Rear Toe

[redmt]

Has anybody had rear toe in issues with the Jag IRS? I have 1/2" toe and before I make my intended modifications I figured I'd throw this out for any input from anybody else. BTW, it's all stock XKE with all bronze bushings.

[RICK LAKE]

redmt Red if this car is drivin on the street, IMO too much toe.
Here's ERA's specs for their street setup
front camber "0" + /- 1/4"
front caster "4.5" +/- .5"
front toe + 1/16 +/- 1/16
rear camber -3/4" +/- 1/4"
rear toe "0" +/- 1/16.
thrust angle "0"
this is with your weight in drivers seat and a manual steering rack this is with my weight in the car and running a 51/49 front to back weight percentage with 1/2 tank of gas.

I run track and auto cross with a Appleton rack P/s
front camber 1/2"+ both sides
front caster 3.5"+ left side 3.75"+ right side
toe 1/8"+ to 3/16"+
rear camber 1/2+ both sides
rear toe -1/8
thrust is "0"

You can run these numbers on the street also.
Every car likes different setups for driving. If you are serious, buy a heat temp probe for the tires. Go out and drive the car on a hot day and warm the tires up. and do a quick temp reading of all tires from inside to outside. You want to see the same number across the width of the tire. This test shows you are getting tire patch to the road and the best handling. It's time consuming but IMO worth the extra work to get the cobra to handle.

You did leave out some things like track or auto cross needs about a 30% high spring rate in the front, different toe setup, ackerman turning angles being setup. Another easy thing is to video the car going around turns and look at the car angle of attack. I like the car nice and flat around hard turns. I also went to double adjustable shocks for dampening and rebound.
Does this car have both front and rear sway bars?
I have solid poly bushings in my Jag rearend. keep them greased and have been running the same set for 15 years of abuse. No play yet. This also helps with straight line abuse. My car squats about 1" and leaves in a straight line. Both rear tires have the same tire pressure. Again reasons for setup being important. Good luck Rick L. Ps depending on your driving style some of this works and some doesn't. If you like drifting a car in turns these specs may not work with out alot of torque. I like going point to point and do a little drifting of the car in turns. This over heats the tires.

[DanEC]

Do you really mean 1/2 inch or possibly 1/2 degree? I can tell you that ERA specs are 0 to 1/16 inch toe in or 0 to 1/4 degree toe in for the rear.

[redmt]

Rick, Thanks for the reply but I'm in the initial setup stages of a new build.
I mean 1/2 " not 1/2* they are toed a full 1/2 inch.

[RICK LAKE]

redmt Red Alignment is last to do before driving on the street.
Need to get a basic ride height in the 4 corners of the frame.
After this need to get the car scaled. I think on just about all cars you need to move the battery to the trunk and place it on the shef over the rear right tire. This makes about a 50 pound different from being in the front on the right side and helps balance. Some guys use to small batterys and have them behind the passenger's seat. Good place, keep the weight as low as possible in the car, but I like the 50# for traction to help the r/r wheel.
Get the car running, get some weight in it with a full tank of gas, motor,trans, rearend and everything else. Let the car sit on the ground for a couple of days to break in the springs and get a good starting point. If you have a quiet road, I went and did figure "8" to load the suspension. About 10 turns each way with a total of 30. Make sure WHEELS DON'T RUB BODY.
Last note go back through the whole car and recheck nuts and bolts for correct torque.
You might want to look for a watt's linkage for the rearend of your car also. If the car is setup and skip the burnouts for the friends it's not needed, BUT if you show off that rearend will be shaking in the frame. I have seen the rearend move upto 2" in the rear openings. Contemp used to sell a kit that reduce this power by about 95%. The only thing that used to break was the pivot shoulder bolt in the top the the rear housing. Contemps system was setup to have no binding of the rearend under hard stopping of accelleration. and it worked. I gave my kit to another Contemp guy. It wouldn't work on and ERA frame with square tubing. Good luck Rick Ps Take a look at a caliper or ruler and look at what a 1/2" is. I think you will see that this is too much ans will wear the crap out of the rear tires. 1/16" to 1/8" is all you need. To get the rearend in toe spec you haave to add shims at the lower mounting points where the "A" arms mount to the center section. These bolts are safety wired and will need to be redone after alignment. I can talk you through this on the phone. too much to type Rick l.

[patrickt]

Rick, I meant to ask this of you on the last rear end thread, so this is really kind of on point here.... I know you recommend re-packing the front wheel bearings periodically, which is a cinch... but what do you do for the rear wheel bearings, on the Jag and ERA rear?

[redmt]

Thanks Rick. I had the fix pretty well figured out in my head but was looking for somebody that has done it to verify I was on the right track. The toe adjustment needs to be done during initial setup. It would be a royal PITA to try and strip all the rear suspension down after the car's all built. As you probably remember, the spreader tubes on the A arm brackets to the rear end don't permit room to loosen and tighten the bolts without removing them first. Besides that, a bare frame is much easier to slot the forward cross member to allow movement of the fulcrum shafts.
As an answer to Patrick's question, I heavily packed the bearings during assembly with a high heat , high pressure grease. I also removed the vent plugs in the housing and tapped them out to pipe thread so that an occasional squirt into the housing of fresh grease can be applied should they need it. Of course if a wheel/axle seal should start to leak a tear down would be in order.

[RICK LAKE]

Patrickt Pat I have contemp rear housing on my jag setup. There is a grease fitting to lube these bearing for the outter assembly. I would think the same could be done for the OEM housings. I run Lucas high temp red grease. I apply it the same as doing the u joints about 2 -3 shots or if the pressure builds on the grease gun. it's a feel. I don't see why you could drill and tap a grease fitting into each hub. I would have to look in the shed at the stock outter housings to see if this is possible. The Contemp housing have no vent hole I could see. Rick L.

[strictlypersonl]

rdmt,

If you really have 0.5" toe-in in the back, and you're using a tie-bar, one or both of your lower control arms is very likely bent. That assumes that all of your bushings are really concentric.

[redmt]

Originally Posted by strictlypersonl

rdmt,

If you really have 0.5" toe-in in the back, and you're using a tie-bar, one or both of your lower control arms is very likely bent. That assumes that all of your bushings are really concentric.

Yes , I really have 1/2" toe on the rear. Yes there is a tie bar and yes the bushings are new and concentric to .0005 and no the control arms are not bent.

[strictlypersonl]

Originally Posted by redmt

Yes , I really have 1/2" toe on the rear. Yes there is a tie bar and yes the bushings are new and concentric to .0005 and no the control arms are not bent.

How do you know? Have you measured? On an undamaged lower control arm, the inner and outer pivot axes should be parallel.

If you are correct, the lower pivot axes must not be parallel due to invalid spacing from the centerline of the car. You're using a tie-bar at the back, correct?

The only other thing I can think of is a twisted hub carrier. Not likely on an aluminum casting. In 1000 cars, I've never seen one twisted but unfractured.

[redmt]

Originally Posted by strictlypersonl

How do you know? Have you measured? On an undamaged lower control arm, the inner and outer pivot axes should be parallel.

If you are correct, the lower pivot axes must not be parallel due to invalid spacing from the centerline of the car. You're using a tie-bar at the back, correct?

The only other thing I can think of is a twisted hub carrier. Not likely on an aluminum casting. In 1000 cars, I've never seen one twisted but unfractured.

OK,,,, not to be a smart (or dumb) ass , but this isn't my first rodeo. Everything and I mean EVERYTHING has been measured within an inch of it's life. The arms have been switched side to side, The hubs are identical side to side. The ONLY thing I can fathom is that the brackets that bolt to the carrier somehow are align bored a bit off. The ONLY thing I can find is they the fulcrum shafts didn't quite line up with the holes drilled in the cross member of the frame but then the height of the carrier was off about 1/16 too. I contributed this to the welding jig it was built in. The carrier was out of square to the frame by around 1/8" so I slotted the holes a bit to square it to the thrustline of the frame. My next move is going to be to shim the front of the brackets at the carrier to spread the toe out.

[strictlypersonl]

Typically, the inner brackets are shimmed out from the differential to give the proper toe value. On the stock Jaguar setup with subframe, the inner pivot axis is fixed by the holes in the subframe itself, and the space between the brackets and the differential casing is filled with appropriate shims. The geometry is determined by the subframe, not the differential casting.

[redmt]

Originally Posted by strictlypersonl

Typically, the inner brackets are shimmed out from the differential to give the proper toe value. On the stock Jaguar setup with subframe, the inner pivot axis is fixed by the holes in the subframe itself, and the space between the brackets and the differential casing is filled with appropriate shims. The geometry is determined by the subframe, not the differential casting.

That is sort of what I figured,,,, I've never seen one or noticed one with shims. I suppose it is possible that they were never adjusted on other cars and the builder took it for granted that it was correct. Me,,,,, I check and double check everything as I go and then check and double check each assy. and what it's relationship is on everything else. I've worked on a few other cars and the suspension geometry was a joke. The hack that set up the suspension on Ron Wideners coupe didn't even have the A-arms in the same plane yet nobody even noticed.
Thanks for the input. It verify's what I finally figured out. On the good side, I now know that all the components are true and square.

[joyridin']

Just out of curiosity, did you get the bronze bushings from Classic Jaguar (Team CJ)?

[redmt]

Originally Posted by joyridin'

Just out of curiosity, did you get the bronze bushings from Classic Jaguar (Team CJ)?

Without digging out the receipt, I'm %99 sure that's where they came from.

[1985 CCX]

I am thinking bent.
CCX has a weak point and it either needs ERA type bracing or a watts linkage.
Mine ran straight, also had s few extras. Never did the watts. Was planned next but I went to another car.

[redmt]

Originally Posted by 1985 CCX

I am thinking bent.
CCX has a weak point and it either needs ERA type bracing or a watts linkage.
Kind ran straight.

I wish something was bent. It would have been easier to replace or straighten but that's not the case. Watts linkage has nothing to do with initial setup. It can prevent issues in the future but not now. I'm not familiar with the ERA setup, but that also doesn't have a bearing here. (no pun intended)
I don't know what "kind ran straight" means?

[RICK LAKE]

redmt REd where the rear arms shorten and rewelded? I have seen some real hack shops with welding. If manual is doing this he starts and goes all the way around in 1 burn instead of short welds every 90 degress and checking for center. This would be my guess. The other thing was a smaller diameter tube installed in the lower arm before welding was done. With better than 15 years of racing have seen lower control arms seperate at the welds. From the quick look, not enough penatration or ampage. I think CWI used to sell lower arms made of aluminum. They where machined from 1 piece and bolted right in. IMO I don't think anything from Jag was setup correctly in the rear ends. This was for camber or toe. My rearend setup has a subframe that the jag rears is mounted into. I had to modify the outter mounts where the pivots for the arms are. They where over 1/2" out. I got everything in spec and welding heavy flat washers as locators if I every had to pull the rearend at a track and swap or repair. I have on l/s front pivot 7/16" thickness of shims and 3/8" in rear l/s side. R/s have 1/4" front and 3/8" rear. The mount plates are 2 degrees on the diff housing. The locating trailing arms have a mount like the old 63 dodge darts with 2 large bushing and they adjust to locate wheel in wheel opening. Was thinking of going to a solid mount but The rear carriers needs a little freedom to move and not start breaking parts under hard loads or abuse. The housing that holds the carrier also has to large pivot bushings at the top and centered. I like this engineering over mounting the Jag rearend directly to the frame of the car with the 4 upper bolts.
If the arms are not straight and true to your liking, have them redoneand find a guy who knows how to weld. Don't forget to add gussets from the tube to the end supports on both sides. I know you know this. Good luck Rick L.
Ps if you goto the Watt's linkage and use the Contemp setup, get a thicker pivot shoulder bolt and carry a spare. lowes sells them. They snap under hard load or alittle abuse. The thread end is only 5/16" need to goto 7/16 or 1/2" with drilling and retapping the hole.
Sorry last note I have listened to alot of guys about running needle bearing or bushings in the rear pivot mounts for the arms. I did modify the bushing to allow grease to get to the shafts. They are the poly white ones. 15 years of abuse and still have no wear. I know the bearings should hold up as long with proper maintainance too. With little grease grooved in the bushings I do like them better. I have checked and found no deflection yet. Again under hard track loads they may be moving. For the serious guys a couple have gone to aluminum bushing inserts. Bootom line, Red through out the book and change or modify what you need to. Look at Nascar and bending rear tubes on a solid rear diff for better handling? Ride them COWBOY.