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Author: Subject: self centering fix for MK Indy? - Let design a solution!
mad4x4

posted on 27/3/11 at 02:01 AM Reply With Quote
self centering fix for MK Indy? - Let design a solution!

We all no the problem - Lets keep the other thread for the debate on try this try that etc.


Can anyone on here help re-design the MK Top Front suspension arm?

A the moment I see squash u-shaped tube (oval steel) with a Transit ball (IIRC the top bJ is transit) joint mount in the middle of the U and 2 x Threads for Rose joints at the other end.

So we need

1) Grade of Steel and Size

2) Transit Balljoint Weldment (threaded tube) is this M18 or M18 Fine ? Left or RIght
this guy does them

3) 2 x Rose Joint Weldments (Threaded Tubes) this guy does them

4) Lets base the disign on the MK indy top with the ball joint moved back 25mm but kept at the same kick up angle

5) We need the distance (center to center of the chassis pickups on the MK INDY in mm

6) We need the dimensions of the INDY's current arm

7) A drawn Cad drawing


8) Some one to Mock up 2 as per Cad drawing


I'm not back in the UK till April 2nd so can't measure my own one

[Edited on 27/303/11 by mad4x4]

[Edited on 27/303/11 by mad4x4]





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MK INDY's Don't Self Centre Regardless of MK Setting !

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Ben_Copeland

posted on 27/3/11 at 03:56 AM Reply With Quote
In the process of having a trial set made

Rosejoints with or without camber adjusters (another boring debate)

Oval tubing etc

More details when I wake up





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Triton

posted on 27/3/11 at 05:13 AM Reply With Quote
On the cards but what will be on offer is a bit more than just wishbones, the aim is to dump the Sierra uprights as well as they are pants





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ReMan

posted on 27/3/11 at 09:28 AM Reply With Quote
I never liked either the bent tube or bent oval tube upper bones, for the simple reason that IMO they looked pants as they didnt match the lowers.
So I bought a pair off GTS and they arrived !! and I fitted them as per the poor pic. Unfortunatly I think they missed a trick at the time in as much as these are exactly the same geometry as the originals.
Surely these, with an appropriate change in dims would be the easiest to make too?



[Edited on 27/3/11 by ReMan]





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mad4x4

posted on 27/3/11 at 10:18 AM Reply With Quote
any one know a source of OVAL steel tube





Scot's do it better in Kilts.

MK INDY's Don't Self Centre Regardless of MK Setting !

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JeffHs

posted on 27/3/11 at 10:32 AM Reply With Quote
My book built pinto-engined car with book wishbones and Cortina uprights was horrible to drive and failed SVA on self-centring. My solution (bodge?) was to piggy back another piece of 25 mm RHS at the rear of the chassis upright so that the top brackets could be moved 25 mm rearwards, retaining the original wishbones. I had to remake the side panels too.
Sself centring was fixed immediately, handling was still horrible until I positioned the steering rack much higher to mimimise bump steer. Finally I experimented with tracking and now it's a pleasure to drive, could still be improved but it's good enough so I haven't got around to it yet.
In my opinion, it is not realistic to make nice-looking round tube top bones as per book design with enough offset to fix the inherent design flaw in the top mount position. To do so you would end up with some very awkward angles where the tubes meet the inner and outer ends, and again in my opinion the weld area would be compromised.

In short I think there are 3 options

1. Move top mount rearwards and retain original classic-style wishbones
2. Use bent tube wishbones which look awful (IMO)
3. Use rod ends to change the angles. (is this sound engineering?)

I realise if you've bought a chassis and don't feel like hacking it up and re-welding, then option 1 is not going to appeal, but...

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David Jenkins

posted on 27/3/11 at 10:48 AM Reply With Quote
quote:
Originally posted by JeffHs
In my opinion, it is not realistic to make nice-looking round tube top bones as per book design with enough offset to fix the inherent design flaw in the top mount position. To do so you would end up with some very awkward angles where the tubes meet the inner and outer ends, and again in my opinion the weld area would be compromised.



I managed it with no problems whatsoever! - The angles don't change dramatically, just 2 or 3 degrees added on one place and removed from another.





The older I get, the better I was...

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ReMan

posted on 27/3/11 at 10:57 AM Reply With Quote
quote:
Originally posted by mad4x4
any one know a source of OVAL steel tube

MK?





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Neville Jones

posted on 27/3/11 at 11:15 AM Reply With Quote
quote:
Originally posted by mad4x4
any one know a source of OVAL steel tube


It's called 'flat sided oval', sold by Hub le Bas last time I need some.(Definitely NOT for car wishbones.)

Cheers,
Nev.

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A1

posted on 27/3/11 at 12:10 PM Reply With Quote
ill get started on something... wont have it done for a wee while though, but maybe for summer...
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whitestu

posted on 27/3/11 at 12:11 PM Reply With Quote
Using rod ends to modify standard MK top bones easily gives >6 degrees of castor. As the rod ends are much thinner than bushes the bones move back by about 25mm and the rod ends can also take a bit of angle.

It is a dead easy modification, but costs about 60 for the bits and pieces.

Stu

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mad-butcher

posted on 27/3/11 at 04:46 PM Reply With Quote
Be very carefull unless you want to make a tit of yourself and destroy your business. I've asked many an engineering company on here if they could make a set for me, the answer was no (only Wozsher picked up the challenge and a great job he made ) one was completely honest with me and said not a Fcuking chance. if I get it wrong and it don't work the slagging commitee will be out in force and then I've lost my reputation .


[Edited on 27/3/11 by mad-butcher]

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Neville Jones

posted on 27/3/11 at 05:02 PM Reply With Quote
I'd offer to make the wishbones, BUT, from experience, the positioning of the wishbone mounts on the chassis, and the chassis itself, need to be on hand to make sure that the PROBLEM is being addressed properly, and not just the symptom.

A decent set of wishbones, on a wonky chassis, with incorrectly placed chassis mounts, will give the same problem as wrong wishbone geometry. It's a total problem by the looks of it, not just a wishbone thing.

MK are not the only company with these problems, and every manufacturer should be sorting this problem out.

As has been said before, this has been around for far too many years, and should have been addressed by all manufacturers many years ago.

Cheers,
Nev.

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Hellfire

posted on 27/3/11 at 06:18 PM Reply With Quote
Nev, you say that MK are not the only manufacturers with this problem. Who are the others? Can we assume that Caterham and Westfield have got it right or do they have issues too?

Phil






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mad-butcher

posted on 27/3/11 at 06:18 PM Reply With Quote
Nev
Nice of you to admit it's not just MK that have this problem, I was begining to think you had it in for MK.
I have 2 and would have no hesitation buying a 3rd as I feel MK represents good value for money.
I have no idea what the politics behind Snoopy ( Charlie ) leaving the company were, but from reading posts on here about customer services I think he is sorely missed.

tony

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Mark G

posted on 27/3/11 at 06:31 PM Reply With Quote
My Indy failed the SVA for no self centering.

To fix it I just removed the rack as it was stiff to turn with the wheels off the floor. Stripped the rack apart, Cleaned, re-greased, adjusted the pinion and refitted the rack to the car.

Problem solved, no wishbone modifying required. It turns out that the 'modified rack' that MK supply isn't actually reconditioned or even checked before they hand it out.

I know that all cars are different, that's just how I fixed mine.

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Neville Jones

posted on 28/3/11 at 11:58 AM Reply With Quote
quote:
Originally posted by Hellfire
Nev, you say that MK are not the only manufacturers with this problem. Who are the others? Can we assume that Caterham and Westfield have got it right or do they have issues too?

Phil


I won't single any one out as good or bad. I've 'adjusted' them all, including the kits from Surrey and Dudley. The worst are a couple of the 'M's', two of which are particularly outstandingly variable.

They all need to throw away what is in The Book, and based on 40 year old technology, and reconfigure from scratch to suit current thinking. (And not what you read in Staniforth, either!)

Cheers,
Nev.

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procomp

posted on 28/3/11 at 12:19 PM Reply With Quote
Hi

The one thing that seems to be being completely over looked as i tried to point out in the other thread is the actual chassis. If you do not get the front chassis to stop flexing from the bulkhead forwards you will never get the Castor to take effect because the chassis physically wont allow the effects to happen. It simply does not allow the extra weight to be placed upon the inner wheel as the chassis just flexes and allows the weight to be tranfered back to the outer wheel. You have to get the strength back into the bulkhead and then strengthen the front chassis. If you don't you will only get the same results as per Hellfire who has modded the wishbones. Bugger all difference.

Address the chassis first then the other issues otherwise your wasting time and MONEY.

Cheers Matt






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mistergrumpy

posted on 28/3/11 at 01:45 PM Reply With Quote
Ca you explain what modifications need doing exactly Matt as this is a " Let(s) design a solution!" thread.
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scootz

posted on 28/3/11 at 02:37 PM Reply With Quote
quote:
Originally posted by mistergrumpy
Ca you explain what modifications need doing exactly Matt as this is a " Let(s) design a solution!" thread.


That's Matt's livelihood. I'd doubt he's going to publish a detailed 'how to' on the subject...

[Edited on 28/3/11 by scootz]





It's Evolution Baby!

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mistergrumpy

posted on 28/3/11 at 02:50 PM Reply With Quote
I see what you're saying but are we talking stregthening it longitudinally or laterally. I'm just struggling to understand what he's trying to explain. I suppose a look at a Procomp chassis would reveal the answer I'm after.
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40inches

posted on 28/3/11 at 04:15 PM Reply With Quote
quote:
Originally posted by Mark G
My Indy failed the SVA for no self centering.

To fix it I just removed the rack as it was stiff to turn with the wheels off the floor. Stripped the rack apart, Cleaned, re-greased, adjusted the pinion and refitted the rack to the car.

Problem solved, no wishbone modifying required. It turns out that the 'modified rack' that MK supply isn't actually reconditioned or even checked before they hand it out.

I know that all cars are different, that's just how I fixed mine.

Yep! mine didn't have any grease in it, I fitted a grease nipple to the centre section.

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MikeR

posted on 28/3/11 at 04:23 PM Reply With Quote
I'm no engineer but ........

I'd start with adding a diagonal in the engine bay from the top of the footwell by the gearbox to the outside where the front u section meets the tube that the wishbone mounts on. If you can add one each side (but also be aware that if you're in a crash you've now got a large section that won't deform as easily).

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scootz

posted on 28/3/11 at 04:31 PM Reply With Quote
Procomp LA Gold front-end...







It's Evolution Baby!

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sebastiaan

posted on 28/3/11 at 04:44 PM Reply With Quote
This might help?

Here's one we discussed earlier!

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