Hi this is my first post so here goes. I have decided that I want to buld my own chassis, I have read the "book" and thought that I knew what I was doing until I read gregs post and your replies. So I suppose the main questions are: who/what are the Mcsorely plans, has anyone out there modded the "book" chassis to take seira bits (IRS, steering rack etc). I really don't want to start paying for fabrication bits that I could do myself -I don't care how long this build will take I just want hte satisfaction of doing it -I just don't know where to start

My chassis running gear is all sierra based apart from the steering rack.
If you wanted to use the sierra steering rack you would have to get it cut down too size as it is to wide to be used in a book chassis.
To be honest you would probably be better off getting a rack from Rally Design for about 50 quid as you'll probablyy spend the same amount getting a sierra one chopped/postage etc.

You can find the McSorley plans at http://mcsorley.net/locost/

These are effictivley the plans from the book but with the errors corrected, ie the front upright tubes for holdign the suspension brackets are in the wrong place in the book.

The only problem with this is if you want to use a sierra diff etc you will need a dedion tube to link the sides together, this you can either make yourself or buy from somewhere like GTS.
The main thing with this though is the rear of the chassis has to be kept flat rather than sloping upwards, this is to allow clearance for the dedeion.

Personally if i was starting again i would make the entire chasiss from the GTS plans as everything is then sorted for you.
You can buy these for about a tenner from www.gtstuning.co.uk (make sure you ring darren after youve sent paypal payment!)
GTS will also do the wishbones for sierra track width. however if you wanted to make these yourself im sure if you asked someone would give you the measurements you need.



The only other thing to watch for i think is that the sierra uprights needto have a new taper cut for the bottom balljoint, i think most of the kitcar companies that use sierra running gear could do this for you.

[Edited on 27/2/06 by Gav]

[Edited on 27/2/06 by Gav]

[Edited on 27/2/06 by Gav]

arent the Rorty plans great too for using IRS setup with a sierra diff?? instead of dedion, but might be quite difficult to build. i'll go IRS as i guess it's what the sierra diff has...

so if i get the GTS plans, will that be much better than Mcsorley to use sierra bits?
do i have to ring darren? im in spain....

I've not really looked at Rorty's IRS plans so i dont know, im just relaying what i have learnt.
imho dedion is the simplest way to get a working rear end rather that the hassle of IRS

As for the GTS plans their are two varients im aware of the standard one which i used and is 'bookish' dimensions and the wide version which is +4 inches, both of which i think are ok for sierra track width, the wishbones are just longer for the smaller width chassis.

And yes i'd ring darren to make sure you get the plans

cheers lads I'll give them a ring

I am part way through the build of a slightly modified rorty IRS back end drawing are great details good and the design straightforwartd to build. Only problem is that it is for a standard width so have had to alter design to suit sierra half shafts

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Originally posted by dnmalc
I am part way through the build of a slightly modified rorty IRS back end drawing are great details good and the design straightforwartd to build. Only problem is that it is for a standard width so have had to alter design to suit sierra half shafts

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Basically the set up in rortys design is for a standard width locost as I am building a +4 one has to make the decision either to increase the distance between the pivot points for the wishbones by 4 inches or to extend the length of the wishbones. either way the roll centre of the rear ewnd is disturbed but by keeping the wishbone length the same the effect is to move the instantaneous centre of the body relative to the wheels further out by 2 inches. This makes a marginal diference in the roll hieght but I concluded that it was not suffiecient to have any significant effect. Also by keeping the bones the same as before I have assuned that castor, camber and the bumps steer (asuming that I end up with some toe in )will remain almost unchanged.

how have you got on with this?

im pretty sure you leave the pivots points the same from the centreline, also the wishbones stay the same length.

with a +4 chassis, all you are doing is moving the oter rails out by 2" each side.

The Rorty IRS plans are for standard sierra track are they not?

correct me if i a m wrong, just trying to get my head around this...lol

The 7+4 is 4" wider down the width, however the 7+442 is only wiser at the back, the front ends up being the same as the book chassis. This is the route Im taking but havent got as far as the wishbones yet and was just going to deal with the dimensions when i get to them (unless of course anyones got any plans for the +442 wishbones using Sierra uprights)

My build has stalled due to other projects at the moment (hopefully for not too much longer) so I haven't looked at it again - I was under the impression when I downloaded the plans from Rorty that they were for standard Sierra components. I guess I will find out eventually. Unless the new book is out before that stage and I use that instead!

Would you recommend a 7+4 or a 7+442 build instead of the standard design to someone that is 1.90cm x 14 stones and prefers to drive in a `Finnish` position?

cheers, Yiannis