<<An overdrive is great if you want a more civilized MGB. I don't. I want
something that screams and whines on the highway. I'm sick of cars that are
less noisy, cars that are nothing but isolated little boxes on the road. >>
Well, this sort of statement surprises me unless you are pretty young, or
perhaps own a post-74 B which is more sound than fury in any case. May I
assume that you drive around town in first gear?
If you want to tear down the highway with your engine screaming, ( a rather
puerile activity in my book), chacun a son gout, but don't try to argue the
point that high rpm usage won't wear an engine out sooner than middle rpm
running.
The actual time that an engine will last is a curve, with accelerated wear
the higher you run it. Ask any engineer (which I am not) or any engine builder
that builds racing engines (which I am).
A propos of engine wear, some of you might be interested to know that in
development of the Jensen Interceptor, the factory ran an engine on a brake at
5000 rpm to see how long it would last. It went 30 hours before a bearing went
and blew the engine in a big way. That was close to the stock redline for the
big block Chrysler. If it had been run at 3000, it would have lasted many many
times as long.
Another example - the TR engine, a long stroke 4 cylinder, will last
indefinitely at up to 6000 rpm, a half hour or so at 6500 if properly
prepared, and minutes at 7000 rpm. Mind you, if you are in the final lap of a
race, it is sometimes worth it to run it up there if doing so means that you
win. But then you have to tear it down completely after the race.
An OD unit lets you maintain cruising speed at an rpm closer to the torque
peak of the engine, at lower fuel consumption than would be experienced at
higher rpm.
Anyone that is too fumble thumbed to flick a switch when they want to pass
shouldn't be trusted in a car of any type, IMHO.
Bill S.
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