I just returned from the UK and Ireland where I sat through 1500
miles of being driven by my brother-in-law who lives near Milton
Keanes. This otherwise good driver has a Vauxhall (1990 reg.) with
5 speed stick.
He continually starts this car moving and after it is in the least
bit of forward motion, he jams it into second gear and the revs drop
to 800 or so...then he acelerates up through the gearbox to desired
road speed.
I am worn out telling him about lugging engines...the harm.. the end
results etc. He may be too old to unlearn the poor habits he has
picked up??????
I even gave him some demo rides in which I ran up to a gentle 1800-
2200 in first and second, just to show him how it feels and sounds.
No avail....he was back to old habits at once.
When I lectured my engineering students I mentioned that "baring
excessive high sustained rpm, more harm is done to an engine from
hard work at too low an rpm than was caused by being driven briskly
with no low rpm lugging."
In the era prior to say 1955, most engine designers had certain
perameters within which they felt obligated to stay in order to
assure engines not breaking.
The most common one was piston speed ! It was felt that 2500 fpm was
as high as an engine should be run to avoid failures.
Then came the 1949 Jaguar XK120 engine with long stroke and quite
high rpm range. It also stayed together when run at piston speeds in
excess of 3000 fpm.
Well, bearing makers as well as piston designers were forced to
advance the state of their arts and Vandervell (UK) came with lead
indium bearings which were amazingly tough.
Short stroke engines which reved higher also started to show up and
today we have very short strokes yet we have extreme piston speeds....
.and vastly higher specific outputs.
Dick T.
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