[Shop-talk] Frozen sway-bar slider

Tue Sep 17 09:49:39 MDT 2024

On Tue, Sep 17, 2024 at 8:12 AM old dirtbeard <dirtbeard at gmail.com> wrote:

> Hi Phil,
>
> Your Cat 1700 sounds like a wonderful car. I think they were about 135HP
> if I recollect correctly.
>

You are correct, sir!

Had it on the scales last Thursday.  1340 pounds.  My previous Caterham was
1275.  I could not figure out why, but I think it is largely due to the
rollbar.  This one has a REAL rollbar, and I think the other one was a joke.

Do you think the LSD helps traction significantly?
>

Dunno.  Never drove this car without it.

>
> I always thought that with under 150 BHP an LSD probably was not much of
> an advantage, just additional maintenance, but it sounds like you think it
> is beneficial.
>
> I just rebuilt the rear axle and pumpkin on my '56 Lotus Eleven and
> decided against an LSD at the time and you have me wondering whether I
> missed an opportunity. I have a Climax FWE at only 110 BHP and the car only
> weighs 950 lbs, so it is significantly less powerful and probably lighter
> than your Seven. Just curious if you had yours with an open diff before
> going LSD.
>

There was an open diff on my first Caterham and I did get wheelspin on
corner exits. Then I went overboard and put in 4.11 gears and a Quaiff
"TorSen".  That worked out fine.

Now that I have stiffened the rear swaybar, the LSD is more-important than
before, since by-definition a sway bar works by trying to pick up the
inside wheel.  This adds roll stiffness to the entire car and makes the
front stick better.  I had an adjustable serious rear sway bar on my MG
Midget.  I was always under there tinkering with it, walking a tightrope
between understeer and wheelspin since that car had an open diff.

I suspect that on a racetrack or canyon-carving, this Cat would not get
much added value with LSD, but in autocross corners, I am pretty sure the
LSD helps.  I always wished I had the TorSen in my Elise.  I had one in my
Miata, and I am sure that it helped.

I have no idea why the original owner specified LSD, but I am glad he did.
On the other hand, I cursed whomever put a plate-type LSD in my Europa, as
it made the car push terribly in autocrosses where the traction was not
first-rate.  I put in a bottle of Slick-50 Man Tran and that reduced the
breakaway torque from 90 to 20, which helped a lot.  Since there is more
weight on the front wheels of the Cat than on a Europa, I don't expect that
I will be wishing I had a TorSen.

>
>
> I'm not racing it currently, just doing the canyons here in SoCal with
> "exuberance."
> [image: PXL_20240915_220640034.jpg][image: PXL_20240915_215013737.jpg]
>
> On Mon, Sep 16, 2024 at 9:30 PM Philip Ethier <pethier7 at gmail.com> wrote:
>
>>
>>
>> On Mon, Sep 16, 2024 at 6:36 PM Thomas Coradeschi <tjcora at icloud.com>
>> wrote:
>>
>>> I think heat is gunna be your friend.
>>>
>>
>> I didn't have to resort to the blue flame.  The slider block finally came
>> loose with liberal application of Kroil and 1100-degree-F air from a heat
>> gun followed by a twist with a pair of vise-grips.  Ran a half-inch reamer
>> through the block. Polished all the corrosion off the sway bar with a
>> sandpaper strip and eery cloth.  Block is 20mm long.  Used one block to put
>> saw marks 20mm apart on each bar arm on both the inside and outside to
>> serve as guides to settings.  I set the bar two notches up (40mm plus saw
>> kerfs). Cat is much-more neutral now.  Front tires are sharing with each
>> other better with car rolling less.  Plate-style LSD is preventing
>> wheelspin.  This has transformed the handling, There is much more overall
>> grip.  I can provoke both understeer and oversteer now.  May try one more
>> notch at next weekend's autocrosses.  I did have to put a little more bend
>> in the endlinks to allow one more notch.   They are factory-bent to clear
>> the DeDion tube.
>>
>> Took out the lateral drift on the brackets with slit PEX pieces held in
>> place with hose clamps. Clicky noise is gone.
>> Phil Ethier
>> 1991 Caterham 1700 Super Sprint
>>
>>
>>
>>>
>>> On Sep 16, 2024, at 2:02 PM, Philip Ethier <pethier7 at gmail.com> wrote:
>>>
>>>
>>> Saturday I ran a small-lot autocross at a dragstrip near Rock Falls
>>> Wisconsin.  My Caterham was pushing a bit and I had trouble staying in the
>>> power band in second gear.
>>>
>>> Also, there is a light clicky sound when I drive over bumps on the
>>> street.
>>>
>>> The click is probably the rear sway-bar moving sideways and hitting the
>>> hose clamps that locate it in its aluminum-block brackets.  First shot at
>>> quieting it is to put in a couple of cable ties between the clamps and the
>>> blocks.  If that does not do it I will slit some PEX.
>>>
>>> Next, adjust the rear bar stiffer.  Problem:  I have removed all the
>>> fasteners and the blocks will not move.  The Heim joints pulled out OK.  I
>>> swung the bar down.  It moves very easily.  I shot the blocks with Kroil,
>>> smacked them with a wrench and stopped for lunch. At least if I need to use
>>> heat, the part is far from anything to damage.
>>>
>>> https://www.flickr.com/photos/pethier/54000198064
>>>
>>>
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