steering rack height

["Barry Dickinson&quo]

Does anybody out there know the correct height of the steering rack mounting
for an S4 Elan. No measurements seem to be given in the Workshop manual. I
use the car mainly for Hill Climbing and since putting wider tyres on I seem
to have made the bump steer worse.
Also has anyone experience of using a Quickrack on the car (2.5 turns lock
to lock), is this the same part as for a Triumph Herald/Spitfire.??

Thanks Barry Dickinson

[jcocking]

Hi Barry,
The dimensions are on the web site. There is also a comment on adding a
couple of shims to remove bump steer with larger/newer tires.

jeff
http://LotusElan.net

[types26/36]

Regarding the bump steer article on LotusElan.net, I rebuilt my Elan Coupe
around a new Lotus galvanized chassis and dutifully inserted the shims
specified on the rack mounting platforms - and had terrible bump steer. I
eventually measured the actual bump steer (raising and lowering front of
car without springs) and found I needed almost 0.25 inches of shim each
side to eliminate bump steer. (The steering is very stable and responsive,
this change was an immense improvement.) I have no idea if this ended up
being 2.19 inches from the lower wishbone pivot. Other Elans I have bump
steered all required quite a bit of shimming.

Since all the new chassis I have seen required more shims than specified, I
wonder if Lotus engineers designed in some bump steer? Or if the jig used
to determine shimming after chassis manufacture is simply inaccurate?

I also wonder why it is suggested that, if one eliminates bump steer, more
shims then need to be added if wider tires are used? The suspension and
steering geometry do not change when different wheels or tires are installed.

Randall
Seattle

[Richy-dick]

----- Original Message -----
From: A. Sta. Maria <[email protected]>

.
.



Andres

We all (I think) love our Elans dearly and want to know every intimate
detail about our lovers!
Many of them have secrets they are reluctant to give up and foibles which
give them more character.
Last night I went to a meeting of the North Yorkshire Lotus Owners Club and
there I felt I was with kindred spirits. Everybody was not just passionate
about thier own cars but about other's cars too.

Everyone

My +2 will need the steering rack adjustment doing sometime (months or years
I don't know) as a friend who was helping me earlier on threw away the shims
which came with the replacement chassis.
Where can I find the definite method of correctly adjusting the height?

Richard A Clifton
Wakefield

[paul_adamson]

------
From: "A. Sta. Maria" <[email protected]>

Randall,

Can I use different shim heights for the left and right rack mounts? Won't
this twist the rack housing tube? I was thinking of averaging the two
measurements (not a great difference actually).

Incidentally, wouldn't the lowered 26-R a-arms result in more shim height?

Many thanks and regards,

Andres
45/8439
---------
It appears normal to have different shimm heights (slightly). This is to correct for the small
twist in the chassi.


Brian
---------------------o0o------------------
Brian Scally - Philips Semiconductors Systems Lab. Southampton UK
tel : +44 2380 312654 fax : +44 2380 316303
mailto:[email protected] seri : bscally@ukpsshp1

[sprinterdave]

steer. It is not an easy job, it will take time and patience along with
some blood and tears.
Dave s

--
David Shiers

[abstamaria]

Randall,

When I restored my Elan the first and second times, I simply used the shim
height I found originally underneath the rack. When I replaced the frame
last year with a new "26-R type" frame I bought from Tony Thompson, I found
there was no recommended shim height stamped on the frame; Tony said I had
to do the bump-steer measurements myself.

This did not seem too difficult, and so, armed with advice from Tony and
instructions from Carroll Smith's several books, I proceeded with the job,
using a Longacre bump-steer tool. My measurements resulted in a lot of
shimming (about 1/4"), so much so that I had to replace the original rack
mount bolts (I use aluminum solid mounts). I was reluctant to call Tony or
even ask the Lotus List since I did not want to prove to everyone how
mechanically inept I was. I assumed that the shim heights would be in the
order of the heights I found on the original chassis, and was sure I was
doing something wrong in my measurements. So I kept redoing the bump-steer
measurements, with the same results. I was terribly frustrated.

How glad I was you wrote about your shim heights. Now I feel more confident
and can proceed with the restoration. This problem has actually held me
back. Many, many thanks.

And many thanks for the Elan List, Jeff Cocking. While I still subscribe to
the Lotus List (just in case I am lucky enough to pick up a Europa, Elise,
Eleven, or other Lotus in the future), the very narrow focus of the Elan
List has been really valuable to me. While the amount of correspondence
generated by those mysterious holes at the bak of the Elan glove box -- and
notes on rack shim heights -- might have been inappropriate in a general
list, they are certainly appreciated by and of great interest to Elan
enthusiasts (at least by this long-time Elan enthusiast).

Many thanks again.

Andres
Manila
Lotus 45/8439

Randall Fehr wrote:

[abstamaria]

Randall,

Can I use different shim heights for the left and right rack mounts? Won't
this twist the rack housing tube? I was thinking of averaging the two
measurements (not a great difference actually).

Incidentally, wouldn't the lowered 26-R a-arms result in more shim height?

Many thanks and regards,

Andres
45/8439

[types26/36]

Yes, each side will almost certainly require a different amount of
shimming. The rubber mounts on the stock clamps accomodate any 'twist'. But
even with your solid mounts, the very small deviation from perpendicular
should not cause any problem.

Keep in mind that since the clamps are not at the extremities of the rack
tube, raising one end will actually lower the other. Unless you are good at
geometry, you will probably have to do it mostly empirically - make an
initial measurement, add some shims, try again, correct shims, measure
again...

I am not familiar with lowered 26R a-arms, do you mean wishbones? If you
mean does lowering the car call for more shims, I think not. Ideally,
zeroing the bump steer means the wheels won't turn at all within suspension
travel (except by driver input), nut just within a specified range of
travel. As I recall, the Elans I have bump steered could be set very very
close to zero (within about 1/32 inch) all the way from full bump
(compression) through ride height and well into rebound. Seems to me one
can compromise quite a bit in rebound since that is the unloaded state -
perhaps that wheel is even off the tarmac if you use a stiff anti-roll bar.
The wheel could even be flapping in the breeze and not affect handling!

Randall


At 22:35 7/28/99 -0000, Andres wrote:

[types26/36]

One or more of the Carrol Smith books '...to Win' describes a method using
proprietary equipment including a dial indicator. Intended for racers.

The book 'How to Make Your Car Handle' by Fred Puhn published by HP Books
perhaps 20 years ago, sold through Motorbooks International, describes a
basically similar method but using simple home-made equipment. With care,
one can get entirely satisfactory measurements with this set-up, certainly
good enough for a road car with lots of rubber in the suspension.

Randall

[paul_adamson]

Is there any chance that someone could summarise this and post it to Jeff.

I think that it would make a vey interesting addition to the webb site.


Brian
----
From: Randall Fehr <[email protected]>

One or more of the Carrol Smith books '...to Win' describes a method using
proprietary equipment including a dial indicator. Intended for racers.

The book 'How to Make Your Car Handle' by Fred Puhn published by HP Books
perhaps 20 years ago, sold through Motorbooks International, describes a
basically similar method but using simple home-made equipment. With care,
one can get entirely satisfactory measurements with this set-up, certainly
good enough for a road car with lots of rubber in the suspension.

Randall
---------------------o0o------------------
Brian Scally - Philips Semiconductors Systems Lab. Southampton UK
tel : +44 2380 312654 fax : +44 2380 316303
mailto:[email protected] seri : bscally@ukpsshp1

[abstamaria]

Richard,

By now you should have read Randall Fehr's advice on which books to get. I
relied on Carroll Smith's Prepare to Win, which Randall noted. Smith
describes the process more clearly than I can, so I would suggest that you
consider the books Randall suggested.

Sorry for the delay in responding - I am in a different time zone!

Regards, and you are lucky to be with so many Elan enthusiasts. The last
time Lotus enthusiast I was with was from Singapore.

Andres
Manila
45/8439

[rsfehr]

Not me - it would take too long, and amount to a copyright infraction!

Randall


At 10:48 7/29/99 +0200, Brian wrote:

[abstamaria]

Barry,

Where does one get a Quickrack for the Elan?

Regards,

Andres
45/8439

[abstamaria]

Randall,

You wrote:


I meant the 26-R type front A-arms for the Elan (with rod ends). These are
curved (upward for the lower arms and downward for the upper), resulting in
a lower ride height (and they say better geometry).

Regards, and thanks for the bump-steer advice.

Andres
45/8439