Afternoon all, my 89 convertible is making me wonder if the suspension is too low at the front. The front measures 625 mm to the middle of the wheelarch. The rear measures 650 to the same place . About an inch of difference. The crossmember measures only about 4 inches off the ground. Kirby says about 5. Some once again an inch out? I rebuilt front and rear suspensions with standard shockers(boge) . Could I have got something assembled wrong? Tyres are just some scrappers for storage but have plenty of air in. Rear cubby box is out of the car at moment so that might add a little weight towards the rear. Are these cars meant to be this low? Thanks for any help

 

I don't think the shocks will affect the ride height, that's going to be springs most likely. If they're old and worn out they sag.

 

If you have a Jaguar ROM it should give a ride height specification...which typically includes an allowable "+/-" range. Four inches at the crossmember does sound a bit low, though. What's the measurement at the rear, at the tie plate under the differential?

Does the car have a visible rake? If so, that alone tells a story....as Jaguar intended the cars to have a level stance.

Are the front/rear tires the same size? Check that before getting too far into the weeds

Cheers
DD

 

In the old days, no, shocks wouldn't change ride height. But the high pressure gas shocks that are ubiquitous these days can lift the car a bit. It really doesn't take much pressure. Put four fingers under the bumper and you can lift the body of the car a bit by just exerting a little upward pull with your hand/arm strength.

Cheers
DD

 

Brinny
The tops of the front tyres should be exactly level with the top of the wheelarch. If yours are lower, you need to add two or three packers.

 

Thanks

 

I've had another quick look this afternoon and all the tyres are the same profile so no joy there. Looks a bit low in the photos but its hard to tell. I don't have a rom with the measurements. Is there any way to calculate how many packers Greg? Or would I be better fitting new springs? I've still to refit the cubby box in the back so I don't know if that might help level the car up.


any more thoughts ? I know pictures can be deceiving!

 

Brinny
Hard to tell from the photos, as they are not at eye level to the top of the tyre, but it looks Ok to me. In theory a packer will raise the car about double the packer's thickness, but if it is low, put in two or you will not notice the difference.
I doubt you need new springs, and "new" springs are rarely to the same spec as the originals. believe it or not, Jaguar have NO records of the spring specs they used.

 

brinny,

The front looks low to me but as said, pictures can be deceiving and we'd really need to see a clear picture directly from the side of the car on level ground.

If its difficult for you to measure from the bottom of the front subframe to the ground, then measure from the centre of the wheel to the lip of the wheelarch.

Then post that measurement and the tyre size and other owners can do a direct comparison and let you know.

Good luck

Paul

 

Thanks for the help. I will take a better photo and get some measurements. Will I be able to add packers one side at a time without taking the subframe off again?

 

Sure. But you have to remove the springs to put the packers on top of them.

 

That will require tyre size to be correct. In my opinion, best way to measure it is dimension from hub centre to wheel arch as that will take tyre size out of the equation. I cannot help with my own measurements as I’m far from home.

 

I've had another look and its hard to tell but I think maybe the front is a tad low.


its difficult to get an eye level perspective. Up a bit looks ok down a bit looks too low. I measured from the centre of the hub to the wheel arch and it was 325mm both sides. The tyres are 235 x 60 x 15. ??

 

Hi Brinny.
Here’s my convertible both sides front.
Rob.

 

Brinny
That is too low, I would bung in 3 packers each side. For me Robbo is a touch high. I believe an XJS should have a slight downward rake to the front. This also improves higher speed aerodynamic performance; as Allan Scott's book explained, getting the spoiler lower to the track without anyone noticing was a big part of what TWR was doing...

 

Thankyou both.3 packers will be going in . I already have 1 in i think. Is 4 ok?

 

Brinny,

I measured my '90 convertible from the Hub Center to Wheel Arch and it's 365mm +/-. Hope that helps.

 

Cheers mac. 325mm on mine is obviously too low. Just ordering some packers

 

is the a guide for the thickness of packer required for an inch of height increase?

 

Sorry should have mentioned I have new 225/60 R15 96W Falken ZE310 tyres fitted. I don’t know if that will make mine look a little high.
Rob.