bushing education needed

[pigman]

Hello,
I am in need of a quick direction suggestion. I see upper control arm bushings / regular and another option of additional positive.
after speaking with an alignment tech at a local shop over the phone I am not sure if the answer fully satisfies me....here it is.

I have a '66 valiant with torsion bars, are you familiar with this.."Yes" he said. OK, I see two different bushing options to get, knowing the original tire was a bias ply, and now I am running radials, how would the difference if any would the tires come into play with either choice of bushing..? "None, order the originals"...he said

OK..so why do they make the eccentric set..? I am pretty handy and plan on installing these myself to save some dough, don't want to put it on a rack and have him say.. you need more positive.
I am trying to get my repairs done before the alignment. Don't want to screw around.

any information would certainly be helpful..Thanks , Pig man

 

[67Dart273]

Well he's full of crap about alignment settings, anyway. It MIGHT be that you can get "enough" with stock bushings, but there is a reason these are made. Moog, until Chneseo came along, was always a respected supplier of chassis parts. One of the best

It is an accepted fact that modern radials like CAMBER settings which point the tops of the tires IN (negative camber) while older bias settings were the opposite, camber being the tops of the tires pointed OUT. (positive camber)

Also, you want more CASTER with radials.

Do a search here, there are lots of threads on this subject

http://www.forabodiesonly.com/mopar/showthread.php?t=226484

http://www.forabodiesonly.com/mopar/showthread.php?t=231627

http://www.forabodiesonly.com/mopar/showthread.php?t=183214

http://www.forabodiesonly.com/mopar/showthread.php?t=227050

Here's a good read, and seems to be right on the money. The "skosh" chart down the page shows updated alignment for modern tires.

http://www.allpar.com/history/mopar/front-end-alignment.html

 

[KosmicKuda]

Hello,

OK..so why do they make the eccentric set..? I am pretty handy and plan on installing these myself to save some dough, don't want to put it on a rack and have him say.. you need more positive.
I am trying to get my repairs done before the alignment. Don't want to screw around.

any information would certainly be helpful..Thanks , Pig man

I would assume that Moog first made the offset bushings to give additional alignment adjustment for cars that couldn't be brought into spec. You know cars that were damaged in wrecks, old age, etc. These parts were in the category of "problem solvers"


Personally, I would not build a vintage Mopar without them...period. The idea is to install one pair of bushings in each upper control arm arranging them to get maximum caster. If you can find Tom Condran's book on building Mopar suspensions with mostly factory parts, that would be the first step.

I rebuilt the front end in my 68 using the offset bushings, Moog rubber lower bushings, Moog strut rod bushings, and replaced other worn parts as needed. Used a 1/2" threaded rod w/ short pieces of exhaust tubing to remove and replace the upper bushings. Dropped the LCA's off at a shop and they installed the lowers. Only used poly in the sway-bar and in the rear springs. I use Moog parts because I trust them. If you buy a universal kit you really don't know what you're going to get. Anyway I gave the alignment guy MY specs and he did what I wanted. 2* positive caster, 1/2* negative camber, and 1/16" toe-in. Do NOT let them align the car using the factory settings and both sides of the car use identical numbers. Also have .920 T-bars, HD rear springs and 16:1 manual steering.

So the result is a car that tracks hands-off on the Interstates and it handles pretty well. This is with (4) 215-60x15 radials on 15x7 wheels. There is no darting and floatiness like the old days with bias ply tires and zero or negative caster.

 

[pigman]

I really appreciate your feedback about my bushing dilemma.
I have found an "old school" fella that knows exactly what your talking about with the use of eccentric bushings and tie-rod experience.
I visited him at his shop, took a few people to be directed to this guy, but after speaking with him, I feel very confident that he'll set-up my front end perfectly.
This site is wonderful, with all who participate in helping one another out.
Again.. Thanks so much for the Education.. pig man

 

[pacuda59]

It looks like Pigman got the feedback he was looking for so I'm going to hijack his thread if that's ok.
I'm replacing my front drums with discs this summer and wondering what bushing's, etc. I should be replacing also?

 

[RustyRatRod]

The contact patch of a radial tire stays on the road for a wider camber sweep than that of a bias ply. So, that means that they require more camber (either positive or negative) to get to the same place as a bias ply tire. This is what Del described above and he's right on the money. When I did alignments, 95% or more of my customers cared more about tire wear than handling, so 95% of my alignments had camber between zero and .5* positive, unless the spec was really negative like some sort of sports car. But Del is right. Usually around .5* negative camber is just about right for our cars for decent street handling.

About the offset bushings. The alignment man you spoke with might not be as crazy as he seems. He may be thinking as long as the car has not been wrecked or hit, that is does not need the offset bushings. Not every alignment man is totally familiar with MoPars and their need for more caster, which is the main reason for the offset bushings. Personally, I would rather go with an upgraded upper control arm rather than the offset bushings.

The "thin" side of the offset bushing is just that. THIN. They tend to wear much quicker because there is less rubber on that thin side. Some people may say "I've had them for years, blah blah blah".....and that may be true, but they are probably driving like a little old lady, too. The offset bushings would not be the way I would go if I were planning on keeping the car.

You have to be careful though with too much camber either way, positive or negative with certain brands of tires. Some radials are already rounded on the edges when new. The BF Goodrich Radial TA is a good example, unless they've been redesigned. They cannot stand a lot of negative OR positive camber without wear on the edges. You really have to stay on top of the rotations. Look for a tire that has a really squared off edge on the tread and it will be able to take a little more camber lean. Once they surpass a certain amount of wear on the edge, the wear keeps accelerating and is almost impossible to slow down. Goodyear makes some tires with crisp square edges.

Good handling is not just in the alignment alone. It's a total package.