Regarding wear on the engine, since so many people have mentioned it...
One would think so, but last fall I asked about increased wear on the
engine, or the dangers of running at 4000 to 5000 rpms continuously, as it
was apparently that's what I'd have to do in highway traffic.
The consensus from people who rebuilt engines for a living was that there
was no appreciable difference. If anything, sometimes the engines were
better since they'd been "cleaned out".
Wear and tear on the driver were something else, but the engine itself did
not suffer unduly.
However, effect on MPG did not come up at that time, which is why I brought
that up now. But lest we reopen the other thread, the learned consensus
was that the engine was okay - not what I expected for an answer, but then
again, I don't rebuild engines for a living.
- Tab
At 10:47 PM 7/17/00 -0600, Phil Bates wrote:
>I don't know about Tab and Stewart, but I have driven my MGB with a 4
>synchro non-overdrive, and with a 3 synchro overdrive, and without using the
>overdrive. I drive 30 miles each way every day to work and back. I also
>measure every tank of gas I use. I agree that my car isn't in perfect tune,
>because I get about 23 mpg, and I should get closer to 30, but reguardless,
>I get about the same using OD as I do not using OD. The biggest difference
>is the comfort level (and I assume wear on the engine, but I haven't worn it
>out yet). It is so much quieter, and more comfortable with OD, the even if
>it got worse gas mileage (which it almost never should) I would use it
>anyhow.
>
>Phil Bates
>
>Charley & Peggy Robinson wrote:
>
> > Hi Tab,
> >
> > Forget the anti-OD bunch. They just feel that way. It's like having
> > a toothache.
> >
> > ODs save gas and wear. How much is according to how you drive the car
> > and the terrain you drive it over. It also depends on how efficient the
> > car is to start with. If the car is a gas hog because the engine is not
> > in tune, the OD may not help much.
> >
> > Look, I have a '69 B roadster. When I'm running on the freeway at 70
> > mph and engage the OD, I have to back out of the throttle to maintain
> > the 70 mph. Now, that has to mean something.
> >
> > I haven't had a chance to clock this car but in the '70 B w/OD that I
> > had before, the OD was good for ~5 mpg on the flats, cruising at 70
> > mph. I can vouch for these figures because I built the engine that was
> > in the car, took it on a trip to CO, and put the OD in it later. After
> > that we drove the car from TX up through OR and home. I was paying
> > attention to gas mileage during both of those trips.
> >
> > There is plenty of anecdotal evidence, such as mine, to extoll the
> > virtues of OD. There is also plenty of scientific data available to
> > prove that ODs work.
> >
> > Ida no about the vibration, didn't read about that. Replacing the
> > tranny to cure a vibratiuon seems chancy to me.
> >
> > CR
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