Please could someone help me with some info to setup the bottom wishbone brackets.

I've made up a jig and combined with running threaded bar through each pair of brackets it should be easy!


The top four brackets fit perfectly but the bottom pairs are about 6mm (each side) too wide to sit on the LA/LB rails.

According to The Book and another diagram on here the centre points of the bottom two pairs should be 418mm apart.
My jig is setup so that this is the case.

I've double checked the LC and LD rails and mine are correct to the book.

So, I'm left with the following dilema- either LC and LD are wrong in the book or the diagram/figures of the bracket positioning (418mm apart) is wrong.
or my ruler is elastic...

Any help greatfully recieved!

Thanks,

James

According to my calculations from the book the centres should be 343mm minus the width of one of your bush tubes. If you have made your wishbones according to the plans this will be 307mm. I fitted mine to the wishbone and clamped them in place then tacked them to make sure they worked then measure from them to fit the top ones. You can't use a threaded bar because one of them is behind the dreaded FU1 or 2 tube.

yours, Pete.

I have a cad of my dimensions dood.. mega different




[Edited on 2/6/03 by Hornet]

I found this, and did two things to combat it, put a piece of 3mm plate under the rear brackets which means you need to raise the front ones 3mm also, which closes the gap a little, I then put a piece of 3mm plate behind each of the front brakets, which made it a nice snug fit.

BTW, if you leave FU1&2 off, until after you've attached the bottom brackets, it mean you can use bar, and it makes putting top ones in the right place far easier.

Kingr

Thanks for the info peeps- keep it coming!

In order of reply:

Pete,
I'm being thick (nothing new) but not quite sure what you mean by the figure of 343 as I can't see that this isn't a tad too small! Or is this to do with the width of the wishbones?
You're right about the bar with FU1/2 tho!

Hornet,
You're right- very different.
Your diagram was the one I used initially to make my jig. Have you actually fitted you brackets with it? It's just that I found it was far too big (both 614mm and 430.95) and when I went back to the book plans the top atleast fitted perfectly (using 594mm not 614) and the bottom was a lot closer.

Kingr,
I played around with that idea last night and this would work almost perfectly- I just wasn't sure whether there were strength issues with this.
Fitting FU1/2 later would have been a good idea- but I was keen to get on with Cymtrics' mods so did them awhile ago.

Thanks eveyone- anyone else got any info?


James

You mean the distance across the front and I was thinking of the sides. If your measurement across the front is different to the book it will not affect anything as long as they are level from side to side and square from front to back. I used packing and a pair of spirit levels when I did mine then clamped and tacked them, probably not fussy enough but I have done enough write offs to realise that in the real world 2mm is not going to make much difference to my driving.

yours, Pete.

Right, I must be feeling keen as I nipped home at lunch time (only an hours drive for 1 hour car work!).

First thing I did was fit a 3mm plate under the lower rear brackets which brought the front brackets 1-1.5mm (guesstimate!) closer to LA&LB.

I then fitted a 3mm plate between the front lower brackets and LA&LB and this fitted almost perfectly.

So, if I don't come up with any other way of doing it does anyone see a strength/safety issue of doing it this way?

Thanks,

James

P.S. Hornet, sorry to appear to be ignoring your CAD work. As I said before I built my jig to those dimensions initially and the brackets were completely out!

Well, others may have a more authoritative answer for you, but I can't see why it would be any weaker, most of the forces going to be trying to pull the brackets almost directly away from the chassis, which as long as your welding is up to scratch, having 3mm plate sandwiched in should make any difference to. The biggest effect of having 3mm plate in there would my make that I can think of would be 3mm of extra leverage when twisting the bracket around the chassis member, but the wishbones should prevent that ever happening. Incidentaly, the brackets on tiger avons have the holes a few mill further from the base anyway.

Kingr

NS James
I simply put dimensions, angles of steel and brackets in, the CAD then gave the dimensions.. not me.
My brackets have been fitted to a standard chassis and fit perfectly.
the only difference is i chopped the necessary 25mm off the length of j1 and j2 to give correct castor.
Hope this helps

Gave this matter further thought James.... book dimensions are based on brackets I think with holes 20mm from base. My brackets were bought and are 25.7mm from base. This is why my dimensions differ greatly. If you wish i can do a cad of yours so that you can double check.....
cheers