Technical Jag IRS Info

[fiftyv8]

Can anybody post a list or charts of Jag IRS width specs as has been done for Ford 9" rear ends.
Maybe even related to model ID's also...

[53sled]

http://www.jalopyjournal.com/forum/s...ad.php?t=77729

XKE is a more narrow version than the xj style, most parts interchange 70-86

[Hnstray]

just yesterday there was a resurrected thread on Jag IFS that had a post threin with dimensions of Jag IFS and IRS. The thread was titled something like "Jag IFS into F100".

Also, if you google Jag suspension info there is a lot of info that will turn up there including dimensions.

Ray

[jrblack30]

Here is one but I dont think it uses any 9" gear

[fiftyv8]

Well here is some info I've gathered from your prompts.
I figure by putting it here it will help other searches later.
Flanges are old big Chevy bolt pattern (5x4-3/4").
The Jag XJ rear width is about 61 1/2".
If XJ jag rear is too wide XKE control arms and axles can be used and are approx 4" narrower per side. (fit perfect under a model A)
A stock XKE is 53 1/2 inches wide.
Model width List:
Mk 1, 11 58-59
F - 1422 - 56.88"
R - 1381 - 55.24"

Mk X 62-67
F - 1498 - 59.92"
R - 1498 - 59.92"

S type 64-68
F - 1428 - 57.12"
R - 1403 - 56.12"

XJ6 69-73
F - 1479 - 59.16"
R - 1506 - 60.24"

E type, E type Series II
F - 1295 - 51.8"
R - 1295 - 51.8"

E type Series III 72-73
F - 1403 - 56.12"
R - 1403 - 56.12"

XJ6 Series II 74-82
F - 1505 - 60.2"
R - 1520 - 60.8"


Top of rear should be mounted at 6 degrees for control arm mounts to be level.
Rear locating arms to frame should be level with ground at ride height.

[ThunderRocket]

good info!

[tahn07]

Is this hub to hub or outside of tire to tire, or track width?

[plym49]

Originally Posted by jrblack30

Here is one but I dont think it uses any 9" gear

Done wrong, just like most of them that you see.

You do not use trailing arms with a Jag rear end if the rear is solidly mounted to the frame. You only use trailing arms if the rear is resiliently mounted to the frame using the stock Jag cage. If you really really think you need trainig arms, then the axis must be far forward and on a line that exactly goes thru the axis of the lower fulcrum bearings.

The reason for this is that the stock Jag parts are crazy strong and have NO interference motion. All of the bearings are roller bearings.

The stock Jag trailing arms were mounted in rubber, like the cage, and provided a rear-steering effect when the car went hard around a corner. Thus, the entire cage was able to move around but the rear suspension was solidly no-interference.

If you introduce interference motion into the equation, like by solidly mounting the rear and adding trailing arms that do not pivot on the axis of the lower fulcrum bearings, you are bending and stressing parts and something is gonna break.

If you are putting a Jag rear into a shoebox or other vehicle where you do not see the rear, you are probably better off using the stock Jag cage around the rear. They are really easy to mount (use the stock Jag mounts - they look like motor mounts - something like 8 bolts total) and also the stock Jag trailing arms (rotate the robber 90 degrees for stiffer rear-steer, leave it stock for normal rear-steer).

[LIFESTYLZ]

Originally Posted by jrblack30

Here is one but I dont think it uses any 9" gear

He didn't want anything with 9" gear.

[derbydad276]

the ford IRS adapts pretty easy for for pick ups and might go into cars easy to


http://team321.com/truckirs/truckirs.html

[JEM]

Originally Posted by plym49

Done wrong, just like most of them that you see.

You do not use trailing arms with a Jag rear end if the rear is solidly mounted to the frame. You only use trailing arms if the rear is resiliently mounted to the frame using the stock Jag cage. If you really really think you need trainig arms, then the axis must be far forward and on a line that exactly goes thru the axis of the lower fulcrum bearings.

...and one would note in corroboration of that, when Jag revised the rear suspension and changed the mountings for the XJ40 they got rid of the trailing arms completely. Roll understeer in the later setup is handled in the angles of the lower control arm mounts, not by 'steering' the cage with the trailing arms.

[JEM]

Originally Posted by derbydad276

the ford IRS adapts pretty easy for for pick ups and might go into cars easy to

Ford's had a few different IRS designs, the MN12/FN10 Thunderbird/Lincoln Mark VIII you're referring to here, the '03-04 Mustang Cobra, the Lincoln LS, etc.

As for the MN12 setup, it's pretty wide, and quite bulky, and you need to pay attention to what parts you're getting (most V6 'Birds had a 7.5in diff and stinky drum brakes, the Thunderbird SCs had iron 8.8s and discs, the Lincolns had aluminum 8.8s with lousy 3.07 open diffs but had aluminum lower control arms and air bags where the 'Birds had cast-iron lower control arms...) and it's a Ford so almost everything was NLA'ed by Ford at least a decade ago, it always amazes me that you can get parts for 20-year-old BMWs with no trouble but any post-1980 Ford is always a disaster.

Not entirely HAMB-able but if you insist...



'64 Country Sedan frame with modified MN12 Thunderbird SC subframe (the front legs had to be narrowed and lowered to mate up properly to the Galaxie frame, easy once I made the jig to do it, unlike some of the truck conversions I'm retaining the original rubber mounts), Mark VIII aluminum lower control arms, '02 Explorer 8.8 rear cover, fabricated rear diff mount with E39 BMW bushings, everything tacked for trial-fitting...



Subframe is bulky enough that there's bugger-all room for the stock gas tank here, I'm planning to do a fabricated aluminum tank under the driveshaft in front of the subframe similar to the MN12 'Bird and a lot of other late-model products.



The 285/40-18 tires look pretty small once the car's back on its wheels, it's not all that low, 6 3/4in from ground to frame as it's set up here. Note that the IRS is just about exactly 3in wider hub-to-hub than the stock Galaxie axle, necessitating some extra offset in the rear wheels.

[mgtstumpy]

An old HAMB thread http://www.jalopyjournal.com/forum/s...d.php?t=381637

[LIFESTYLZ]

The Ozzie GM Holdens have a good LSD IRS set up as well.
Cheap enough as well.
Just picked one up for $200

[mustangsix]

Originally Posted by jrblack30

Here is one but I dont think it uses any 9" gear

That's not a Jag centersection. Looks like some kind of quickchange.

Ditto on not really needing the trailing arms. They aren't there to locate the control arms like on a Vette. They are there to help stabilize the assembly from rotating.

The cage is only held at four points on some rubber mounts and the top and is very wobbly without the arms. Just rebuilt the IRS on my OT Jag XJS and it only took about 30 minutes to undo everything and drop the entire rear from the car.

[jrblack30]

Guys,

The image I placed up there is an all Aluminum Halibrand Independent Quick Change that I have been working on for a customer.

[JEM]

Originally Posted by LIFESTYLZ

The Ozzie GM Holdens have a good LSD IRS set up as well.
Cheap enough as well.
Just picked one up for $200

I think I've been to the Holden museum where that pic was taken...

That semi-trailing-arm rear suspension originated in the early '90s Opel Omega/Vauxhall Carlton, Holden borrowed it and beefed it up, later ones got a toe-control link that originated on the Lotus Omega/Carlton. Holden thought highly enough of that setup's durability to use it on 3/4-ton utes, as I recall.

In the US that rear suspension's shown up on the '04-06 GTO and the subsequent and much-missed G8, GM's last attempts at resurrecting the Pontiac brand from the horrible plastic-trash reputation it'd descended into from the '80s forward.

Given what the marketplace thought of the Pontiac name by 2004 GM would have been better off just selling them as Holdens.

[davidfe]

JEM,

Love the long roof. Had another make and model for years. Loved
the ride and what I could carry.

Looks really good. Will be interested seeing your experience in how it rides.

David

Originally Posted by JEM

Ford's had a few different IRS designs, the MN12/FN10 Thunderbird/Lincoln Mark VIII you're referring to here, the '03-04 Mustang Cobra, the Lincoln LS, etc.

As for the MN12 setup, it's pretty wide, and quite bulky, and you need to pay attention to what parts you're getting (most V6 'Birds had a 7.5in diff and stinky drum brakes, the Thunderbird SCs had iron 8.8s and discs, the Lincolns had aluminum 8.8s with lousy 3.07 open diffs but had aluminum lower control arms and air bags where the 'Birds had cast-iron lower control arms...) and it's a Ford so almost everything was NLA'ed by Ford at least a decade ago, it always amazes me that you can get parts for 20-year-old BMWs with no trouble but any post-1980 Ford is always a disaster.

Not entirely HAMB-able but if you insist...



'64 Country Sedan frame with modified MN12 Thunderbird SC subframe (the front legs had to be narrowed and lowered to mate up properly to the Galaxie frame, easy once I made the jig to do it, unlike some of the truck conversions I'm retaining the original rubber mounts), Mark VIII aluminum lower control arms, '02 Explorer 8.8 rear cover, fabricated rear diff mount with E39 BMW bushings, everything tacked for trial-fitting...



Subframe is bulky enough that there's bugger-all room for the stock gas tank here, I'm planning to do a fabricated aluminum tank under the driveshaft in front of the subframe similar to the MN12 'Bird and a lot of other late-model products.



The 285/40-18 tires look pretty small once the car's back on its wheels, it's not all that low, 6 3/4in from ground to frame as it's set up here. Note that the IRS is just about exactly 2in wider hub-to-hub than the stock Galaxie axle, necessitating some extra offset in the rear wheels.

[davidfe]

I have been following the recent thread about the JAG
IRS. Here are a couple of links I have found and am still
reading.

IRS in a Classic Mustang

http://home.bresnan.net/~dazed/JaguarIRS1


IRS Forum which covers all makes and models.



http://irsforum.boardhost.com/viewtopic.php?id=242


Fad in the Making


http://www.jalopyjournal.com/forum/s...d.php?t=530352

yel with body on4.JPG is the link to the posting of his JAG IRS rear end.

WOW lots to see and learn.

Hope this helps.

David

[ThunderRocket]

Wow, that Mustang/XJ info is priceless!