Castor correction kit

[George Wilder]

Jim
See my other reply re tyres in technical.

I have run my roadster with 3/4 inch roll bar, 480 lbs front springs and GT rear springs along with lever arm shock absorbers fitted (not recons) all round with 165 radials with 28 front 24 rear for some years now. As you have found this works really well with a good handling car no body roll etc.

[Peter Cresswell]

Jim Haines wrote:
> I have read your response to my post, and feel I should make you aware that
> fitting instructions for the kit we used, and which we followed at the time
> of installation, make no mention of any need for any gauges etc., only
> stating that the tracking/toe in should be checked after completing the
> installation.
> I still have these instructions if anybody would like to see them.
> Having driven the car quite a few miles since this was done - a few years
> ago now - I do not believe there is anything amiss from not using the
> gauges you have referred to
> Yes - it could be said that the price was not cheap for what is essentially
> only 2 cast aluminium
> tapered wedges but I guess I got the benefit of their knowledge and,
> hopefully, simplified method of installation.

Hi Jim
I take your point but they probably also tell you to follow the guidance in the workshop manual for alignment.
When you tip the front of the cross-member down to take off the 3 deg of castor, the mast of the steering rack moves up and out of alignment with the steering column. In fact it moves up by over an inch at the universal joint. In order to correct this, the rack has to shimmed under the lower bolt, and the B&G kit includes extra shims to do this. The gauges allow you to make sure that the centre line of the pinion mast and the centre line of the steering column meet in the centre of the universal joint, so the joint is completely unloaded. If the wedges are simply pushed into place you will not have seen the misalignment which is obvious if the universal joint is disconnected. See Chapter 11, Section 23 of the Haynes Manual or Section J 'Steering column alignment' of the BMC manual.
If the two parts of the column are not aligned the unversal joint will load the pinion upper bearing causing rapid wear and steering stiffness. When I did mine I had to guess the alignment, and the steering was not as light as I expected. I based this on driving Gerry Brown's FIA race/rally car, which is decastored, has a lot of negative camber, a high ratio steering rack, and a 13" steering wheel. The steering was almost feather light!

This also applies to the MGA and MGB V8 but not the MGC as the crossmember is welded into the body so the rack alignment should always be correct providing you put back any shims used by the factory.

[Peter Cresswell]

George Wilder wrote:
> Jim
> See my other reply re tyres in technical.
>
> I have run my roadster with 3/4 inch roll bar, 480 lbs front springs and
> GT rear springs along with lever arm shock absorbers fitted (not recons)
> all round with 165 radials with 28 front 24 rear for some years now. As you
> have found this works really well with a good handling car no body roll
> etc.

George and Jim,
I agree with your suggestions on tyre pressures, and I too have found 27/28psi front and 24 rear to be a nice experience. The higher front pressures help stop the understeer and sharpen up the cars ability to change direction.