"navaidstech" > wrote in message
...
snip
> IMHO, This is excellent service life, and your maintenance program and
> schedule is obviously working well for your driving conditions and your
> driving style. I suspect you do mostly highway with few short trips, have
> a
> std tranny and keep your revs low. Are you still on your original clutch?
>
> Good luck,- Hide quoted text -
>
> - Show quoted text -

Thanks!

I did exactly that ever since I got the car. Kept the revs at between
2000 and 2500 on the highway, which put me at around 60-65 mph. VERY
RARELY has the engine gone past 2500 RPM.
I did a lot of highway driving up until about 3 years ago when I got
transferred to a work location much closer to my house. I used to
drive about 40 miles each way for about 15 years, 80% of which was
highway miles. The engine went through all sorts of weather conditions
that you can encounter up here in the Toronto area - very hot summers
and cold winters - I think the money I invested in Synthetic oil sure
have paid off.
I currently drive about 15 miles each way, and it's a 50-50 mix
highway/city streets. I have a feeling that this increased stress will
eventually kill the clutch, which has never been replaced since I
bought the car.

I am impressed with both your service life and your disciplined driving
style, it verifies much of what I have suggested previously. I will admit
to reving slightly higher than you on occasion (usually under 3000 but
occasionally higher) but in my defense also operate on much steeper mountain
grades than you do, and often haul considerable weight. I have always
thought that the S series SOHC engines greatest unappreciated strength was
the flat low RPM torque curve that permits most operation at low engine
speed which considerably reduces engine wear and fuel consumption.

I am unaware if you are a pilot in addition to your navaidtech work. Most
people are unaware that aircraft engines operate in a similar RPM range and
are designed with a flat torque curve. They use larger displacement engines
operating at relatively low (1500-2700 rpm) to maximize service life and
reliability. Smaller higher reving (Rotax and others) engines seldom have
as long a TBO (time between overhaul) as the lower operating speed
Continentals and Lycomings. The SOHC S series engine torque peak is at 2400
rpm. Torque peak is usually the point of maximum volumetric efficiency and
of min fuel consumption (per HP produced)

The SOHC S series 5sp transmission has quite a low gear ratio in 1st gear
which combined with the engines good low speed torque allows one to get
rolling at low engine speed and without excessive clutch slippage. (Heavy
vehicle drivers are trained to start out in the gear which will allow
start-up without adding throttle.) I find that the shift to 2nd gear can be
made in a very short distance and at quite low engine speed. I am a big
believer in 'progressive shifting' where the shift point rpms are
progressively raised as we work our way up the trany, but with the shifts
been made as soon as possible. This is sometimes called 'short shifting'.
I think this is the major factor in long clutch life but you should claim
much of the credit for having and performing good and disciplined driving
skills, I bet you keep your foot away from the clutch pedal unless you are
using it.

I hesitate to suggest that you vary a maintenance schedule which is
obviously working well, but most engines experience increased oil
contamination rates as they age and this will also be increased by short
trips, particularly in the winter months as the engine oil will spend less
time at full operating temperature which will reduce moisture boil off and
crankcase cleaning through the PCV valve and cause increased acid formation
in the oil. Due to your decreased trip lengths, I would suggest that you
consider reducing your change intervals particularly during the cold months.

I hope you can make it to 1,000,000 km. consider this a challenge.

Good luck, YMMV