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for Improved Handling
David A. Hueppchen
Here is a little general info on front end alignment for performance with high performance shocks, springs and sway bars. I have gathered this over the past many years working on, driving, racing and still learning about Amazons and 1800s.
The Amazon (122 to the nomenclature-deprived) was designed in the 1950s. These cars used bias ply 5.90x15 tires on 4" wheels. The 1800 was designed in the late '50s using as many parts from the Amazon as possible. The 1800 was shod with 165x15 radials in the relatively early days of radial tires (bear this in mind when thinking of 7" wide wheels and wide, low, sticky tires).
Tire technology has come so far since then, it boggles my mind. I lap Road America faster in my mildly modified 1800E than Phil Hill did when he won the first race there in a Ferrari. I'd like more credit, but actually it's pretty much all in the tires.
It was with this old tire technology, combined with an "understeer is safe" attitude, that Volvo recommended 0 to +1/2 degree camber. Everything in more modern print relating to performance radials calls for negative camber or more negative camber (especially when using racing radials).
Changing an equal number of shims on each bolt on an upper A arm only changes the camber, not the caster.
Regardless of the handling goals you may have, I would suggest -1/4 to -1/2 degree camber. If you go to the -1/2 degree, you will have very little increased wear on the inside of the tread and much better cornering.
An increase in high speed stability will start at about 1/2 degree positive caster. Depending on steering wheel size and how many parking maneuvers you do, you may want to go as much as 1 degree. The more caster you put in, the better the stability at speed, but also the heavier low speed steering gets.
Another old Volvo spec I would not like to drive with is setting toe in at 0-5/32". The 5/32" is too much. I prefer close to 0"; a very little out or in. Other factors have an effect on my choice. Some toe out will increase the speed at which the car turns into a corner. As with all other settings, an exact setting recommendation can not be given. Driver style and preference, and changes in the suspension geometry during bump or lean will all determine what set up is best. On-track testing and tire temperature readings can be used to find the optimum settings.
Always set toe last after caster and camber changes. I spent the better part of a day twenty years ago in a little, very rural county park, testing how much difference very slight changes in toe made on a turbo Datsun 510 pro rally car. 32nds of an inch make a difference!
After having what could have been catastophic failures, I studied the 1800E racecar's front suspension on and off for most of two years. Something I learned is: We're putting a lot more force on this stuff than it was designed for. The metal in the shock tower that the upper A arm bolts thread into is very soft. This is not from studying one crossmember, but many. We trashed some on the car; we tested different bolts and sizes in others. Since we found the "cure," we have drilled and tapped two other 1800 crossmembers for 1/2" fine aircraft bolts in addition to the crossmember that's on the car now. The Amazon racecar will likely get this upgrade the next time the motor is out.
There seems to be some misunderstanding at alignment shops and in some of the aftermarket manuals about how caster should be adjusted in these cars. The factory book and I agree: Caster should be adjusted by tipping the crossmember by removing or adding shims. Raising or lowering the front of the crossmember moves the upper ball joint in relation to the lower, changing the caster (loosen the rear crossmember bolts when adjusting this).
If your alignment shop does not know this, tell them! It is highly NOT recommended to change the caster by shimming the upper A arm bolts unevenly. Anything more than a slight difference will, due to the tight fit of the bolts in the dogbone (the part with the bushings), result in the bolts bending twice with each revolution of tightening. No fastener should be torqued and bent at the same time. I see bending and torquing suspension fasteners as very dangerous. If you want to do that with manifold studs, I don't care.
To go in the direction of positive caster, remove shims from the front of the crossmember. I only add or subtract an equal amount of shims on each side of the car. If I find there is a different amount of shims on one side vs the other, I maintain the difference. Either someone before me knew what they were doing, or they didn't and bent something; I'm not going to try to straighten it unless there is an alignment problem.
It is often difficult to tell if the lower ball joints are worn. Often dirt, rust, hard old grease and bits of metal take up the free play from wear. Then, the ball and socket may be worn out and not display it when checking. Worn ball joints can come apart when driving. If in doubt, replace them with new.
Drive as fast as you like, but drive safe.
Diagrams adapted from How To Make Your Car Handle by Fred Puhn