Thursday 29 March 2007

Up to the front ... Continued

I have still been thinking about how stiff the suspension is. I hadn't really got any helpful replies from the Cobra Club forum so I decided to build up the other side. I made sure that everything that should be greased was greased and assembled as before - the result was pretty much the same. I had improved things slightly by adding another camber shim. The original donor parts had 3 shims each 1.6mm thick - total 4.8mm. For some reason I had but back four new ones each 1.0mm thick. This results in the upper wishbone arms being 0.8mm closer together and therefore distorting the bushes slightly. So I added another one which makes things 0.2mm over size - much closer. (4 to the front 1 to the back).
I am now two short for the other side so I need to order some more!

I had therefore concluded that things should be this stiff - I'll just have to slacken the nuts to check the bump steer - more on that later.

Having checked the camber of the off side hub the next thing was to check the castor. This is why I haven't fitted the front callipers yet. The hub carrier has two lugs where the brake calliper fits (see below)
These lugs have a machined flat on them so that the two flats represent a line parallel to the steering axis. So measuring the inclination of the these lugs will give the amount of castor. I did this using a homemade template I knocked up on Autocad:You can see that the off side castor is exactly 5 degrees (measure with the top wishbone horizontal). This should be OK but can only be confirmed with a test drive - so that'll have to wait then!

If this may be of any use then click on the image below for a copy - print it out and stick it on a piece of MDF and used some black cotton with a plumb bob.
So I need to order a couple more shims before I can complete the near side and check the set up there.

It's starting to look like a car now (if you squint really hard!)



7 Comments:

David McNiff said...

Excellent tool :) It looks fairly accurate - couldn't this be used as a camber tool too? Would save forking out £40 for one...

STR said...

It only works for caster because of the two machined reference flats on the caliper lugs.

To use as a camber tool it would need to be modified to clear the centre of the hub to use the top and bottom of the disc as reference points. Caster needs to be measured a bit more accurately and with the magnetic base you couldn't do it much easier.

It's only 40 quid after all :)

David McNiff said...

thanks--- got one from ebay for £20 - bargain :)

I'm sooo jelous that you are driving it... will see you at a meet :)

STR said...

Hi G,

Where are you based and what are you building??

Cheers,

Simon.

David McNiff said...

I'm in Darlington, building mk4 gd. Stage: have chassis with rear axle complete, one side of front suspension on - ready to set camber/castor. Saving up for body and going through engine choice dilemma... you know - you've been there...

STR said...

Ah-Ha.....

That'll be Daveymusso then?

If it is I'll pm you later on the forum.

Cheers,

Simon.

David McNiff said...

thats me :)