C2 & C3 frame set-up for wheel alignment

[Greg L.]

As I assemble my chassis I was thinking that I should try and do a wheel alignment at the same time. A friend of mine will lend me his home alignment tooling that he uses for road racing so if not bang on I should at least be able to get it really close.

I have the frame level left to right but should the frame also be level front to rear or is there a rake to it?

I'll be doing this alignment without the springs so that I can have each wheel in the proper geometric position to simulate the correct ride height.

Yes I know this is the long and hard way to do it but I just don't want anyone besides me leaning over my freshly painted body after I get it back on the frame.

[Kent K.]

Re: C2 & C3 frame set-up for wheel alignment

FWIW - my understanding is that any alignment should notr be attempted until after full loading on the suspension. If done before and then loading is applied, all settings are off.
Regards, Kent

[Greg L.]

Re: C2 & C3 frame set-up for wheel alignment

Yes Kent I think you might be right about that..can't say for sure because I've never tried it before and after.

All I'm trying to do is get REALLY close to the ballpark so that if it does need to be tweeked after it's all back together the guy won't be spending too much time under my hood....or worse, over my fenders.

[Wayne W.]

Re: C2 & C3 frame set-up for wheel alignment

FWIW - my understanding is that any alignment should notr be attempted until after full loading on the suspension. If done before and then loading is applied, all settings are off.
Regards, Kent

If you have the wheels at the proper height, you should be able to do a good alignment. There is some forward rake, not much.

[Rob S.]

Re: C2 & C3 frame set-up for wheel alignment

Greg,
You can NOT alignment the car unless the car is at ride height, with the full weight of the car loading the chassis. Not only will the camber's change but the toe's will also, Both front and rear.

[Wayne W.]

Re: C2 & C3 frame set-up for wheel alignment

Greg,
You can NOT alignment the car unless the car is at ride height, with the full weight of the car loading the chassis. Not only will the camber's change but the toe's will also, Both front and rear.

He did say w/o springs. There is no reason he cant achieve a relatively good alignment that way. At least good enough until he gets it finished and then get it checked.

[Rob S.]

Re: C2 & C3 frame set-up for wheel alignment

Unless you know the exact ride height of the car, you can only get it simi close, springs in or out.

[Michael H.]

Re: C2 & C3 frame set-up for wheel alignment

As I assemble my chassis I was thinking that I should try and do a wheel alignment at the same time.

Greg,

As Rob mentioned, unless the exact ride height of the completed vehicle is known, it's not possible to accurately align either the front or rear. A small change in ride height, front or rear, will change all of the alignment settings.
You can set the suspension checking angles and set the chassis height to these published dimensions but it's unlikely that the complete vehicle will sit at this same height.
If you have a new rear spring, or even new liners in an original spring, the ride height will be different than it was before you disassembled the car.
Fortunately, the one dimension/setting that would probably change the least during suspension travel at near design ride height is also the most difficult to adjust with the body reinstalled and that dim is the rear toe setting. If you can get that dim set, it's possible it will still be accurate when the car is assembled.
The rest of the adjustments, both front and rear, are easily accessable with the body installed.

[Duke W.]

Re: C2 & C3 frame set-up for wheel alignment

Since the springs are not installed/connected it should be relatively easy to set the front and rear suspensions at the proper Z and D dimensions as stated in the appropriate CSM and AIM. These are the correct front and rear ride heights. I hope everyone now understands this. Even when the front springs are installed there are ways to compress the front suspension to the correct ride height, and it's easy to disconnect the rear spring.

Assuming the frame is on jackstands from a relatively flat surface like a garage slab, use an inclinometer and shims as required to level the frame rails both laterally and along the centerline. There is no "rake".

Measure the exact mid points of the cross members then run a string below your centerline and attach bobs as required to get the string at the correct level to measure rear toe in. You want 1/32" on each side as measured from your centerline assuming you will be using radial tires.

The steering wheel should end up centered if the tie rods are at equal length at your final front toe setting and any required minor adjustment can be made when the car is back on the road.

Duke

[Michael H.]

Re: C2 & C3 frame set-up for wheel alignment

Since the springs are not installed/connected it should be relatively easy to set the front and rear suspensions at the proper Z and D dimensions as stated in the appropriate CSM and AIM. These are the correct front and rear ride heights.

We tried setting front/rear specs on a rolling chassis on two different ocasions. On both, the dimensions were not the same after the car was completely assembled. The ride height was not the same as the dimension shown in the book (often the case) and that changed the camber of both front and rear wheels.
The toe setting in the rear was still within specs but it too changed slightly.
Also, there is some degree of dimension change when the full weight of the car is actually by the suspension components. I suppose there is some degree of bushing flex/compression?

Interesting that, while aligning the front of a C4, the hood must be closed when checking the dimensions. Supposedly, when the hood is open, the ride height is affected slightly by the change in weight distribution and ride height. It doesn't take much of a change in ride height dimensions to have an effect on alignment specs.

[Duke W.]

Re: C2 & C3 frame set-up for wheel alignment

If the car has correct springs the ride height should be within specified tolerance of the Z and D dimensions, and the car has to be "rolled out" a considerable distance to acheive proper ride height after being dropped to the ground from jackstands.

Given the weight of a C4 hood I can understand that its position might make a difference.

Duke