Daze wrote:

NOT FAIR!!!!
you got it easy I had to fabricate up this thing to make my set up "bolt in"

I didn't see a single mounting point in your situation  that couldn't be accommodated by making a simple bracket or two.  What is the wiring harness coming of the diff??  also what is your pinion angle in relation to the plane of the LCA pivots??  on the older units there were a couple of pinion angle options and we discussed them in great detail on past threads debating the best way to get the correct pinion, trans alignment.

Yeah, these IRS units look very user friendly, im suprised more people arn't using them.
the wiring is the ABS sensors, there is also a hall effect speedo sensor up near the diff on the left hand half shaft. I removed all that today.
I plan to match the pinion angle of the trans. my engine sits on my own fabricated mounts and is arund 2deg down, so ill run the irs @ 2deg up. How the lower arm anlgle will end up im not sure, but im not really concerned if the plane of the lower arms is not parallel with the ground, unless of course it end up being a ridiculous angle....ill cross that bridge when i come to it, but the great thing with this irs, pinion angle on the diff will be extremly easy too adjust by making adjustable rods for the rear mounts, the front mounts have plenty of give so theres a few degrees of flex there...

Keep in mind, mine wont be a true bolt in, i need to remove all my old watts link bracketry, so i wont be able to revert back to standard suspenson easily like your system

Last edited by KLR250 (5/27/2011 11:05 pm)

Aw the great debate about pinion angle.  My bet is 6º  I say that because that is the angle Jaguar used on some previous models  As far as how you should deal with it, this has been a hot topic.  Their are basically two camps, one says get the suspension traveling vertically and let the pinion angle be what it is and others say get the pinion angle correct and let the suspension travel angle be what it is.  I am of the mind that the suspension needs to travel as vertical as possible.  The pinion angle is important but because of the differential being in a fixed location you can get away with a slight mismatch between the differential and transmission.   What angle is your transmission at???

they ran the suspension at 0º  the suspension traveled vertically any angles at the pinion where to correctly align it to the transmission.

Daze wrote:

they ran the suspension at 0º  the suspension traveled vertically any angles at the pinion where to correctly align it to the transmission.

okay, but to make sure im being clear, with the diff pinion set to 0 my arm lean down toowards the rear on at least a 6 deg angle, it looks closer to 8 or 10 though, so as the suspension moves up the hub travels rearwards a little

if i set the arms to 0 the pinion would be facing down the said amount of degrees, which obviously is not an option

so your saying setting the pinion on the older units to 0deg had the arms level?

just out of interest, heres a picture of an XJ40, now bear in mind its harder to judge because of the angle the picture is taken, but you can clealy see the angle of the lower arm pivot bolt, it angles down towards the back of the car...once i get thses brackets done ill post some more pics

Last edited by KLR250 (6/14/2011 2:39 pm)

KLR250, the pinion needs to be parallel to your trans output shaft first off. As far as the control arm angle, exaggerate it in your minds eye, say 45 degrees. Now imagine the effects.
http://www.hotrodhotline.com/md/html/drive_shaft_harmonics.php

Last edited by Ralphy (6/14/2011 3:25 pm)

Finished both front mounts tonight which is good

Drivers side



Passenger side



Off to a machine shop to get some mounting spigots machined up and Ill weld them onto my brackets, then i can start on the rear mounts finally.

Sorry about these crappy quality pics, my camera is broken and im using the wifes iphone

Last edited by KLR250 (6/16/2011 5:25 am)

ill set it to 1.5deg up to match my gearbox This is where i have set my brackets (gearbox can easily be shimmed up, lots of room), not to concerned about the angle of the lower arms, as this is how the XJ40 was, so i pressume the jag engineers had a good reason to do this. I need to find an XJ40 and find out where they set the pinion, but either way im not to concerned, the bush's 0n the irs are very flexable, so i can fine tune the pinion angle by making the rear mounting rods adjustable

Last edited by KLR250 (6/16/2011 2:31 pm)

so are you compensating and mounting it in the center of the wheel well at ride height???  that way it will move forward as the suspension extends and back as the suspension compresses???

well, after a few hours of drilling cutting, getting covered in grinding sparks I have the watts link crap removed, what a nasty job that was









and heres whats left....good riddance to it



put the IRS back in to check how the rear mounting struts will sit





the drivers side rail opens up to the spare wheel tub, so it looks like ill need to shorten that rod 2". I think ill shorten both rods, as i want them to looks the same. Ill make the rods adjustable,
this way i can adjust my pinion angle easily



Out of interest, this pic shows just how well things line up. I used an old watts link rod to see how the lower spring mount on the jag IRS lines up with the spring tower





In this pic you will see where ive marked out this peice in the middle, its close to touching the diff, so it needs a minor trim and a bit of sheet will be welded in





and a few random pics for good measure

Last edited by KLR250 (6/18/2011 7:34 pm)

looks like it is coming together.  have you made any more progress on the install??

Ive been really slack lately, like really really slack!

anyways, made my adjustable mounting rods for the rear supports omn the jag IRS. Ive ditched the factory jag rods and made some new ones utilising some XF watts link rods. I needed the rods to be shorter than the jag ones, just because of the differnt shape of the floor and how far up inside the car i have the IRS assembly. Cutting down watts link rods made a bit of sence, there thicker walled, bigger in diameter, buysh's are available in nolathane, and there free. First i cut the rods down and tapped a 14 x 1.5mm thread into them, I wanted the thread resonably fine for better adjustment, and 14 x 1.5mm was as fine as i had. Inital plan was to buy some grade 8 all thread, but it doesnt seem to exist, so i bought some long grade 8 bolts, cut the heads of and got the threads cut on the lathe, so now ill be able to easily adjust pinion angle on the diff, which makes it easy to fine tune and match the pinion angle to the transmission.






Here you can see the jag tube diamter vs the XF watts link



all done, Jag vs New rod




and this is how i plan to set them up, the RHS is just some old "I used a word I shouldn't have" i had lying around, but this is the size ill use, it will tuck up a bit higher and have the required bracketry welded on to secure the rods.









The twin exhausts will pass in between the rods and diff centre

hmmmmm camber



Currently im working on the spare lower control arms I have, Im actually shifting the hub mounting brackets forward, as im not happy with the wheel position, and i dont want to shift the whole assembly forward. as it stands i have room for the exhausts to pass over and id rather not hack the floor for room, so rather than shift the entire assembly forward im just shifting the hubs forward on the lower arms. This involves cutting of the brackets, jigging them up so the brackets sit where i want and re-welding them....not to hard, and really, if you had to do this conversion most people would move the IRS assembly forward, but i like I said, i like the room for the exhausts.

anyways, ill get some pics of that later

Daze wrote:

well you make the phrase "Ive been really slack lately, like really really slack!" look like you got a lot done.  I think its all the pictures.  That is one of my favorite parts of your post there so visual that a person can really see what you are working on.  It may not seam like a lot of work but we all know that those "little" jobs take a lot of time so the more of those you can nock out the better can't weight to see more, thanks for posting.

Thankyou Daze, good when someone else appreciates the effort involved, its all these little niggly jobs that take so long! Im a pretty simple person, not good at working things out on paper, I kind of have to put things together and rework where neccasary lol

Enough about your life Day!

Daze wrote:

KLR250 wrote:

Im a pretty simple person, not good at working things out on paper, I kind of have to put things together and rework where neccasary lol

They are both excellent approaches.  There is something to be said for having a plan on paper first so you have an idea where you are going BUT in most cases the best laid plans still fall short and you have to rework on the fly. 

Last edited by Ralphy (8/30/2011 8:40 am)

hey KLR250 how is the project going we have not gotten an update in a few months