Projects 1957 Oldsmobile: Jaguar XJ6 IFS/IRS

You are the Man, Steve.

 

Looks good!

 

Not sure how I missed this,but I'm on it now.
Looking forward to it moving forward with your magical touch

 

Got the bottom rails and some of the outer side rails figured out.

 

I've always liked your plan ahead for future projects attitude. As with all projects, exact measurement is critical to get it plumb, straight and square. Go Steve, go!

 

Steve,
I'm glad you are feeling somewhat better after the accident.

 

I just spent the day at a specialist Jag boneyard and it was an interesting exercise. I thought I more or less had a handle on the Jag suspension thing but I guess the handle broke and fell off. So I thought I would share what I learned: one of the biggest PITAs with the Jag IRS inboard disc brakes is if you need to work on them once installed. The 1994-1996 (end of production) model year Jag XJS has the classic Salisbury diff - with Powrlok (posi) but uses the hub carriers of the XJ40 and I think that the XJ hub carriers are good thru 1998. This means that you get the classic four coilover suspension but with solid rotor outboard brakes. This is 61-3/4" hub to hub (same as the XJ6) and has a 3.54 final drive ratio - great for your o/d trans. A very few - and I mean very few of the last - 1996 XJS - not only had the outboard brakes but they are ventilated too.

I was fortunate enough to find a specialty wrecking yard that specializes in Jags and whose owners know their stuff. They have been in business since 1976 and are still going strong. So for less than the cost of one basic aftermarket Pinto - er I mean Mustang II IFS setup, I was able to come home with not one but two complete late low mileage XJS IFS (with power steering rack and sway bar) and IRS units with vented outboard brakes plus the halfshafts, hub carriers and vented rotors with calipers to convert an XJ6 inboard IRS I have to outboard brakes. That's two complete suspensions plus extra parts! Judging by the condition of these units they can be installed and used as is, without the need to replace anything. Everything is tight, the rubber components all look good and the factory paper tags are still on the IRS cages!

I cannot speak highly enough of Rick at Elite Auto Salvage in Sun Valley CA. The parts were thoroughly degreased and cleaned and sold for no more than you would pay for an unknown quantity from an unknown seller at a swap meet. Plus they carry a 90 day warranty and he ships nationwide. So if a Jag is your bag give Rick a call 8am-4.00pm Pacific on 818 767-0445

 

thanks so much for posting this stuff, I've got merc and a jag front waiting to be introduced so awesome to see such an in depth blow by blow from a pro.

Hope it's not out of line to ask but don't spose you'd be willing to make the 3D file with the jag bushings/mount locations mapped out available? (strictly non-profit personal use of course)

 

Spent most of the day measuring and drawing. Pretty close to done, just need to revise the trans mount holes and add a core support crossmember. Cutting parts out soon!

 

It's so pretty.

 

I'm always amazed reading about your work! With the new clip does itt raise the cross member to give you more effective drop vs the stock rails? Loving it! Thanks!

 

I have the IFS set maybe a bit higher in the frame than usual, the owner wants it low.

I am figuring for the 3" of compression travel to get to ride height.

 

Getting the frame rails together.







Sent from my Galaxy Nexus

 

You are so making me want to redo mine.

 

I'm wondering what's so hard about the brake maintenance. The only time it's a pain at all is changing discs, and even that is not so hard if you have access to a lift.

 

Zman when the diff is backed up right close against a gas tank in a fat fendered rod it is not that easy or accessible. This will be the case with my installation which is why I chose to go the outboard brake route. Plus I plan on retaining the cage which also adds to the accessibility conundrum....

 

Can we stop muddying up Steve's thread?

 

steve are those new rails .188? Weasel start a seperate thread they will follow cause your info is great!

 

Okay - fixed it - removed all the offending stuff....

 

good stuff, very interesting read.work is awesome.geter done

 

Good info dude nothing offensive about it!

 

Hmmm Steve, will you be selling the frame rail "Kit" like a welders series to put a Jag into something else?

Looking great, I enjoy watching technology applied to hot rods.

 

I don't think that would work too well. So many variables and so many models of cars and trucks to fit. Plus the lack of skill to pull it off.

The rails are tweaked into position and Brian has been welding and grinding them. Final fitment should happen very soon!

 

Rails are welded and finished. Placing them today and welding them to the frame. Front clip goes on next to create the missing core support crossmember.

 

There are many PITAs with that, I think most Jag shops just drop the cage out of the car to work on the rear brakes.

It was my understanding that almost all XJSes had 2.88 rears, and the 2.88 diff carrier won't accept any shorter gears without a spacer ring. Are you sure about the 3.54 gears?

 

I have to ask, since you're a lot further down this road than I am...when you're starting to lay out a part like that, obviously you start with the dimensions and spacing of the frame stubs and I'd guess you wanted the front crossmember to resemble the stocker and be in the same place and obviously the mounting points and clearances needed for the Jag assembly.

Do you start by laying out planes and reference lines/points from the stubs, the front crossmember, and the Jag crossmember mounting points, then 'connect the dots' with the first rail? Do you start with the top view, or the side view? Do you try to get most of the shape into the sketch, or do you do a big rectangular member then extrude-cut off chunks to make the profile?

I assume the result gets exploded into flattened cut patterns of the folded sheet.

Not looking for trade secrets, just tips

 

Yes - got two of them with outboard brakes from late XJS and one with inboard brakes from an XJ6. Also have an extra carrier with 3.54 and Powrlok and a 56" hub to hub inboard unit.

Steve - just a brief thank you very much for this very informative thread which I am following with great interest and a brief apology to all you Jag lovers that the mods closed my tech thread on Jag suspension. I did ask that it be reopened but the powers that be told me they are 'being hardasses' on non traditional stuff. So feel free to PM me if you like to try and get the thread reopened....

 

Seems tough when the HAMB has over 20 threads on Jag front and rears, including this one.

 

Your thread was as good, and mostly better than many that we have to endure... Do you have any plans to continue the documentation and somehow package the info for dissemination?

.

 

Please do the thread over on Dogfightmag.com