First off I will apologize to any and all for any patronizing
on my part. I tend to be overzealous in my dislike of trophy cars,
particularly sports cars turned into trophies. I probably see
phantom "trailer queens" and so forth. Even when opinions are sharp,
it is never my intention to attack or defame.
At 06:39 PM 5/6/98 -0600, Charles & Peggy Robinson wrote:
>Keith Wheeler wrote:
>>
>
> SNIP
>
>> This thread is really a question of how to make an MGB engine last,
>>
>
> Not really, the guy asked about 5-spd versus OD for his money. Either
>way, he wanted the highway revs down.
>
>
...because the gentleman was concerned with engine wear. I still stand
by the theory that the money is better spent on balancing the engine
and other longevity tricks. After stating this opinion, Charley replied:
> Some of us want the engine to last _many_ more than a couple of
>years. That's why we go with the original factory driving handbook that
>advises us to keep the revs below 4,000 for best economy and longevity.
>
> How anybody can't see that running the car in OD results in fewer
>engine revolutions per mile, and thus less wear, is beyond me.
And as many have said, the overdrive, as a method of reducing engine
wear, is, to quote John Twist, very respected MG wrench turner, a
placebo. Yes, if you drive a lot of highway miles you'll save fuel,
but saving the engine, nope.
So I stand by my opinion that in face of this information, anyone who
wants a long lasting B series powerplant and then spends money and
effort on an overdrive is probably more conerned with the gee-whiz
factor of having a rare bit on their car.
As far as MG was concerned:
from a '72 Driver's Handbook:
(which incidently only says "...that for sustained speeds at or near
the maximum..." and not "...above 90..." as I had remembered-was that
in an earlier edition of the handbook?)
"For normal roadwork, and to obtain the most satisfactory service from
your engine, select the appropriate gear to maintain engine speeds of
between 2,000 and 4,500 r.p.m.
When maximum acceleration is required upward gear selections should
be made when the needle reaches the yellow sector (5,500-6,000 r.p.m.).
Prolonged or excessive use of the highest engine speeds will tend to
shorten the life of the engine. Allowing the engine to pull hard at
low engine speeds must be avoided as this also has a detrimental effect
on the engine."
So, Abingdon didn't seem to mind the 4500 or so necessary to run
a non overdrive 'B at 70 MPH. This from the guys who had to deal
with warranties and the like.
Ah yes, I've found it. From the "MGB Tourer and GT Driver's Handbook"
with a copyright "The British Motor Corporation, 1969":
Under "Tyres, Standard Tyres, Pressures":
"Sustained speeds in excess of 90 m.p.h.
Front 27 lb./sq. in..."
While I do drive my 'B hard, my "couple of years" comment regarding
clutches wasn't spot on: in the 12 years I've had my 'B it's had
three clutches in it. The first, shortly after I got the car.
(Typical good price on a 'B: clutch is slipping, and owner doens't
want to deal with the hassle/expense). The second was during my
first (and only full) rebuild, and the third during a freshen up
not too long ago because I dropped the clutch disc and damaged it.
I understand what it's like to be with a proper garage. I'm 1600
miles from the Team's garage, dealing with the hell of urban
apartment dwelling in the insanity of Southern California...
...however, if I can get 6 or 7 years from a 'B engine, routinely
(as in every few days) running sustained 70 MPH stints, along with
the harsh world of autocross driving, I don't see why an enthusiast
should be concerned with running a bit over 4000 RPM every now and
then.
Again, I apologize for any patronizing tone of my postings. My primary
interest is seeing MGs on the road, with good lives. Of course, unlike
many, my secondary interest is seeing them driven as they were intended
to be driven.
-Keith Wheeler
Team Sanctuary http://www.teamsanctuary.com/
|