Well like a lot of people, one of my fail points for my SVA was 'no self centering steering action', so after looking through this forum, the easiest solution was to put some springs in the rack (I know various people will disagree, but thats the route I'm taking). Anyway got a hold of some valve spring (out of a Sierra Cosworth engine I think), and follows snoopy's drawing puting two into each side of the rack.

First problem was, on one side (left) the spring goes into the rack, but a little spacer should sort that out.

The bigger problem is the amount of lock I've lost, it looks like for lock to lock, will be 1.5 turns. That seem a lot more than a little lost lock (halving the original lock). So I think the springs I've used are either not compressing as much as the should, or are too long in the first place. I know some people have successfully used Pinto valve springs, but an anyone tell me the uncompressed/compressed length of these springs, or suggest a suitable alternative spring.

TIA.

Scott

I would have thought that big ole' red thing in your avtar would have self centered? Certainly most people that own them have no problems with being self centered

Sorry - couldn't resist!

Ooh good idea on the springs though - might just do this myself

*keeps eye on thread*

I went through all the options. In the end I remade my top bones to give me 7 degrees of castor.
Only took 2 hours to do and a day in the powder coaters.
Centers a treat. Glad I did it properly in the end.

This seems to work well... not ideal but if you see what i mean.

Can be altered back after SVA.


No offence Mark... but it works a treat! PICTURE

[Edited on 5-6-06 by Hellfire]

quote:

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Originally posted by Hellfire
This seems to work well... not ideal but if you see what i mean.

Can be altered back after SVA.


No offence Mark... but it works a treat! PICTURE

[Edited on 5-6-06 by Hellfire]

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if you search about a week ago I put up a how to make your indy self centre

you havent got to do anything different itll work fine

and ive explained it ok I think

quote:

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Originally posted by zxrlocost
if you search about a week ago I put up a how to make your indy self centre

you havent got to do anything different itll work fine

and ive explained it ok I think

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I dont understand why you MK boys have so much bother. My ZR flew thro the self centering test and isnt that far away from Mk geometry. My Dad built an MK locost (one of the early chassis) and got thro no bother.

Mushroom eccentric hole full forward. Neutral camber. Loads of toe out to the point where it looked wrong. Tyres 40psi. I drove there and back with 18psi though. Yes the car handled badly and care had to be exercised on the road (drive carefully and no liability accepted if you drive with these settings) but SVA was no problem. Self centering was plentiful. No springs in the std shortened Sierra rack.
After re-setting (ie normal toe in and 1deg neg camber) self centering has disappeared.

I remade my top wishbones to give 7 degrees of castor and what a difference self centering.I tried the springs first but lost way to much lock,took for ever to turn the car round.

I did mention about losing lock

but youve still got equivalent lock to a production car

dont know where springs were from there just valve springs

Ive done about 500 miles with testing and SVA and back etc etc absolutley perfect

although it will all be took of after

quote:

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Originally posted by DarrenW
...Mushroom eccentric hole full forward. Neutral camber. Loads of toe out to the point where it looked wrong. Tyres 40psi. I drove there and back with 18psi though. Yes the car handled badly and care had to be exercised on the road (drive carefully and no liability accepted if you drive with these settings) but SVA was no problem. ...

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quote:

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Originally posted by zxrlocost
I did mention about losing lock

but youve still got equivalent lock to a production car

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If you dont want to die, dont even think put springs to the rack.
The only way to fix the problem is ad more castor angle.
If you want a example of self centered direction, U can watches the front bracket of a bicycle.
I hope you excuseme to my English level.

Regards

[Edited on 5/6/06 by Maradona]

tried and tested thats good enough for me

and as above the inspector brings out all equipment now to measure toe out etc etc

why are springs going to kill me?
enlighten me

It would be an interesting discussion if the testers have got wise to the pressure and toe out 'fix'. i dont recall anything in the book about geometry settings, but seeing as the tyres can be bald i very much doubt hard new tyres are any less dangerous.

No discussion needed on here (hijack etc), just raising a point. At the end of the day i do accept that the testers have some lattitude ref whats written and whats not so it wouldnt surprise me, especially as we already recognise those settings are potentially dangerous on the road anyway.

And onto another point - what are the locostbuilders users names of the various UK SVA testers??????? i wonder if any of them have posted or just sit in silence in the background?

quote:

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Originally posted by Maradona
If you dont want to die, dont even think put springs to the rack.
The only way to fix the problem is ad more castor angle.
If you want a example of self centered direction, U can watches the front bracket of a bicycle.
I hope you excuseme to my English level.

Regards

[Edited on 5/6/06 by Maradona]

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quote:

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Originally posted by Hellfire

quote:

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Originally posted by Maradona
If you dont want to die, dont even think put springs to the rack.
The only way to fix the problem is ad more castor angle.
If you want a example of self centered direction, U can watches the front bracket of a bicycle.
I hope you excuseme to my English level.

Regards

[Edited on 5/6/06 by Maradona]

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Just a few supefluous adjectives there... let's not get over zealous!

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All I will say is that I am glad I took a little more effort to remake my top bones and ended up with a driveable car that needs no post sva modifications.

Ditto

Sorry, sometimes my English is bad and I lose some key word, I want to say that to make the direction self centrante it is necessary to have good caster angle.
I interpret, you are thinking to add springs to the steering rack, but again soory about my english

About the world cup, never your boys put us nervous, you have a good theam
we too. we will see what happens

Hmm he's not as nervous as the

REAL MARADONA going through customs

No self centering is a real pain on a long journey and a help when cornering. I have to believe MK never visit this site and no one has ever phoned or visited them to complain. It's just inadequate design and to still not have corrected it is grossly negligent.

My mate had the same problem on his Luego Velocity.

He got the suspension/camber/castor angles set-up correctly using some good equipment (just needs corner weights now) and it has improved the situation massively.

Agreed no self centering is a pain - especially in a RWD car where sometimes the quickest way to straighten up is to let go of the wheel completely - if you're getting a bit over zealous with the backend!

The whole idea of adding caster angle is to create self-centering WITHOUT toe-out, hard tires, springs, etc. Add in 6-10 degrees of caster (top bones 1/2" to 1" further back than the lower bones) and it will centre like it's supposed to.

make it right to start with, springs are a bodge of the very highest order, why do that then take them out and have a car that doesn't drive properly, you want self centreing for your own driving pleasure, not just to satisfy a crappy test.

So true he said it twice!!!

One left

One right

He's still trying to centre - but when he does

I have a Viento
Had very little self center and altered the caster fully, set the toe to neutral and it made a big difference.
The car will almost return to centre point on grass from full lock at 20 mph.

No need to over inflate the tyres

so maybe just messs about with the settings if you have somewhere to test it

I would like to know if the ones who have problems with self-centering measured their castor.

Did they really have 5.5 degr castor or more.
Or did the problem occur by the lack of castor?

I def. don't want to drive with springs, hard of soft tires, bad toe-settings or what ever.

So if 5,5 degr isn't enough what would be enough? Productioncars are not higher in castor than the locost.

I think is is mainly sierra hubbed car that have the problem, but stand to be corrected.

I am glad to see the symptom masking is being frowned upon, the SVA testers are fully aware of the bodging and probably investigate further

Apparently they are aware, as it has been said esewhere that some go so far as to feel/squeeze the gaiters and can fail you for dodgy extra bits. But technically as they can't see them they can't fail you for it. Part of why I want a complete floor.

MK should have sorted this by now

I can drive the car fast enough no probs without self centering so Im not too bothered.

Ive also passed it at the SVA which is all that matters

Ive done it simply for the test and it works so thats that

I measured the caster at my Indy, and it seems to be something like 7 degrees (not so easy to measure, but can't be too far off). That on its own should be enough. So as far as I understand, the caster on the Indy isn't the big problem. But what is?

By the way, I asked a friend with a Rush (Sierra uprights) to measure up his caster, and he told me it is about 12 degrees. That seems a bit steep, doesn't it?
Does anyone have comparable data from similar cars (sierra uprights) which do self-center? I know that the Striker does (but don't have the data). What about Tigers, Westfield SDV, GTS, Luego, MNR?!?!?

I definately agree that it requires a good solution. I hope to pass SVA with the tricks described here, but be honest; you want a good driving car in the end, and to 99% that means decent self-centering (amongst other things). So after SVA I want it sorted out, no compromises.

Maybe someone with the right capabilities should jump in and fabricate a correct working front suspension system which fits the Indy. I'd be interested...

The amount of self-centering you get is a result of the amount of weight on the front of the car and the amount of castor. A heavy car needs little castor; a light car like the Locost needs quite a lot.

David

mmmmmmmmmmm.........my car is lighter than a 7 as it is rear engined.
At 3 degrees castor it attempts to center. At 7 degrees it centers easily. So a 7 should center between 5-6 degrees.