[200q20v] Re: [s-cars] Delrin/ urethane bushing alternative

[perry]

Trevor,
  Warning: Delrin when burned emits extremley hazardous
and life threatening fumes. I used to work at a plastics plant
just out of high school. One day we had burning Delrin on the
production floor, all personnel had to be evacuated. It was
so bad that it made your throat swell completely shut with the
first breath. Felt like a gorilla had grabbed me by the throat..
 In other words don't burn it! Oh wow!!
  TTFN, Perry_____________

Trevor Frank wrote:

> Unmodified Teflon would be much worse than Delrin.  Teflon has a tendency to
> creep and therefore is not suitable for bushing applications that would take
> much if any real load.  I have manufactured bushing for different race cars
> over the years and in one case made replacements for Teflon bushings that
> had deformed in a very short time.  Delrin is inexpensive and tough, it is
> easy to machine and is well suited for a bearing material, I have seen it
> used successfully on everything from a Mini Cooper to an IMSA GTP/ Group C
> car.  Modified nylon bushings in my opinion are one step better, they are
> harder but when modified with Moly or Kevlar or ??, have a lower coefficient
> of friction than Delrin, i.e. Nylatron GS.  Peek is very expensive and not
> well suited for our application.  It is brittle and because of this it tends
> to chip and scale under high loads.  Peeks real strength is in its chemical
> inertness.  If you want to spend this kind of money and match the
> coefficient of thermal expansion better than nylon or Delrin or Peek then go
> to a bearing grade of Torlon $$$$ or even better yet use Vespel $$$$$.
> Coefficient of friction is a reference to but not totally corollary to the
> abrasiveness of a material.  Plastics can and will wear on the steel and or
> aluminum that makes up the suspension components.  This could over some time
> loosen the suspension of any race car.  It is important to look at what the
> "k" factor is or Wear Resistance.   I have found that to get a good fit with
> these harder material, anything other than urethane or rubber, it is
> necessary to custom fabricate each bushing to match each component.  This is
> due to the fact that these components where never machined to much precision
> or accuracy.  This is probably overkill for the street car and I feel that
> only a few race car drivers would notice the difference, but for those who
> must have it I have done it.  Another trick is to use as little bushing
> material as possible, instead fabricate an aluminum or steel sheath that
> covers the outside or inside of the bushing, then press fit the bushing
> material on to it, then press fit the assembly onto the suspension.  The
> disadvantage is that you may never get it out again.  In this interest it is
> always best to use a dissimilar material.
>
> To be an informed consumer, pick up a DSM Engineering Plastic Products
> Design and Fabrication Reference Guide.  They have many if not all of the
> materials worth considering for this application.
>
> -----Original Message-----
> From: Kaklikian, Gary [mailto:gary.kaklikian at compaq.com]
> Sent: Tuesday, October 02, 2001 7:46 PM
> To: Audi 20V (E-mail); s-car-list at egroups.com (E-mail); 200q20v (E-mail);
> Brandon Hull
> Subject: RE: [s-cars] Delrin/ urethane bushing alternative
>
> I spoke with Shine Racing earlier this year about control arm bushings
> for my 4000tq.  They said they could fit their Teflon bearings to this
> application.  At the time, I had poor luck with urethane bushings and
> switched to delrin.  Well, after less than 10 track days, the delrin
> bushings have begun to creak and apparently there is some deflection
> occuring since handling does not seem quite as precise as before. Yet,
> all of the control arm bolts are tight. So, I plan to contact Shine
> Racing again to see what they can do and, if necessary, send them a new
> set of control arms to fit their bearings to.
> I'll keep you posted on how this works out, but since I've also got
> engine problems with the car now, it will be a while.
>
> HTH
> Gary Kaklikian
> '86 4ktq
> '92 S4
>
> > ----------
> > From:         Brandon Hull[SMTP:brandon at cardinalventures.com]
> > Sent:         Tuesday, October 02, 2001 7:31 AM
> > To:   Audi 20V (E-mail); s-car-list at egroups.com (E-mail); 200q20v
> > (E-mail)
> > Subject:      [s-cars] Delrin/ urethane bushing alternative
> >
> > I happened upon this fascinating site today:  Shine Racing, a VW tuner
> > in MA
> > makes a needle bearing bushing insert for suspension control arms.
> > The
> > advantage would be near zero friction in the suspension movement, with
> > zero
> > play.  (maybe a bad thing as has been discussed, if we assume mass
> > production engineering factors in some slop here to accomodate
> > production
> > variances)
> >
> > In any event, I'm curious to know if anyone has pursued this for Audi
> > applications.
> >  http://www.srsvw.com/basic.htm
> >
> > A step by step Porsche installation:
> > http://www.all914.com/projects/ScottY/Part1/index.htm
> >
> > Brandon Hull
> > eS2
> > 911SC
> >
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> >
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