Steering not returning to centre after a turn.

[Plums]

As the title suggests, I'm having some problems with my steering set-up.

My main concern is that the wheels don't return to centre after a turn. Secondary to this, the car seems "twitchy" while driving on normal roads. It's not bad at all but it's just a "feeling" I get....

With my limited alignment experience here is what I have done:

Toe: Toe'd in front by 1/8 inch. Rear seemed very close to zero so I left it alone. (This of course is just done to the best of my ability on the hoist at home, I don't actually have any speacialist aligning gear!)

Camber: Looks like about 2 - 2.5 degrees on the front and 1 - 1.5 on the rear. I haven't touched it at all but would like to get the rear close to zero. (I know how to adjust these I just haven't done it yet)

Castor: This is where I'm lost. I can see shims in the top arms (quite a few, in front of the balljoint) which appear to give some negative castor. I thought I actually wanted a few degrees of negative castor??

I understand that castor is a major factor in the stability (tracking) of the car AND affects the self returning steering factor as well.

Can anyone offer some advice or previous experience here???

[mickmate]

You're on it, more caster will make the steering return to straight and in turn requires more effort to steer. Try around 3 degrees of caster. You can get close with a cheapie protractor level but you really need to get it to an alignment machine soon.

[PatBuckley]

Great advice on the castor but also make sure that the front end has been lubricated/greased.

[Aussie Mike]

Remeber your upper and lower arms are right and left handed. If you get them round the wrong way you will end up witn no castor or even negative castor.

When I first got mine together I had the top arms round the wrong way and I had about 8 degrees positive castor. Great for a drag car but hard on the arms when you want to turn corners.

Ideally you want about 4 degrees of positive castor. When you look at the upright from the side the top pivot should be behind the bottom pivot so the upright leans back.

Cheers

[Plums]

Here are a couple of pics. (The rotors and calipers should look very familiar to someone on here!)

In this first pic it looks to me like the "upright" is leaning backwards. Have I got this right? Does this look to be somewhere in the ballpark???



The second picture is of the adjusting shims in front of the balljoint.

[bobcowan]

You have way too much toe in.

Without a caster/camber gauge, there's no way to actually set them accuratly. You'll mess around with it for a week and never get it right. Bite the bullet, and buy a gauge. They're cheap enough that it's not a big deal.

I use this one from Pole Position: http://www.racerpartswholesale.com/polpos.htm

Set camber at about 0.5*, Caster at 4-5*, and toe at 1/32" total. Then you can make fine adjustments based on performance and tread temps.

[alffie]

Why dont you take it down to the tyre shop and get a wheel alignment?

[Rebel1]

That looks like way too many shims. Total of three is normal.

Series 1 upper arms are handed.
Series 11 upper arms are identical front and back.

Standard Jaguar castor is 2.25 degrees +/- 1/4 degree but that is for a much heavier car. 4 degrees is good starting point for a much lighter cobra.

Each standard shim (1.6mm) will alter castor by 1/4 degree.

Are you sure you have series 11 lower arms. Using series 1 lower arms will reduce castor by 2 degrees.

Cheers