like said , need some different angle pix of under car CROSS brace.

sounds like Doug could help, or ANYONE else.

Ron

 

are we talking about an additional brace added onto the car?

 

It was added onto convertibles starting in 1993 MY. I couldn't find a picture of it online.

 

I bought one from a '96 and had it retrofitted onto my '92. It wasn't straight forward. The rear of the brace connected to the jacking points nicely.....



...... but the front attachment was a lot more difficult. Basically my mechanic had to cut pieces out of the front cross member, then attach fitting points, then weld them back in....



Here is one for sale on Craigslist so you can see what it looks like... Strut brace / X brace for Jaguar XJS Convertible

It does make a difference to the car and I'm glad I did it. I'm looking for the rear brace now but they seem to be more difficult to find.

One other point is that it does reduce the already bad ground clearance further..... the bottom of my brace is polished to a beautiful shine because it spends a lot of its time in contact with the tarmac :-)

 

That brace doesn't look terribly sturdy, it looks as if it would just flex?

 

I was thinking the same thing until I actually got my hands on one. It may not look very substantial but it is pretty stiff and it's also pretty heavy. It definitely made a difference, even her indoors noticed!

 

I have some pics somewhere of the prototype underbody X struts and body somewhere which I'll try to post. I hope from photobucket to here will work.

I designed these back in about 1990. I was a freelance designer brought in to a contract design shop in the UK who got the contract to stiffen the body and had no idea how to do it. I was introduced to Jaguar as one of their staff.

Jaguar were worried by the improved stiffness of the Merc 500SL. Karmann had done some stiffening some time before by putting tubes in the sills but this was like bridge engineering and added a lot of weight. Jag wanted to do the same as the Merc but I suggested it would not work and suggested the X struts. Cutting a long story down, I got a BIW and designed and built the struts. Unknown to me TWR had the same contract. Mine were 5 times stiffer than TWR! I was supposed to introduce them into the production line but as its was such a successful design they did it in a model year change.

I was then kicked out by the jobshop. They got the acclaim by posting pics of a CAE body using their software to make the improvements. It was actually done without their software, just pencil and paper by me. I was at a meeting with the chief body & chassis engineer when it was quoted as "the most effective change ever made to a Jaguar" and rated 9 out of 10 when the norm was 4-5.

I hope I get a prompt to remind me to find the pics.

 

thanks for the info, so typical,the real brains never gets the credit for good design improvments,
like John Lennon said, WE THE PEOPLE ARE THE VICTIMS OF THE INSANE.

thanks again;ron

 

gotta add this; my RHD 78 XJS was last plated in Kent UK, 1986, papers in glove box when i got it off the boat!

 

here is a sketch of the underbody with the proposed struts in place. This was drawn to show the production people what it was about and to discuss how they would fit it.


here are 4 of many pics. the body is hanging and an accelerometer is placed touching the body which exercises a vibration and then this can be translated into a torsional stiffness model.

One of the constraints on the design was because of ground clearance. They were going to lower the body quite a lot but had reports from Australia of bottoming out. I had to flatten the tubes locally to increase the ground clearance and the body was not dropped so much.

They made a vast difference to torsional stiffness. I drove a convertible XJS around the millbrook test track and over the pave. You could not hold the steering wheel. The A post shook terribly. After fitting the wheel was static as were the A posts. I would recommend their fitment as has been done but be aware that reinforcing parts were added so just welding new brackets on to the rear may overstress some panels and cause tears.

Also shown are some of the prototype parts of the front struts and brackets. These are probably not like the production parts as i developed the parts further after testing.

The concept was then adopted for the Aston Martin (Volante?). And I think the XK8 convertible? Can you confirm this? Astons were then owned by Ford as were Jaguar.

I dont currently own a Jag but want to buy an XK8 convertible when I can afford it. Trying to sell my 2007 Bavaria 37ft sailboat to finance it.

 

Anyone happen to have a better picture of the rear under body brace for a 93-95 V12 convertible??

 

Search for Harvey Bailey Engineering they made a cross member for the xjs convertible before Jag made one

 

Old thread but looking to retrofit bracing to my '92. Sarc - "The rear of the brace connected to the jacking points nicely". How did you change the studs over to the threaded screws at the jacking point?

Thanks.

 

I need to look under mine...

 

Don't bother ......'92 didn't have them.

 

I need to locate them and buy them then...

It seems like a worth while upgrade...

 

I'd still like to know how Sarc replaced the jacking point studs on his '92 with the later studs that screw in.

 

I read a magazine article about retro fitting these, Jaguar world l believe it was. It put me off doing it because of the chances of the under body panels being deformed and splitting because of the forces involved when driving.
I have been trying to find the article on line . . . . .

 

The article you are referring to was in Dec 2011 Practical Jaguar. I have a pdf or that article.It is specifically on fitting the Harvey Bailey kit to the earlier cars.

 

Heres a pic of an HBE rear one.


If you have that PDF file could you email it to me ?