>It seems self-evident to me that (all other things being equal) if the
>engine doesn't have to turn over as many times per mile while the OD is
>engaged, it's useful life will be extended. We generally compare engine
>longevities in terms of miles driven between overhauls. The fewer
>revolutions the engine turns per mile driven should result in more miles
>driven between overhauls. Seems like elementary logic to me.
>
I have heard it said from my Chevy mechanic and I believe, others on
this list, that only about 20% of engine wear occurs at highway speeds - the
other 80% occurs at start-up. If this is true, and you were really
interested in reducing engine wear, your money might be better spent buying
a kit that pumps oil through the engine before start-up.
Of course, I don't have any data to support this assertment. There's no
way of knowing if 'X' amount of wear takes place at 3500 rpm (with OD
engaged) and 'X' + 'Y' amount of wear takes place at 4500 rpm (without OD).
I have owned an OD car and I had an OD transmission. I sold it, because
to me, I could use that money to restore the car rather than add something
to it that was only moderately useful to the car. To be frank, it's nice to
have a vehicle that has torque at highway speeds, since most 4-cylinder cars
that I drive lag along at highway speeds...Of course, they have 5 gears too!
Michael S. Lishego
http://www.geocities.com/MotorCity/Speedway/3706/
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