Hi, Im hoping someone can help me

We have a XJS (series 2 or 3) IFS setup in our classic car (39 chev) and we are needing some more caster. Does anyone know of aftermarket upper control arms which could achieve this or any other method. All shims are on the front side and we are still needing more

Thanks

 

Off the top of my head the only thing you could do is to have a new inner top wishbone fulcrum pin machined up out of top notch tool steel made so that the front part of the pin that holds the bearing for the rearmost arm of the wishbone is made half an inch longer. Then use spacers to push that leg of the wishbone and its bearing rearwards a bit on its fulcrum, while adding the equivalent amount of packing to the shims on the front side of the balljoint.
What this would do for the strength and integrity of the whole assembly, goodness knows.

 

Are you sure the IFS came from an XJS?

Mentioning "Series 2 or 3" suggests a sedan (XJ6/XJ12/VDP) rather than the XJS. The sedans had (at least) two different build configurations with respect to upper control arms, with some (V12 cars and later Series III 6-cylinder cars) designed to give more caster than others. So, your fix might be as simple as getting different control arms.

Verifying what you already have would be the first step

Cheers
DD

 

How did you mount the IFS. ? May need to re-afix it. You can move some of the shims to the front of the upper ball joint? Have you already done that?

On the Jag I have simply add a 1/4 inch spacer to the flat side of the rear subframe Mount along with longer bolts. That leans the whole IRS back in such a way where you get more caster.

As for new control arms nothing off the shelf. Custom units would need to be welded up.