front axle settigns (camber, castor, toe)

[Sportster-Green]

Maybe somebody can help me with explaining the actual settings on my sportster:

i guess its the first sportster Marlin built still using Ford components:
Hubs are Cortina or Granada
Upper wishbones have adjustable eylets for setting caster and camber.

Actual settings are negative camber and clearly visible toe-out. unfortunately i have (acutally) no values for caster
the coilovers are mounted correctly (not upside down as on the picture).

usually on my (other) kitcars i could always set toe to zero or slight toe-in

if i do this on my marlin the car is not controllable and extreme nervous..i´ve tried it once and did not even drive more than 20m until i turned around.

what causes the toe being set like this, or lets ask differnt:

why my car gets so nervous and undriveable when toe has been set to zero.

here a pic of my front (parts look clean and tidy in the meanwhile, and not so scruffy as on the pics)

DSC04399.jpg

[copperleaves11]

Re: front axle settigns (camber, castor, toe)

Hi. I too have the same set up and from memory I think zero to 3mm toe in is about right. However the castor setting is fairly critical. The adjustment is made by altering the position of the spacing washers on thetop wishbone pivot. On mine there are approx six washers in total and I've found that 4-5 at the rear of the upright and 1-2 at the front is about right. My car has not got a lot of self-centring but it feels good with no bump steer or tramlining issues and tyre wear is dead even. Regards David.

[Sportster-Green]

Re: front axle settigns (camber, castor, toe)

hi and thanks for the reply.

hmm..i think you got me wrong:

my car is set with toe-out and if its set to 0 or slight toe-in its undriveable....and i´m trying to investigate why.

castor on my car can be set, as already stated above (and visible on the pic) by adjustable elyets where the upper wishbones are bolted to the chassis.

[Mike]

Re: front axle settigns (camber, castor, toe)

Hi Axel

If you are having problems with zero front toe, I think you must have some serious suspension setting issues.

Have you checked the rear wheel toe? It is common on Cabrios (the Ford Sportster had the same suspension as the Cabrio originally) for the rear toe to be a long way out from where it should be. I believe Derek Jones had one side which was significantly out.

Independently I have been advised a small amount of rear toe in (2mm on 16" rims) helps make a car more stable.

Then as Dave Siddall has stated the Castor is important to allow the steering to self centre. But when set up correctly some degree of toe in should be achievable/desirable.

The following was a recommended as a good set up for a Cortina front, Sierra rear by Gerry Haines (sadly died last year)

Front
Castor : 2 degrees
Camber : 0.5 degree
Toe In : 3mm

Rear : Toe in 3mm
Camber : - 0.5 degree

[Sportster-Green]

Re: front axle settigns (camber, castor, toe)

thanks for the values...and a good advice also searching at rear....


the rear on my car is fully adjustable.

what i must add:

the car came to me with toe-out, the steering wheel is in the centre, the steering is precise, self centering present, it drives straight on flat roads, but feels kind of nervous on un-even surface with lots of bump-steer.

as it was marlin´s ex-factroy track car, it might be set a bit different than a normal road car.

by the way: here a pic of the rear suspension:

marlingvisit42.jpg

[Mike]

Re: front axle settigns (camber, castor, toe)

Hi Axel

You are on your own with this one! This is totally unique!

The rear trailing radius arms are Marlin's own for racing.
The chassis mounts look like they are the standard Sierra mounting positions, so you could replace the racing trailing arms with standard Sierra ones, but you will lose the ability to make easy adjustments.

As you say, it is very likely they will have set the car up very differently for racing compared to a road car.

I guess your car is quite stiff with anti roll bars front and rear?
By the time they were selling the last of their Cabrios (same chassis as your Sportster) they were suggesting anti roll bars were not necessary front or back for road going cars - and even supplied mine with the front anti roll bar with the middle cut out!
(I have since changed it to the lighhtest duty Ford Sierra anti roll bar - and I know other owners who have reduced their anti roll bar to the minimum diameter bar, and found it made the ride much more compliant.

Your anti rioll bars would be quite easy to disable and test without completely removing just to try it out?

Good luck!

Mike

thanks for the values...and a good advice also searching at rear....

the rear on my car is fully adjustable.

[ATTACH]4701[/ATTACH]

[Sportster-Green]

Re: front axle settigns (camber, castor, toe)

yeah i could disconnect the drop links from the arb and see (feel) the difference....good idea!!

interestingwise i´ve also a westfield seven in my garage...i´ve driven and owend certain of them...but this one is the first with a retrofitted front anti rollbar.(original westfield one, mounted exactly like the facctory equoipped cars)

in the past i always said: with such low and stiff cars its not necessary to install an ARB...but i was wrong: the actual westfield feels so differnt and so much improved against all others i´ve driven before.

ok...back to my marlin:

its not really stiff...the typical seven type cars i´ve owned and driven have felt much more harsch and stiff than my marlin.

the only thing i dont like on my marlin is, as said above, that the steering is kind of nervous on a usual (and bit un-even) road.

with the behavoiur of the rear end i´m quite happy (has enough rip, no tendency for extreme or quick oversteer...even the car has a tuned rover v8 fitted)..driving on a track is pure fun...driving on normal roads is a bit more tricky....not too bad... but i feel that it could be improved.

[greyV8pete]

Re: front axle settigns (camber, castor, toe)

................................. the only thing i dont like on my marlin is, as said above, that the steering is kind of nervous on a usual (and bit un-even) road.............

Having the incorrect wheel offset (compared with the O/E donor set up) can give those symptoms. Maybe worth checking yours and comparing with other Sportster owners? Peter.

[Sportster-Green]

Re: front axle settigns (camber, castor, toe)

when i bought the car it was equipped with 2 set of wheels, those 2 sets came already with the car when it was sold from marlin to the owner b4 me: ones with semi slicks, the other ones with road tyres. those are fitted now.

both have the following dimensions:

7x16, ET 35

tyres are 225/50R16 V

[nigel]

Re: front axle settigns (camber, castor, toe)

Back to the front suspension, I seem to remember that as a general rule you should use toe out with negative camber and toe in with positive.

Increasing castor will improve self centring and stability, but too much will make the steering very heavy.

I am running approx. -1.5 degrees camber 4.0 degrees caster and 2 degrees toe out. That works for me. It's stable in a straight line with very positive point and shoot steering. I'm also running about one degree of toe in at the rear.

But before any of that the fundamental thing is to check all the wheels are pointing in the same direction and are parallel to the chassis centre line before you start adjusting anything!!

[Sportster-Green]

Re: front axle settigns (camber, castor, toe)

Back to the front suspension, I seem to remember that as a general rule you should use toe out with negative camber and toe in with positive.

!

that sounds logic.....as i have a similar front-setup on my (live-axle)locost, which was formerly used as a track car.

what concerns me a bit (on both cars):

if i change the tracking by half turn each side on the steering arms (e.g. more toe in or more toe out) it has an immediate influcence from formerly driveable into almost undrvieable. (to repeat: half turn each side only!!!)

on my sylva, which is set to -0.5 camber and 0 toe-in...you need 2 or more turns to the tracking to get a similar (neg.) effect to the drivability.

[nigel]

Re: front axle settigns (camber, castor, toe)

if i change the tracking by half turn each side on the steering arms (e.g. more toe in or more toe out) it has an immediate influcence from formerly driveable into almost undrvieable. (to repeat: half turn each side only!!!)

.

What castor angle are you running.

I believe that if you have very steep castor angle (eg,<1 degree) the front end will be very sensitive to front wheel geometry.

Try to relax the castor angle by removing any washers at the rear of the top wishbone and transfer them to the front and see what happens.

(A track car would typically have a more aggressive castor angle ie. more upright, to improve steering response)

[Sportster-Green]

Re: front axle settigns (camber, castor, toe)

i haven´t measured the castor angle yet.

for changing castor i do not need to move washers, my upper wishbone eyelets are threaded and screwed into the wishbones (see pic on first page of this thread)....hopefully this makes things easier??

[nigel]

Re: front axle settigns (camber, castor, toe)

You could do that. Unscrew the front eyelet and screw in the rear one will increase the castor angle, but it will also alter the camber.

If you simply slide out the top wishbone pivot pin and alter the number of washers at the front and rear of the eyebolts (more in front of the front eyebolt and less behind the rear eyebolt) that will increase the castor angle with no discernable change in the camber. You'll probably find that a lot easier and quicker to do without the hassle of trying to balance the castor and camber angles when you have such a coarse screw thread on the eyebolts. I remember it well. A few things got kicked and others thrown around the garage when I was trying to do it...................!!

Nigel.

[nigel]

Re: front axle settigns (camber, castor, toe)

You could do that. .

And as an aside, don't worry about measuring the castor angle at this stage.

Just get as much castor as you can (within reason) set some neg camber and then see how the car responds to changes in toe.