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steering rack
dblissett - 9/10/03 at 07:47 PM

i am building a mcsorley 442 so do i shorten the sierra steering rack like mk or can i use the escort mk2 i am worried that the escort one might not be wide enough and so i will have bump steer
cheers dave

GO - 9/10/03 at 08:17 PM

you might well be ok, the escort rack is actually too wide for a standard width car - I think I'm gonna have quite noticeable bump steer

pbura - 9/10/03 at 08:31 PM

The +442 chassis is wider in the rear, book width at the front. Here's a good thread about bump steer with the Escort rack:

http://www.locostbuilders.co.uk/viewthread.php?tid=5983

With the wider car, book front wishbones will give you a front track 4-6" narrower than the rear, so you may want to look into longer wishbones:

http://locostbuilders.co.uk/viewthread.php?tid=7613

Best of luck,

Pete

[Edited on 9/10/03 by pbura]

GO - 9/10/03 at 08:39 PM

I thought the +442 was 4" wider at back, 4" wider in middle and 2" wider front?

JoelP - 9/10/03 at 08:45 PM

good thread that, just a shame the links posted in that one aren't working for me!

if you draw a piccy of the front of your car its easy to see where bump steer comes from. if the wishbones were the same length top and bottom, then it would be possible to make zero bump steer, except on a corner where the two joints are out to one side. i guess bump steer only matters on a corner anyway! With uneven length bones, due to the change in camber in compression and rebound, i think it is technically impossible to completely eliminate it, though with adjustment it will be unnoticable.

anyway, i got a shortened rack off MK, got some extensions made to make the length right overall, and it all seems to line up well. i cant see it being a problem on mine, provided i ever finish it...!

stephen_gusterson - 9/10/03 at 09:59 PM

I think you will notice bump steer in a straight line, possibley as a bit of a shimmy or lightness in the steering.

My car has a std rack and a bit more bump than id like, but not huge. I will find out what its like next year when its on the road.

atb

steve

kiwirex - 10/10/03 at 08:10 AM

quote:
Originally posted by GO
I thought the +442 was 4" wider at back, 4" wider in middle and 2" wider front?


I believe the +442 is +4 at the back (and middle), +4 at the TOP at the front, +2 higher engine bay.

Because the engine bay is +2 high, and the angle of the FU thingies is pretty much retained, the bottom of the front ends up a bit narrower than the book (I think) or close anyway.

I don't know if the +2 high is extended to the back bit (what letter is that now?).
It is extended down the side to where the scuttle finishes. He puts a tube on an angle from the scuttle to the angled bit at the back. (Man I've got to dig out the diagram and get those letters sorted). This probably has multiple advantages : making it a bit easier to get in and out, putting the triangulation right again with the upright bit

- Greg H

dblissett - 10/10/03 at 08:39 PM

the 442 is 4 inches longer 4 inches wider overall and 2 inches higher up to the rear arches i belive the angles are the same because its all in proportion
i hope
cheer dave