I did some work on the steering of my 1968 S Type last week and now I need to have my front wheels re aligned. In the blue book it states that the alignment should be parallel to 1/8 of an inch or 3.2mm total toe-in measured at the rim. Does anyone know what this relates to in degrees as I think all modern alignment machines work on degrees of toe-in.

 

I think the machines should be able to do either degrees or a distance measurement. I use about 1/8 to 1/16" toe in, don't go to parallel. Also put as much castor in as you can, the old reccomendations in the book are not good for stability.

 

Yes ~ standard was basically zero caster or camber & 3.2 mm toe in.

Most modern 4 wheel alignment machines can't handle our cars because of the rear wheel arch not allowing fitment of their rear units. I agree with max caster but in reality not much can be done ~ I left mine standard. Modern cars like Benz & BMW run +- 10 degrees of caster for high speed stability & centering & some negative camber.

Remember with Varamatic that steering box is centered and toe adjusted with the side tie-rods. Opposite to Burman where the side tie-rods are fixed & toe adjusted with the centre rod.

Weight the car correctly & let your alignment shop sort their machine with the 3.2mm toe in. Make them bounce the car a few times on the plates to ensure setting remains constant.

Good luck!

 

On mine glyn the variomatic is centered but I have a fixed arm on the right side but there are adjustable ball joints on the left side. In the center there is and an adjustable tube. To be able to drive it to the wheel alignment garage I have had to try and center the wheels. The right side wheel is fixed straight with the steering box and then by releasing the locking clamps the adjustable center tube is rotated which moves the left side wheel in or out into alignment. To get everything pointing straight I ran two straight edges of wood down the side walls of the tyres and measured the difference in front and behind the straight edges. I then adjusted the centre tube until I had a slight toe-in. Very crude but good enough to drive it the five miles to the garage to have it set up correctly.

 

(1/8)/15 = 1/120 radians ~ half a degree

 

...and pieces of wood and a tape measure, repeated with the wood rotated (and the wheels), can often be more accurate than the very expensive laser device.

 

Something has got messed up on your car at some time. You should have adjustable length tie rods on both left & right side to set toe. Varamatic steering box centered & idler aligned to it at straight ahead. Dial in toe at 1.6mm per side with left & right tie rods. Remember you have variable ratio to a specific curve both left & right of centre.


On original Burmans like mine you had fixed length LH & RH tie-rods due to reverse threading on one joint. You just screwed the tube off of one joint & onto the other. No length change. This was done so you could replace worn joints individually. With Burmans only the centre rod changed in length with rotation of the tube to set toe. Some final build Burmans had fixed length LH & RH tie rods that you discarded if one joint failed. You could not unscrew the ball joints & replace.

 

My November 65 build date car had that.

 

That seems early. It might have had a change already. But we are talking Jaguar here that used what they could get supply of.

 

I agree with Jagboi64, Do not worry about following stock settings but instead go for what makes the car perform better and track better. For me I want to push the performance more and am ok with having the inner 1-2" of the tire wear a little more as it does not limit the life of the tire and for me I find the following to work well:
Front
toe: 1/16” to 3/32” in
Camber: 0 to 1 negative with 1 being negative preferred
Caster: 4 to 6 positive. The actual number between 4 and 6 is not important, only that both sides are the same.

Rear
Toe: 1/16” in
Camber: 0 to 1 negative with 1 being preferred.

Before you go to a good alignment shop buy a good amount of the various stock shims as they are cheap and these cars are old school using shims for a lot of the adjustments so they can play around with adding/removing to get it to a nice setting. Since your car is more stock I would recommend something like the above but start with the camber about .25 to .5 negative and see how you like it; I am running 1 or a little over 1 degree negative and am getting full life of my tires where the outer tire is at the wear mark and the inner 1-2" are balding & I rotate the tires periodically and am getting full tire mileage. The best is have them set it, drive it for a week and then you can always go back for a minor tweak of the camber, the other settings are not likely need to be adjusted much if at all.

 

I agree as I said to Jagboi as long as you don't mess with Varamatic toe setting procedure. That causes many issues with variable steering angles like pulling with the camber of the road and wheels at different positions on the variable curve from centre. There are ways to fix pulling with the camber of the road but then you are fixing the symptom you have caused.

Are you able to get to 4 to 6 deg positive castor without your front suspension mods? I don't think so? I would like to dial in max caster achievable & some negative camber. I've got plenty of shims from my 2 donor cars. I would love to get to my Merc's 9.6 to 10.6 deg caster but realise that's not possible nor is their variable camber with steering angle. Each shim achieves 0.25 deg change IIRC. So you can only move from vertical by approx 50% of the shims (10 shims total). That is only 1.25 deg positive caster adjustment max. Not going to make much difference.

Jaguar settings on these cars were done to achieve lightest manual steering & they did not even consider anti dive until the XJ6.

 

Glyn has identified the whole basis of the stock settings: to make the manual steering as light (or less heavy) as possible. With power, there's no reason to stick with them. The trail in the wishbones makes camber and caster adjustments interact in what at first may seem an odd sort of way. If you look at how the upright will move as you add or remove spacers, it becomes clear. Unless you know a good shop, it's the sort of thing I'd do as well as I could at home and have the alignment shop do a check and final adjustment.

 

Another point that Glyn made was increase of caster with steering angle. This is usually arranged by having large caster: as you steer, the outside wheel tilts in (think of a motorcycle) giving the tyre a better contact patch. With the king pin angle of the Mk2 and little caster, the outside wheel tilts the wrong direction as you (try to) steer. You may have experienced that unpleasant feeling of turning a Mk2 steering wheel to tighten your line in a corner and finding it has less and less effect. As Bob Jayne said, the throttle is for steering; the steering wheel serves mainly to slow you down.

 

That is why I recommended to buy a bunch of those cheap shims, as once a decent alignment shop sees and understands the old school approach of the Jags with shims all they needs is plenty of spare shims and the computer will make it easy to dial the suspension in for better handling. This is one area in my opinion you should tweak with the help of an alignment shop for performance not to original spec.

 

Another good reason for having spare shims is in case the worshop loses one - which they may well do. For the adjustment that primarily controls caster (the one that moves the top ball joint realtive to the wishbone), it's important to keep the total numbers of thick and thin shims in place. Move them from one side of the joint to the other, but don't leave any out. Otherwise, the pivots of the wishbone don't align properly with the bushes and destroy the bushes. Don't ask me how I know.

 

Especially if you are outside of the UK, where shims are likely non-existent unless you drop your car off and give them ample spares to use as needed Most cars do not use shims anymore and those things are cheap like the cost of a hamburger

 

You can as long as you ignore the manual. Basically you have to treat it like a 1974 Buick. Move all the shims to the front of the ball joint to lean it back as far as you can. That will give you perhaps 1-2 degrees - not enough I found, the car still wanted to wander. So then I adopted the Buick method and added shims between the upper control arm and the subframe, but only at the front. That had the affect of rotating the upper control arm around a vertical line and also leaning the ball joint backwards to give more castor.

It took my car from not being able to stay in a 12' wide lane and darting all over the place to a driving line a modern car, where it drove in a straight line and stayed where I pointed it.

 

The tools are not that expensive, it might be worth it to buy the tools and do the alignment yourself. Castor/camber isn't hard to do.

 

Now checked with Service & Parts Manual:

Are you able to get to 4 to 6 deg positive castor without front suspension modifications? I would like to dial in max caster achievable & some negative camber. I've got plenty of shims from my 2 donor cars. I would love to get to my Merc's 9.6 to 10.6 deg caster but realise that's not possible nor is their variable camber with steering angle.

Each shim achieves 0.25 deg change (0.064") (one quarter of a degree). There are 2 packing pieces & 10 shims total (no space for more). Shims are all the same thickness. So you can only move from vertical by approx 50% of the shims plus one packing piece. That is only approx 1.25 deg positive or negative caster adjustment maximum by shim movement plus 1 packing piece.

Is it possible dial in more than approx 1.25 degrees (shims) plus the small packing (thickness not quoted) piece of positive caster without suspension modifications to achieve meaningful caster change?


CASTER ADJUSTMENT

 

Sorry ~ we posted over one another while I was reading manuals. Your picture shows Camber shimming which I understand. Can you show me a pic of your main Caster alignment.

What does your total alignment look like on an alignment machine ~ Hunter or whatever. Any strange behavior from lock to lock or pulling with the camber of the road or tramlining?

I agree with you that 2 deg caster is hopeless if you are going to go down this route. My car is pretty stable but everything is new including shocks. But it's not a patch on my Merc & neither would I expect it to be. I'm also keen to fit the rear anti roll bar/swaybar like the E Type. All the mounting points are there standard on an S Type. A company in the UK makes the wider bar. It's bolt on bolt off. Zero mods required.