quattro Digest, Vol 8, Issue 68 - RE: [s-cars] Serpantine belt breaking the timimg belt

[Larry C Leung]

Eric,

As an ex-engineer, I understand Eric's questions.  My understanding
of the design parameters are:

Size - apparently a timing chain cover and drive of sufficient strength
to run, particularly multivalve engines, takes up more axial space than
a timing belt. 

Noise - Chains and gears BOTH produce alot more noise than belts.

Cost - Yup, belts and pulleys do cost less than gears or chains.

Longevity - Apparenly, belt technology, even in the early-mid eighties 
has a comparable service life to chains (don't know the comparo to 
gears). In reality, it appears to be half as long. But don't forget,
roller
chains also wear out, so they must be eventually replaced, as well
as their tensioner. Just ask my old Saab 99 on that one. 

HTH!

LL - NY


> Date: Mon, 21 Jun 2004 09:37:04 -0400
> From: Eric_R_Kissell at whirlpool.com
> Subject: RE: [s-cars] Serpantine belt breaking the timimg belt
> To: "Calvin & Diana Craig" <calvinlc at earthlink.net>
> Cc: Dave Forgie <forgied at direct.ca>, quattro at audifans.com,
>         s-car-list at audifans.com
> Message-ID:
>        
<OF04934D79.42FC47B0-ON85256EBA.0049F86F-85256EBA.004ACE14 at whirlpool.com>
>         
> Content-Type: text/plain; charset=us-ascii
> 
> 
> "Calvin & Diana Craig" <calvinlc at earthlink.net> wrote:
> 
> >Of course all this would be solved if the damn manufacturer wasn't 
> too
> cheap
> >to use a chain or timing gears in the first place.
> 
> Which opens the door for a debate as to why Audi (& Volkswagen) 
> chose a
> timing belt rather than a chain or gears.
> 
> What are the advantages of a timing belt over other options?
> 
> What are the disadvantages of a timing belt over other options?
> 
> In my job that we have to balance all of the design criteria and 
> cost is
> only one consideration. Has Audi chosen the timing belt alternative 
> for any
> reason other than cost? Is the cost actually less than other 
> alternatives?
> 
> Eric