Thanks, I will take a look at the sites. Here are some more of the markings. I think that it is a 3:31 gear ratio with a posi. I have taken it apart, and it has roller bearings, not ball..

Last edited by mcmopar (11/12/2013 3:04 pm)

With the gear ratio, the 74, and roller bearings, I would bet you could narrow this down to an XJ12 possibly from the 74/75 model year.
However, that stamp isn't always indicative of year.  When you orders parts or kits, any knowledgable shop will be able get to you what you need if you state you have a Series II Jag IRS.
Double check your gears.  I have a tag like that on my but the gears were changed at some point from 3.31:1 to 3:54:1 not a big deal but important to verify.  I'm also willing to bet you have a posi unit.  This is another indication of an XJ12.  Jag used PowerLok posi unit which has a smooth engage/disengage.  I haven't heard of anyone with problems with these.  These are meant for street driving rather than 1/4 mile monsters and should last quite some time.
On the surface, this seems like a solid unit.

Thats kind of interesting that XKE rear ends can be identifyed by width alone. All of the XKE's I have ever seen had spline drive wheels. Or spoke wheels with knock off's.  They have no flange to measure from. They have a dust cover incorperated in the splined drive hub. Most of the track widths I have seen were from the center of the stock wheel, Not the mounting flange or the dust cover.  Primarily because the spline drive hubs have a taper behind the splines to center the wheel not a flange. Pin drive hubs will have a flange with pins that locate the wheel similar to studs but will employ the knock off system as well. Therefore the flanged type hubs from what I have seen cannot be XKE.  That would rule them out as far as a width dimention. The only way possible to have an XKE width and flanged hubs would have to be a result of combining parts from different models. I have yet to see any  XKE's with lug nuts holding on it's wheels.  The XKE was Jaguar's flag ship.      The flange on the splined hub is there to make a loose fit seal to keep dust out. It's OD is much smaller than the XJ6's wheel mounting flange and if you were to see them side by side, the distance from the flange to the bearing  is different.    XKE's dust cover is much closer to the bearing journel than the XJ6's wheel mounting flange.  That would make using the dust cover flange on a XKE for a track width,  a mistake The chart Daze provided clearly says TRACK WIDTH. Not distance between dust covers!  Pointing out that the splined hub has a  flange was a mistake as well. Thats a dust cover,  It has little to do with wheel location unless you know how much off set to add per side. Since the majority of those hubs were made before the CNC's we have today and the dust cover is not a critically located part there may be loose tollorances on their location.   Adding to the error of using them for a reference point.  The chart didnt add that.        This is the difference between getting all your information from the internet and having  hands on experience.   I may have forgot about the dust cover but I was correct with my statment as to measuring flange to flange width on an XKE. 

Last edited by tyrellracing (11/18/2013 1:16 am)

mcmopar wrote:

Thanks 303radar, I will double check the gears while i have it apart. Is there a good spot for torque specs for this rearend? For the Ford 8.8 it has a additive for the posi lock unit, does the Jaguar have anything like this when filling the carrier?

Yes, there should be a specific fluid or additive for most any posi lock unit.  Not sure what it is off hand as I haven't re-filled mine since it has been rebuilt.  At least every posi unit I've had has used either an additive or a specific fluid.

Sure looks to me a knockoff/splined does have a flange. How can it not?

http://www.jalopyjournal.com/forum/showthread.php?t=744795&showall=1
Ralphy

Last edited by Ralphy (11/15/2013 2:34 am)

303Radar wrote:

mcmopar wrote:

Thanks 303radar, I will double check the gears while i have it apart. Is there a good spot for torque specs for this rearend? For the Ford 8.8 it has a additive for the posi lock unit, does the Jaguar have anything like this when filling the carrier?

Yes, there should be a specific fluid or additive for most any posi lock unit.  Not sure what it is off hand as I haven't re-filled mine since it has been rebuilt.  At least every posi unit I've had has used either an additive or a specific fluid.

Torque specs for which part(s)?  The only torque specs I've found came when I had my unit rebuilt - went from 19 spline to 30 spline.  And even then, they only apply to the ring gear.
Do a search on my posts, one of them posted a link to a shop manual which may have what you're looking for.

Maybe this is new info for you Jag guys.

"Here's a few stats if you like the idea of a Jag rearend: The XKE IRS from '61-70 was 53 1/4 inches wide and came with either 3.54 or 3.31 ratios. The V-12 '70-74 models increased in track to 56 inches with a 3.31 gear. All XJ6 units were 61 3/4 inches wide with 3.54 gears in the Series I ('69-73), 3.31 in the Series II ('73-79), and a super cruiser 2.88 in the Series III ('79-88). The S-Type ('60-69) was 56 inches wide and equipped with anything from a 3.31 to a 4.54 ratio, while the XJ40 introduced in '88 had a completely different non-interchangeable IRS. All XJ-S units were 61 3/4 inches wide with the early versions having a 3.31 ratio and the latter cars a 2.88."

"Jaguar fitted stamped I.D. tags on the lower bolts on the crown wheel cover stating the gear ratio, sometimes with the actual ratio and other times with the number of ring-and-pinion teeth. For instance, a 3.31 ratio will be stamped 43/13 (the ratio calculated by dividing the smaller number into the larger). One other point of interest with Jag rears is that up to 1995 they shared the common 5-on-4 3/4-inch bolt pattern with Chevy passenger cars, going metric after that year."

Read more: http://www.rodandcustommagazine.com/techarticles/0802rc_independent_rear_suspension/viewall.html#ixzz2ktLUQpfF

This must be what Day posted as track width.


http://irsforum.boardhost.com/viewtopic.php?id=163

Ralphy

Last edited by Ralphy (11/17/2013 2:26 am)

Yes Ralphy you are right. The wheels often get stuck with spline drive wheels. If you had the oppertunity to work on older cobras you would know that you always greased the splines and taper to make wheel removal possible. They were a miserable SOB to remove if they had been sitting for years and rusted up. That was agrivated even further if they had been installed with out grease. The rust would make wheel removal near impossible with out a special puller. The fact they got stuck often made them fall out of favor with anyone that got a flat and couldnt change it. . Pit stops could loose a race if one wheel got stuck bad.  I have seen the result of a spoked AC wheel that wouldnt come off on the road side.  The owner took his lead hammer and beat his wheel to scrap to remove it.  All early Europian sports cars used this design. None of them used a flange to back up the wheel. They relied on the taper alone to resist the outer nuts loading.  That includes the AC COBRA   Ralphy

tyrellracing wrote:

Yes Ralphy you are right. The wheels often get stuck with spline drive wheels. If you had the oppertunity to work on older cobras you would know that you always greased the splines and taper to make wheel removal possible. They were a miserable SOB to remove if they had been sitting for years and rusted up. That was agrivated even further if they had been installed with out grease. The rust would make wheel removal near impossible with out a special puller. The fact they got stuck often made them fall out of favor with anyone that got a flat and couldnt change it. . Pit stops could loose a race if one wheel got stuck bad.  I have seen the result of a spoked AC wheel that wouldnt come off on the road side.  The owner took his lead hammer and beat his wheel to scrap to remove it.  All early Europian sports cars used this design. None of them used a flange to back up the wheel. They relied on the taper alone to resist the outer nuts loading.  That includes the AC COBRA   Ralphy

That has got to rank high on the sucks a lot meter!

Thanks for all of your input. Now all I have to do is look for a good place to get rotors. Is there a place that has fair prices. Is it worth rebuilding the calaipers, or jest get new ones.

I made mine. I  finished a pair of 14"x 1.25" front rotors and aluminum hats a few months ago.Let me back up a little bit. I have made 4, 14" rotors. The first pair I made out of 4130 because I could get the steel free at work. They warped BAD. Then I used the autoclave at work to heat cycle them in an effort to stress relieve them.Over about 20 days of lunches and after hours heating and air cooling.  I cycled them about a dozen times hoping this would solve the warping issues. This made them hard as hell and after retruing them. The 1.25" thick rotors wound up being 1.125" and then they warped in the first 30minutes of hard use. Having learned why they use cast iron for car rotors, I purchased some 15" dia.x 5" malliable cast iron bar stock and made another pair. They  have performed flawlessly so far and are on my car now. To cool them I simply drilled .75" holes radially every 8 degrees making 45 holes then used a long .375" end mill to make holes square. I didnt square the holes on the steel rotors. It was just too tough to work with to justify the effort. These opperations were done on my super spacer for ease of locating the holes. This makes the fins taper but they seem to work fine. This has made me wonder what kind of steel street bike rotors are made from.  I am in the middle of making 6 piston calipers. I didnt have any blocks of aluminum big enough so I am machining them out of steel. Heavier than I wanted them to be but they will flex less. At least thats what I keep telling my self. If nothing else they will make good practice. The piston sizes are 2", 1.875" and 1.75" from trailing to leading. I wanted to keep all of the pistons on the pad with out overhang so I planned on using 6" long brake pads. I machined the calipers to accept 6" pads and thought nothing of it.  I have been using green Polymatrix pads in the 4 piston calipers I currently have on the car because I like the compound and they are readily available. I got 90% of the six piston calipers done includung  SS pistons before I started looking for pads. I didnt think it would be a problem. If I couldnt find the exact size I would get bigger ones and mill them to size. I havent had much luck finding the compound I like in anything bigger than 5.875" long. Live and learn. I have found lots of organic truck pads but they would have to be milled both in size and thickness.  If this sounds like more effort than most sane people would be willing to invest in 14" rotors, you are probably right. I just hate  paying for anything I can make my self. Besides the only used 14"x1.25" rotors I found on E-bay were $495 a pair. they go way up from there if you want new. The cast iron cost me $110 and I wont admit how much time I have in the four of them.

A lot of street bikes use stainless rotors as well as aircraft. High carbon steel is notorious for moving when going through heat cycles. If it were doable I'm sure an aftermarket company would have already done that.

Ralphy

Last edited by Ralphy (11/21/2013 2:46 am)

 no bragging here.    If anything it was an admission of using the wrong material on my first pair of rotors because it was free.  free can be too expensive when you dont know the alloy.  The steel wasnt marked. these were drop off's from the band saw. My lathe is strong enough that they cut like butter. It wasnt until I began drilling them radially that I knew I had chosen poorly. The rotors were done with the exception of cooling holes so I chose to try them any way. Thats when I looked into what project the drop offs came from.I initially thought they were mild steel.   I do know how much high carbon steel moves from machining it due to internal stress. Nothing new there.  Since I had never heat cycled the stuff I had no idea just how much it will continue moving no matter how much it is heat cycled.  My calipers are not a floating type so they will not accept much run out. .030 max before its felt through the pedal.  I made the rotors because I went from 16's to 19 inch wheels on the vehicle when I installed a Griggs racing front suspension.  I mounted the suspension higher on the frame to keep the ride height where I wanted it while maintaining correct geometry with the 19's.  The change from 16's to 19"s made the larger diameter disks a requirement if I was to expect sufficient stopping power. I tucked the jag rear higher as well. My rear rims and tires completely fill the rear wheel wells.  I  ripped the rear mounts off the frame twice when the set up began to devolop wheel hop so I removed the T5 suspension. The wheels wouldnt have worked with it any way. I do have all of this documented with photos including readouts from a hunter laser alignment computer. I have been sitting on this as proof of my claims from previous arguments. But who cares about physical proof when we cam discuss all of the maybe's involved  Yes ralphy I was told  similar information on the stainless rotors from another source earlier today.  My bad I see I high jacked your posting but I felt I should at least fill in the blanks. On my Jag rear I used fox body mustang rotors with their centers removed so aluminum hats could be used. I put spacers in my calipers to accept the new width. I use mico lock on my front brakes for a parking brake. It also allows me to do power brake burnouts with out applying any rear brakes at all.  I dont care for solid rotors burried so deep under a car that their cooling is poor. My car has scoops with ducting for the rear brakes and it is barely sufficient to keep vented rotors cool. 

Last edited by tyrellracing (11/22/2013 2:34 am)