedback from those of you in the know... How would negative vs. positive front camber affect handling and feel? For a street C2/C3, what has worked well for you?

EDIT: I'm looking at a 1970 factory service manual (that says 1969 Corvette on the cover)... maybe other model years have differing FSM alignment specs?

Guldstrand Alignment Specs.jpg