Alignment problem
Thread Starter
4th Gear
Joined: Jan 2010
Posts: 4
Likes: 0
From: Copper Canyon Texas
Alignment problem
I'm new to the forum and would like to ask if anyone can help me with a front end alignment issue with my '59. This car will be a dedicated vintage race car and is finished except for setup. In setting front alignment I find that, even with the adjusters pulling the upper spindle supports as far back as possible, I can only get 2 degrees of positive caster on the left side and 1.3 degrees on the right side. Camber can go to 1.2 degrees negative on the left, but only .5 negative on the right side. I would like to have at least 3-4 degrees of caster and 1-1.5 degrees negative camber.
All bushings and shafts are new and bearings are adjusted properly. The factory shim is installed between the frame and suspension support. Anybody know of a way I can get some more positive caster and negative camber?
All bushings and shafts are new and bearings are adjusted properly. The factory shim is installed between the frame and suspension support. Anybody know of a way I can get some more positive caster and negative camber?
Race Director
Joined: Feb 2007
Posts: 15,422
Likes: 8,873
From: northern california
C2 of Year Finalist (track prepared) 2019
For additional caster, I'd add a second shim between the crossmember and the frame.
Some vintage racing organizations frown on changes to suspension geometry. You might want to check the rules before you seriously consider either of my suggestions.
Got any pictures of your vintage racer you can post?
Jim
Thread Starter
4th Gear
Joined: Jan 2010
Posts: 4
Likes: 0
From: Copper Canyon Texas
Thanks for your reply. I'm going to order some of the tapered shims and see if that gets the caster in line. The front end is just slightly too low now, so the extra shim should help that somewhat. Also looks like I may have to re-shim the radiator support.
I looked at moving the lower control arm outboard as you suggested, and it appears that it wouldn't be too difficult. However, you are correct, moving suspension pickup points is usually not allowed in production cars by most vintage racing associations.
I may go on Monday and see if I can get a new upper-outer shaft machined that has a bigger eccentric in it so I can get more camber adjustment. Any other suggestions are welcome.
I have no pictures yet since the car has been finished for only about a week. When I get this alignment issue solved I'll get it outside and shoot some pictures.
I looked at moving the lower control arm outboard as you suggested, and it appears that it wouldn't be too difficult. However, you are correct, moving suspension pickup points is usually not allowed in production cars by most vintage racing associations.
I may go on Monday and see if I can get a new upper-outer shaft machined that has a bigger eccentric in it so I can get more camber adjustment. Any other suggestions are welcome.
I have no pictures yet since the car has been finished for only about a week. When I get this alignment issue solved I'll get it outside and shoot some pictures.
Melting Slicks
Joined: Jun 2006
Posts: 2,660
Likes: 7
From: DFW
Moog makes an offset upper control arm shaft that will give you some more adjustment too. It is a collision repair part that is sold by the Corvette vendors as a "trick part" ($). Let me know if you need a Moog part number.
Sounds like you might be running the Gulstrand metal control arm bushings? They will work just fine with the Moog part (did it on my 69 race car)
Harry
EDIT: I see Bill's photo and realize its a C-1... sorry for the distraction...
Sounds like you might be running the Gulstrand metal control arm bushings? They will work just fine with the Moog part (did it on my 69 race car)
Harry
EDIT: I see Bill's photo and realize its a C-1... sorry for the distraction...
Last edited by 66since71; Jan 24, 2010 at 02:47 PM.
Race Director
Joined: Feb 2007
Posts: 15,422
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From: northern california
C2 of Year Finalist (track prepared) 2019
Jim
Drifting
Joined: Oct 2008
Posts: 1,936
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From: Rochester Hills Michigan
I did this in 1977, so I am assuming I bottomed the forward nut on the shaft and then backed it out just enough to fully engage the control arm as I threaded it into the arm?
I'm sure I ran the suspension through its travel without the spring installed to check for binding (I always do this).
Here's a current picture. Excuse the condition. The car's been sitting for decades (restoration in the planning stage).
Bill
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Thread Starter
4th Gear
Joined: Jan 2010
Posts: 4
Likes: 0
From: Copper Canyon Texas
I re-indexed the upper arms as far back as I could. This is easy to accomplish by removing the bushings, moving the arm back, and re-starting the bushings into the arm and shaft in the new location. After doing this I am getting 2.5 degrees of caster and 1.2 degrees of negative camber on both sides. Still not enough caster, so I have ordered a couple of the shims. Hope that works.
Drifting
Joined: Oct 2008
Posts: 1,936
Likes: 92
From: Rochester Hills Michigan
I re-indexed the upper arms as far back as I could. This is easy to accomplish by removing the bushings, moving the arm back, and re-starting the bushings into the arm and shaft in the new location. After doing this I am getting 2.5 degrees of caster and 1.2 degrees of negative camber on both sides. Still not enough caster, so I have ordered a couple of the shims. Hope that works.
I remember my car (see pic. above) had a strong tendency to go to full lock when backing up. I had to hold the wheel firmly to keep the front wheels pointed straight ahead. Not sure what is causing that (KPI?)...2 degrees of caster is not a lot.
Race Director
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From: Mustang OK
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Years ago, the owner of the alignment shop that I use (THE ONLY ONE IN OKLA CITY I TRUST!!!) taught me a little trick to gain (or loose) caster.
On the LOWER- INNER shafts, loosen all 4 bolts. Add alignment shims under the REAR of the shaft. Tighten bolts. TOOOOOOOOO EASY to add caster by this method. We did this to the 56. I don't have any pictures of this, but if anyone wants to see, I can take pictures tonight.
Tom Parsons
On the LOWER- INNER shafts, loosen all 4 bolts. Add alignment shims under the REAR of the shaft. Tighten bolts. TOOOOOOOOO EASY to add caster by this method. We did this to the 56. I don't have any pictures of this, but if anyone wants to see, I can take pictures tonight.
Tom Parsons