Castor setting

[dlgis]

Hi, we’re about to start on suspension settings soon and according to the manual for the 3.8 Castor should be set at 2degs positive (+/- half deg). But what I wanted to check is where the 2 degs is measured from. Thanks

[abowie]

Basically you measure the camber with the wheel turned in and turned out by the same amount (I use 22.5 degrees) and subtract one from the other, giving your castor angle. Have a look at Youtube and this will make more sense.

What castor does is facilitates self straightening of the wheel when you have turned. So if you turn into a corner the castor tends to make the car steer straight again.

The one problem with this is that the more castor, and therefore straightening force, the heavier the steering. With a modern car with power steering this is not a problem. They are set with castor angles of around 5 degrees.

But with your E type, with it's already heavy steering, you want to try to get away with the least castor you can while still having self centring.

What I do as a starting point is set the threaded portion of the adjustable fulcrum pin in the middle of the threaded area. This will give you some castor.

Once you have the car on the road, go and get a proper wheel alignment. This will give you an accurate measurement and you will be able to see how the car handles with that setting. Depending on that you can then make adjustments.

To make life easier for yourself, don't fit the steel under bonnet splash shields until after you have completed the wheel alignment, as you will struggle to access the shims and pinch bolts for adjustment.

Additionally be aware that the only adjustment on the rear wheels is camber, which is adjusted using large shims between the hub and the driveshafts. When you initially assemble the spline into the hub coat the spline with a never seize compound to make it easy to remove the driveshaft if you need to.

[dlgis]

Thanks Andrew, I’m starting to get my head around the subject

[bitsobrits]

Hi, we’re about to start on suspension settings soon and according to the manual for the 3.8 Castor should be set at 2degs positive (+/- half deg). But what I wanted to check is where the 2 degs is measured from. Thanks

On my 4.2 S1 I found I could measure directly off the upright using the unused caliper mounting lugs on the front side of each upright, which in my case had machined flats which are parallel to the upright axis. Not sure if all E-type uprights are the same in that regard. Certainly caster can be measured using the camber differential method but it is much harder to achieve repeatable results in a home shop.

Using a magnetic digital level on the uprights I set them up with 3.0 castor in my shop then later had that verified and final adjusted by a pro shop. I was within .1 using the level. And no discernible increase in steering effort with the 1 degree increase in castor, even with 205 section tires, with much better straight line tracking.