Rosejoints with or without camber adjusters (another boring debate)
Oval tubing etc
More details when I wake up
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]
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
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
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]
any one know a source of OVAL steel tube
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...
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.
quote:
Originally posted by mad4x4
any one know a source of OVAL steel tube
quote:
Originally posted by mad4x4
any one know a source of OVAL steel tube
ill get started on something... wont have it done for a wee while though, but maybe for summer...
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
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]
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.
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
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
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.
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
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
Ca you explain what modifications need doing exactly Matt as this is a " Let(s) design a solution!" thread.
quote:
Originally posted by mistergrumpy
Ca you explain what modifications need doing exactly Matt as this is a " Let(s) design a solution!" thread.
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.
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.
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).
Procomp LA Gold front-end...
This might help?
Here's one we discussed earlier!
Ah. I see all now. That big "X" brace does actually look a good idea. The longitudinal ones I have one of because of the bike engine, which seems to be omitted on CEC's. Cheers Scootz.
Thank you procomp I think you've just saved me a fortune, was going to bring my MK down to get it set up, but after reading the above I'd
only be wasting my money, the way I see your statement above is yes we can set your car up statically, but the moment you drive it on the road
it's going to flex that much that the work we've done will be of no benefit. thinking about it great way to make money but sorry if the
chassis is so shite I think I'll save my hard earned cash.
tony
if the chasis is so shite how on earth does it fare so well on the track ?
i dont see much difference ?
la gold
I built mine with around 7degrees caster and it centres pushing forward by hand, no chassis flex going on at 1mph although my chassis has lots of
extra bracing as it looked like a good idea at the time of build.
Last year I pulled out the rubber bushes and replaced with rose joints, with these in place I can twiddle the lower arms forward and pull the top
bones back easily, the offset washers allow plenty of flexibility here.
Of course you could always do what they did 30 years ago and locate the rear arm much further back then extending the rose joint makes loads of
difference.
Rescued attachment 1969_repco_brabham_bt-30.jpeg
Just have to make sure that lock is not compromised I guess.
Food for thought anyway, you could land this arm on the bulkhead junction and move the loads into the centre of the car.
[Edited on 28/3/11 by mark chandler]
My only concern with that approach (and i think it is a very good approach) is what happens in an accident.
Theoretically the wishbones fail first on a frontal impact, is there not a (low) risk of a wishbone spearing a driver / passenger. I do appreciate, if
the wishbones are contained at the front and fail, then there is a risk a wheel may hit a passenger. Just mentioning it for discussion.
quote:
Originally posted by snoopy
i dont see much difference ?
Is that a standard Indy? Doesn't look anything like any Indy's i've seen on here or at shows.
Is it the newer Indy R (if thats the name, sorry, not 100% sure).
mad4x4 - 29/3/11 at 01:37 AMLets keep the Chassis stiffining to this threadChassis stiffening
And keep this one on the Front suspension
scootz - 29/3/11 at 06:40 AMquote:
Originally posted by mad-butcher
Thank you procomp I think you've just saved me a fortune, was going to bring my MK down to get it set up, but after reading the above I'd only be wasting my money, the way I see your statement above is yes we can set your car up statically, but the moment you drive it on the road it's going to flex that much that the work we've done will be of no benefit. thinking about it great way to make money but sorry if the chassis is so shite I think I'll save my hard earned cash.
tony
That's not what Matt is saying Tony.
Take your MK to him and he will do as you ask... he'll either strengthen the front area of the chassis then address the set-up (recommended), or he will just set-up the suspension as best he can given the chassis as it stands (not recommended). Your call!
nitram38 - 29/3/11 at 06:51 AMquote:
Originally posted by mad4x4
any one know a source of OVAL steel tube
www.ralt.co.uk
whitestu - 29/3/11 at 07:19 AMquote:
That's not what Matt is saying Tony.
Take your MK to him and he will do as you ask... he'll either strengthen the front area of the chassis then address the set-up (recommended), or he will just set-up the suspension as best he can given the chassis as it stands (not recommended). Your call!
I'm sure that's right and that Matt is very knowledgable, but he comes across as having the opinion that anyone who has bought an MK is an idiot, which isn't going to encourage people to take their cars to him to get them sorted out.
Stu
procomp - 29/3/11 at 09:28 AMHi
I would just like to say that i have done nothing but try to point you guys in the right direction. I have very little time to spend on here at present as it's the start of the race season and I'm running behind with prep on cars that need to be ready to race very soon. I am not treating MK owners like idiots i am simply trying to help many make the best of the bad situation they find themselves in. I have no interest in comparing what i do with chassis compared to Mk or anyone else. Nor do i intend to try and start modding MK chassis to make profit. So lets get that sorted first.
The Mk chassis has no strength in the foot well bulkhead due to there being no tubes all the way across that area. The bent tubes that are there with deformed side walls are adding no strength and combined with the lack of any triangulation going forwards you are simply left with major flex in that area which is not allowing a stiff platform for the suspension to work from. As i described in the other thread you can flex the chassis by hand when pulling and pushing the front wheels. Cure this area first and allow the suspension to work from a stiff platform.
Cheers Matt
Davegtst - 29/3/11 at 09:49 AMquote:
Originally posted by MikeR
quote:
Originally posted by snoopy
i dont see much difference ?
Is that a standard Indy? Doesn't look anything like any Indy's i've seen on here or at shows.
Is it the newer Indy R (if thats the name, sorry, not 100% sure).
Thats not an indy R. Looks nothing like mine.
Frosty - 29/3/11 at 10:36 AMquote:
Originally posted by MikeR
quote:
Originally posted by snoopy
i dont see much difference ?
Is that a standard Indy? Doesn't look anything like any Indy's i've seen on here or at shows.
Is it the newer Indy R (if thats the name, sorry, not 100% sure).
Thats not an indy R. Looks nothing like mine.
No the picture posted is the LA Gold which is Procomp's chassis.
whitestu - 29/3/11 at 10:57 AMAdding in some additional chassis tubes doesn't seem very difficult if the payoff is as Matt suggests.
Stu
mad4x4 - 29/3/11 at 12:14 PMwere not knocking you expertise Matt. But some of our cars have been on the raod a while and I don;t want to strip the side panels off to weld in stiffeners. We should be able to get the steering better than it is so it at least meats SVA / IVA standards. At the moment mine does't even offer to self centre anything would be better than nothing
I went through all sorts of mods to try and get the rack to work better.
I eventually got through woth about 10 Deg of toe out and 45 psi in each tyre by the skin of my teeth.
Even a turnip in the greenhouse should be able to say .... well thats not right.
Yes strengthening the chassis may help but there seems to be something more fundamentally wrong.
If uncle RON can get it right on a match box surely we can get it right here.
Currently I have bought rose ends and weldments and plan either re-make the MK Arms or Modfiy the originals.
Frosty - 29/3/11 at 01:00 PMquote:
Originally posted by mad4x4
were not knocking you expertise Matt. But some of our cars have been on the raod a while and I don;t want to strip the side panels off to weld in stiffeners. We should be able to get the steering better than it is so it at least meats SVA / IVA standards. At the moment mine does't even offer to self centre anything would be better than nothing
I went through all sorts of mods to try and get the rack to work better.
I eventually got through woth about 10 Deg of toe out and 45 psi in each tyre by the skin of my teeth.
Even a turnip in the greenhouse should be able to say .... well thats not right.
Yes strengthening the chassis may help but there seems to be something more fundamentally wrong.
If uncle RON can get it right on a match box surely we can get it right here.
Currently I have bought rose ends and weldments and plan either re-make the MK Arms or Modfiy the originals.
But dumping a bucket-load of caster into the car doesn't automatically fix things. Caster does sometimes help with self-centring, yes. But self-centring is not the reason cars use castor.
Caster and KPI are responsible for the camber change when you turn your wheels from lock to lock. Turn your wheels on full lock and stand in front of your car. One of the weels will be on massive negative camber, the other will be on positive.
By altering castor, you'll be changing this behaviour also, so you can't just dump in a load of castor and think everything will be ok.
I would start with the easy stuff first. Remove the steering rack and make sure it's smooth in operation. Check for grease etc.