I am thinking of making some new wishbones for my tiger cat (getting rid of the sierra TCA in the design). I intend to make some like the F27 (bottom wishbone picture from gref27's archive). Means I can widen the front track at the same time too.

Just one question

Does the taper on the M18 transit drag link fit the sierra upright (bottom).

thanks



[Edited on 4/1/08 by givemethebighammer]
Rescued attachment wishbonethreadedinsert sml.jpg

The Transit drag link doesn't work as a ball joint on a bottom wishbone - it wasn't designed to work like that and isn't nearly sturdy enough to be used as an acceptable bodge....... A 'rose' joint is far from ideal as well.... a spherical bearing is what you want but that will need a bit more engineering than something you just screw in. .....

I was thinking about the way the drag link would get loaded if used like this. I going to have a rethink and design something to utilise a proper bottom ball joint. Which ones fit the sierra uprights (correct taper) without having to modify it cortina ? Maxi ?

thanks

[Edited on 5/1/08 by givemethebighammer]

Are you keeping the rocker arm set-up on the top? If so, the Transit type drag link will work fine, as it does on an F27. The Fury/Striker etc used a Sherpa one - it may have some advantages such as range of movement, but size wise it is pretty much the same as the Transit.

You just need to find out if the tapers match. Maybe someone here building a car with Sierra uprights can tell you??

Cheers

Fishers modify the sierra hub to take the Sherpa joint. I don't know if the Transit requires the same though (so thats not a lot of help!!!).

adrian

Yes I am keeping the top rocker arm set up. I was thinking of getting an extender (like a steering rack extender from MK) about 50-60mm long to allow me to widen the track width. I'm just thinking about how the joints are going to be loaded and whether the extra 50-60mm will put too much strain on the top transit drag link or the rocker arm. I realise that I may need to change my springs though. The desk is just a mass of sketches and measurements at the moment.

Think carefuly -- using a TCA and compresion strut to form a wide based lower wishbone actually has a few advantages over a conventional wishbone.

The disadavantages of the Sierra TCA is that it has lump of rubber in it between the compresion strut and the TCA that allows movement under braking and it just looks a bodge.

quote:

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Originally posted by britishtrident

The disadavantages of the Sierra TCA is that it has lump of rubber in it between the compresion strut and the TCA that allows movement under braking and it just looks a bodge.

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quote:

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Originally posted by givemethebighammer


Exactly, and I want to widen the front track of my car, which just isn't going to be possible using the TCA.

Just finishing the diagrams now, I've settled on 4 degrees of caster in the design. Just need to get some 25mmx3mm CDS and some 30mm I/D tube to make the eye tubes from. Anyone know a good steel stock holders near Loughborough as Adey's Steel are so expensive!

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I'm not sure I fully understand british trident. The rose joints at the inner ends yes but not the compression strut. Any chance of a quick sketch ?

thanks

Just do what the Escort people do, make an adjustable TCA by cutting it in half and welding in a heavy duty threaded adjuster (available from Rallydesign etc.). Provided it's done properly you have an automotive grade balljoint to connect to your upright, and your choice of either metalastic bush, polyurethane bush or rod end on the inboard end and you have easily adjustable camber.

quote:

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Originally posted by givemethebighammer
I'm not sure I fully understand british trident. The rose joints at the inner ends yes but not the compression strut. Any chance of a quick sketch ?

thanks

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Rescued attachment tca1.GIF

That's pretty much what I was thinking of doing. A few pictures would be great though.

thanks

look at the top wishbone on this Lola
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mclaren m10
Rescued attachment m10a03pb..jpg

Right, gmtbh, I have some 21mm OD x 3.2mm wall CDS at home that you are welcome to if its any good. (I use it for wishbones)

For steel I usually use NSI in nuneaton for sheet and welded tube, JPL Steel Stock in Thrumaston for bar (they do offcuts for cash and have all sizes of bright drawn in nice grades like EN24T and EN16.

I have found Adey ok on price though as well, steel's just expensive now!!

You can also replace the bushed joint in the middle of a sierra tca with a solid pivot, it's part of a compression or tension strut kit, I made one for sierra tca's years ago when I built my old rally car (rwd pug 205) that used cossie uprights on the front with solid compression struts, adjustable tca's and no anti-roll bar.

I might even have a pair of adjustable tca's for a sierra laying about, pretty sure I have in fact.

Here you go:




the links at the top end of the two bars in the piccy sandwich into the normal antiroll bar rubber bush seats in the middle of the std tca, thus the bars then replace the antiroll bar in locating the tca's. The brackets in the pic weld onto the mk2 escort (or sierra, rally design do kits to suit both) chassis rails.

This all effectively makes an adjustable wishbone as britishtrident was suggesting.

I can show you how to do it as I have done these a fair bit before.

Thanks guys, I already have adjustable TCA fitted (cut and welded with an adjuster in). I really want to go for a cleaner look with a wider front track. The way that top wishbone on the Lola is constructed looks good, how is the ball joint fixed into the tube (pressed in ?).

Nat thanks for the offer, could you drop me your mobile on U2U as I wouldn't mind a chat about this when you are not busy. You are right about the price of steel these days. The place I used to use in Derby was even weighing in the sweepings off the floor!

I think the Lola used circlips and a spherical bearing -- similar to the current Caterham.

ISTR some kit uses BL METRO ball joints the non-adjustable type.

[Edited on 7/1/08 by britishtrident]

Thanks BT

Is this really just pressed in ?

http://wiki.seloc.org/a/Change_a_ball_joint

I can't see where they might have removed a top circlip