Jag rear end width question...

[Fullchat289]

Hi, Bob/others:

I have what has been identified as an S-type rear end unit. The halfshaft measures approx 16.25" from the inner/outer U-joint centers. Is this width OK for modification for use in an FIA using the Trigo wheels? Just wanted to make sure as I understand that the E-type, S-type, XJ rears had different widths.

Thanks!

[strictlypersonl]

Al ,

The S-type will work. It's still too long to use unmodified, but we'll shorten it as part of the "Subframe Package".

[Jim Holden]

Full:

The XJS rear should be a posi unit. Check to make sure. Also, check to see if the ratio tag is still on the case/rear cover bolt. The rear ratio will help you decide what trans to go with.

Jim

[Fullchat289]

Thanks, guys.

Jim:

No, S-type salooooooon, not XJS. Unfortunately (maybe) it's a non-powerlocking diff. I purchased it because it was complete and the right price thinking that the powerlocking diffs were easy enough to come buy if I ever decide to get all competition-like. I suppose it would be nice to make two stripes on the pavement rather than one. I'll think about that one.

As far as the ratio, I believe it's a 3.31. I haven't looked at the tag for a bit, but this comes to mind. Looking at ERA's charts, my heart says Toploader, but my brain says Tremec. I presently have a 289 block that I would like to build-up with a stout cam and AFR's, starting out with a Holley, then moving on to Webers or a stack injection system as a winter project. When the time comes for me to actually make these hard decisions, I'll be sure to elicite the advice of the fine folks here on CC as well as the David Kee's and Mike Forte's of the world.

Thanks!

[Lynmac]

Hello

For what its worth we have a Jag rear end and a 3.31. Hubby has put a Mustang T5 in and it marries up quite nicely.

Fullchat289 wrote:
"As far as the ratio, I believe it's a 3.31. I haven't looked at the tag for a bit, but this comes to mind. Looking at ERA's charts, my heart says Toploader, but my brain says Tremec"


Regards
Lyn & Peter McArthur
Australia

[Jim Holden]

Al:

You definitely do not want an "open" rear. What year (if you know) is the dif.? Is it the same Salisbury unit that is in the earlier XJ sedans? (You need to be precise with Bob at ERA to make sure it will fit their cage.) Did the car have inboard or outboard brakes? I have a 3.31 rear with a Tremec TKO and 5th is very "long." Were I to do it again (and I may) I would consider a Richmond Gear 5 speed with 5th being a 1:1.

Jim

[strictlypersonl]

The S-type casting will fit fine. I'm pretty sure that a new LSD can be retrofitted with the 3.31 ratio, although it's been many years since we've used something besides the XJ dif.

[Fullchat289]

Jim:

Yes, it has the inboard brakes, and thanks for the thought on the Richmond Gear.

Strictlypersonal:

Do you guys normally have people purchasing units off of you rather than sourcing a unit and opting for your control arm and halfshaft modifications? I know the Jag rear can be a challenge to rebuild properly with all the shims, etc. Seems like the parts are easy enough to source, however. It's all a bit fiddly, but for an Engineer, it's art. Also, I wasn't aware that there were that many design changes to the center casting over the years and accross the different models. It's kinda like a guy put it to me this past weekend, Jag-U-ar is a small company with a big name. Anyone knowing the company prior to the Ford purchase could probably attest to that.

Cheers, mates!

[mylesdw]

I am not 100% sure about this but I believe that all the Salisbury diffs used in all Jag IRS are the same (the parts are interchangeable) with one exception: at some point they changed the way the pinion is located from shims to a collapsable (sp?) spacer. I am not sure whether for this they changed the pinion shaft or the casing or both.

I have a 3.31 rear and top gear on the ZF five speed is 0.98:1. This set-up is still pretty tall and I would go for a 3.54 if I did it again.

[will butterwort]

need torque specks for jag. rearaxle shaft outer nut on end of axle that key goes thru. It is a reg. jag. w. 3:31 dana gears,, replacing bearings for second time left rear, i am not doing something right.Alabama. Thanks.

[mylesdw]

Will Butterwort: will look them up when I get home this evening unless someone else answers first...

[strictlypersonl]

Originally posted by Fullchat289
...
Do you guys normally have people purchasing units off of you rather than sourcing a unit and opting for your control arm and halfshaft modifications? I know the Jag rear can be a challenge to rebuild properly with all the shims, etc. Seems like the parts are easy enough to source, however. It's all a bit fiddly, but for an Engineer, it's art. Also, I wasn't aware that there were that many design changes to the center casting over the years and accross the different models. It's kinda like a guy put it to me this past weekend, Jag-U-ar is a small company with a big name. Anyone knowing the company prior to the Ford purchase could probably attest to that.

Cheers, mates!

The only control arms and axles that don't require modifications are from Series 1 and II XKEs. All others must be modified - but that operation is included in the price of our (manditory) subframe.

With a little patience and some measuring equipment (and the use of a press), there's no reason why you can't do the rebuild yourself. A good Jag service manual is a big help though.

[Jim Holden]

Folks:

A (not inexpensive) suggestion is to have parts such as calipers, hub carriers, etc. Airborn ceramic coated. It makes the parts much easier to keep clean. I've had it done on both my GT and FIA and as the years go by, I think it was money well spent.

Jim

[mylesdw]

Will Butterwort: I have the book in front of me now, can you confirm which specs you need? Is it the drive gear bearings in the diff that you replaced or the wheel bearings in the hub?

[will butterwort]

wheel bearings in the hub, drivers side rear, what do i torque it to when i replace them, that is the big nut that holds it all together that has cotter key thru. it Thanks.Alabama

[mylesdw]

"Locate the splines and feed the splined shaft into the hub. When the threaded end emerges sufficiently, fit the plain washer and the castellated nut and draw the shaft into position by tightening the nut to a torque of 140 lb feet. Fit the split pin"

[mylesdw]

There is also a whole lot of stuff about setting the hub bearing end float. Did you do that?

[will butterwort]

never heard about bearing end float, thanks for specks, will proceed when i get hub back from manuf. with new bearings. Alabama thanks.