karim.marouf@cancom.com wrote:
>
> When you're lugging your motor (i.e. flooring it in too high a gear on a
> hill), how exactly are you damaging the motor (disregarding pre-ignition)?
> Are the main bearings being damaged because not enough oil is circulating,
> or are the cyclinder walls being scored for the same reason?
When tasking a motor on the small end of the torque curve, you are
forcing the motor to generate a whole lot of extra heat. The radiator
does its part but you are still super heating the oil, tops of the
piston, head, and plumbing. When everything is tip-top the motor can
survive this for quite awhile. When not, doom is just around the corner.
You don't automatically ruin bearings or score cylinder walls as long as
the oil is within its operating range. But once tolerances are exceeded,
wear is greatly accelerated. It's a pity there isn't and oil temp gauge
in every car.
> Another question: if you're running your motor on the freeway at 4500 rpm,
> are you causing a lot more wear than if you had an overdrive and were only
> using 2500 rpm?
You'll get some argument here. Running at the torque peak is the best
way to make an engine live. But, like every other moving part, the more
it spins the faster it arrives at its demise. Every motor only has so
many revolutions in it. But there are extinuating circumstances (check
with the 'A' owners on spelling) as mentioned in your first query.
--
Bob Allen, Kansas City, '69CGT, '75TR6, '61Elva(?)
"The biggest thing that happened to the six-cylinder engine in 20 years
was the seven main-bearing crank" -- John Z. DeLorean, Car Life, 1966
|