As the Astra has a timing belt (as did the L300 V6 and the Honda-powered V6
VUE) and all other Saturs have a timing chain, I wanted to stsrt a thread on
the pros and cons of both. Both have thier vulnerabilities and good points.
Saturn belts are good for 100K mi, which is more than many out there.

Googling for this info revealed lots of useful info. Gave me a a good heads
up on both to ponder.

http://newsgroups.derkeiler.com/Archive/Alt/alt.autos.toyota/2008-02/msg02133.html

http://www.google.com/search?q=advantages+of+timing+belts+over+timing+ch ains&rls=com.microsoft:en-us&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1

--
marx404
<all gmail posts blocked>
_________________

My 2001 LW300 V6 had almost 100K on it when I replaced the timing belt. The
belt had practically no observable wear at that point and was otherwise in
good shape. I bought the car with 40K on it and will assume that nothing
happened in the previous life that required a new belt.

would have replaced the belt myself except for the large amount of special
tools to hold the cams locked into position and align everything. there are
two tensioners and the relation between the two sets a fine timing position.
Way too tricky and catastrophic to the engine if a mistake was to be made.
I've done chains and belts on other less complicated engines. On Chain
drives, you have to remove more of the front of the engine to get the front
cover off.

Oppie

Ever since most of the ISPs killed alt groups, I've been using teranews for
most of my ng access. Lately, I haven't been able to post and article
retention is getting pretty bad. Just realized that I could still access
this group through the verizon ng server. I'm going to have to find another
independent usenet provider and tell teranews to take a hike.

"marx404" <404 (AT) 404 (DOT) com> wrote

Not that timing chains are perfect either. Back in my ford years, I rebuilt
two engines that were damaged by a failed timing chain. The chain itself was
still in reasonable shape as was the crankshaft sprocket but the camshaft
sprocket which had Nylon (iirc) molded teeth was worn and allowed the chain
to skip.

That being said, it is important to add that most 'modern' engines with
timing chains now include some sort of chain tensioner to not only tension
it but to damp it from flopping about at high speeds. All the tensioners
I've seen lately are a combination of spring and hydraulic assist (operated
from engine oil pressure).
Oppie

marx404 wrote:
pump. I believe these are driven by the timing chain, and I don't think
I like that idea. The cost of the water pump would probably far exceed
replacement of timing belts and water pumps for the life of most other
engines.

--
Gyz

Everyone thinks they know how to drive.
Everyone thinks they are good drivers.

A/C Compressor is usually driven by its own belt. Water pump can be driven
by either a serpentine belt or in some designs, by the timing belt. I've
never seen these both driven by the timing chain in any vehicles I've worked
on.

Bob

"Gyzmologist" <ru-nuts (AT) home (DOT) com> wrote