Rear IRS camber setting

[265bhp]

Evening all

Just double checking I understand the angles in the WSM correctly please

-3/4 +/- 1/2 a degree is negative camber which means the bottom of the face of the splined hub should be sticking out more than the top..?

I ask only as having assembled the unit using old shims in the same way as when it was dissasembled i am getting a positive camber...the bottom of the hub is further inboard than the top...

So before I take driveshafts off I wanted to check as the angles are (curiously) the right values...just the wrong way round...if you see what I mean

Thanks all
Jonathan

[288gto]

Hi Jonathan,

Negative camber would give you wheels further in from the vertical at the top.

The camber needs to be set at the correct ride height. The service manual details this.


Simon

[christopher storey]

I think it is impossible accurately to measure camber using only the hub . In any event, it would not be a measurement at the mid-laden position which is what is required . It is best to put the wheels on and run the car for a mile or two before doing any measurements

[mgcjag]

Hi Jonathan.....is the irs back in the car.....it is possible and far easier to set up if its out.......Steve

[265bhp]

Morning all


Thanks for the feedback


The IRS is sitting on the floor of my garage...as my restoration is many, many, many months from completion..

I was interested to try an initial set up with the IRS assembled but not installed...I can appreciate that the surface area of the hubs is small......so more prone to inaccuracy..but am interested to make an initial measurement

If I understand the principle...I would use 2 of the special drop links..(or some other made to measure similar device) and with the damper/springs loosened from the lower wishbone, measure the camber once I have got the IRS cage level


Would that be correct ?

Regards
Jonathan

[288gto]

Jonathan,

I set mine up out of the car having made the correct length drop links.

I used a digital inclinometer on the face of the hubs. I also found that initially using non locking nuts rather than philidas nuts made stripping and re assembly to add or subtract shims easier. Obviously once all set up replace them with the correct ones.
Set the irs cage up level side to side and front to back.



Simon


Simon

[265bhp]

Hi Simon

That’s exactly what I wished to do....many thanks for that.......I have just drawn CAD versions of the drop links and am getting the model makers here at work to cut me 4 drop links from 6mm acrylic sheet on the CNC machines we have now

Back to the cold garage tonight then..

[JagWaugh]

Hi Simon

That’s exactly what I wished to do....many thanks for that.......I have just drawn CAD versions of the drop links and am getting the model makers here at work to cut me 4 drop links from 6mm acrylic sheet on the CNC machines we have now

Back to the cold garage tonight then..

You can also use a turnbuckle hooked between the outer fulcrum and one of the sandwich mounts. It's easier to do on the bench if you leave the shocks off until you've checked this. If the shocks are out you can do it with a racheting strap, but a turnbuckle makes it easier to get the dimension dead nuts.

[mgcjag]

One thing to bear in mind........and open to debate.......if the car is complete with the IRS installed then even with two large guys sitting on the back of my S2 2+2 there was not enough compression to bring the suspension to the so called mid laden point and fit the links ( or achive the dimensions of the links)......so setting up off or on the car with the links and achieveing the correct camber(as per the manual) will be totally different readings with the car just sitting on the ground.........iv seen plenty of Es that have set up the rear per the manual but when you look from behind it has positive camber...........my point is the car never achives the midladen position created by the links under normal use......your thoughts...... Steve

[288gto]

Unless you've got adjustable ride height rear shocks Steve.

Oh and along with the misconception that I know better than the Jaguar service book I added an extra 1/4 degree of negative camber for good luck as shown on the pic.
What you don't want is any positive camber.

We"ll see.


Simon

[265bhp]

drop links CNC style....

[rswaffie]

I’m just about to do the same. I had to make mine out of some steel rod. Not quite as professional as your cnc versions though! I’ve still got to make the second one. When you’ve finished with the setting, could I borrow them - I’ll pay the postage to and from of course.

[265bhp]

Absolutely, happy to help Richard

Don’t worry about the postage ...let me try them tonight first though...

[rswaffie]

Excellent, many thanks. I'm in no real rush as I'm currently finishing off the front susp/brakes installation and still have the dreaded torsion bars to set up! Let me know when you are done and I'll pm my address.

best regards
Richard.

[Series1 Stu]

I'll be interested to see how the acrylic links stand up to the job. I realise that the springs and dampers won't be fitted but there's still a lot of weight in the driveshaft, hub and wishbone assembly for that thin section of plastic to resist. You'll have to work quickly or they will creep and extend. Interesting experiment though.

I had some laser cut from high grade tool steel to do mine.

Regards

[265bhp]

The acrylic didn’t survive..I had to sand the sharp edges of the small end to get it to pass in through the IRS mounting racket holes......it lasted about a couple of minutes and then snapped....so...tomorrow..plan B...we can cut aluminium at work too....so let’s see how that goes....

[mgcjag]

If you want a cheap simply solution then tie it up with parachute chord or similar useing a slip knot and adjust to correct dimension useing a tape measure.....

[288gto]

Perhaps not the most elegant of tools but this is what I made.

As the IRS was out of the car and the shocks not fitted, I used one of these on both sides in place of a shock absorber and adjusted it until I'd got the correct dimension from the centre of the outer fulcrum to the hole in the IRS mount as per the service book.




Just an alternative approach and something that can be used for the front as well.

Simon

[265bhp]

our model makers just made these for me....4mm aluminium....fingers crossed this will work...we will see this weekend.....either way they are gorgeous looing objects...







Jonathan

[Series1 Stu]

Hi Jonathan

They will definitely be better than the acrylic ones, and they do look good. Again it will be interesting to see how you manage. Gut instinct says they should be okay although I would have made the narrow part a lot wider by taking it straight across tangential between the large and small diameter sections. That's what I did with my version that I had made from tool steel, but I was making sure that it was strong enough to load the suspension on the car.

Have fun with your setting up.

Regards