Art,
Perhaps the answer to our questions about breaking-in (of the engine,
not of houses and banks) could be answered by our determining what it is
that happens during the "break-in" period.
I remember snippets about camshafts needing to run in at varying
speeds, though never could understand why something rotating at 1/2
engine speed could be affected by changes in rpm. I recall that when
chromed rings were introduced, one was supposed to drive faster and
harder so that the rings would not take a "set", somethign that was
supposed to happen if you ran them in slowly as done before the days of
chrome rings.
Somewhere I read that if there are high spots on rubbing surfaces, a
gentle running-in gave time for the high spots to wear away without
overheating the rest of the bearing/fitting/whatever. How tight; how
hot, I don't know.
Tom McCahill, said to have been knowlegeable about engines during the
50s and 60s, wrote that his breakin practice was to go by the book for
the specified mileage, then change oil and filter, and then to flog the
engine mercilessly. He would break it within the warranty period, he
said, or train it to be fast, as in "Break it in fast and it will run
fast."
It's remarkable that we all believe to some extent in "running in" yet
most of us, myself included, know not why or for how long.
Wonder what large engines, truck and bus engines, receive for break-in.
How about aircraft engines?
Bob
On Mon, 6 Oct 1997 19:46:58 -0400 (EDT) Art Pfenninger
<ch155@FreeNet.Buffalo.EDU> writes:
> The only problem is that if you pick up an engine rebuilding
>book
>for say a chevy it will also tell you to break it in. I was at the
>library
>today trying to answer my own question and one book ended the
>paragraph on
>break in with "trust me the engine will last a lot longer". Ok where
>is
>the data. Everyone seems to agree but only because it seems like the
>right
>thing to do. Ask around at work on how many break their new cars in. I
>think the previous writer may have a point when he said it is done in
>the
>factory, but how?
>...Art
>
>On Mon, 6 Oct 1997, ROBERT G. HOWARD wrote:
>
>> Art,
>> Could it be that the new car manufacturers recognise that today's
>> production tolerances are so small that break-in is no longer
>required?
>> After all, they recommend 5-30 oil, pretty thin stuff at the 5 end
>of the
>> viscosity spectrum.
>> Our MGs are loose by modern standards, one would think. How do the
>specs
>> for piston and cylinder size for rebuilds compare with the specs for
>new,
>> modern engines?
>> Once upon a time (TD & TF time) the workshop manual spoke of the
>> different sized (that's right--different sizes!) of pistons that
>could be
>> used in a given engine because of the different bore sizes.
>Balance?
>> What's that word?
>> Just my assumptions---no basis in engineering knowledge at all.
>> Bob
>> English major, long time ago.
>> Took a math course, once.
>>
>> On Mon, 6 Oct 1997 10:32:22 -0400 (EDT) Art Pfenninger
>> <ch155@FreeNet.Buffalo.EDU> writes:
>> > Question of the day...After an engine rebuild why do we
>> >practice
>> >the ancient ritual of the dreaded BREAK IN PEROID? It used to be
>that
>> >when
>> >you bought a new car and drove it off the showroom floor you had to
>
>> >break
>> >it in. Today you pick up the car and off you go 60 miles an hour.
>Do
>> >any
>> >of the manufactures still require a break in peroid?
>> > I know what the books say about this (they actually don't
>say
>> >much
>> >if you really read them) some even give a schedule to follow after
>a
>> >rebuild. I suspect however that this information is being carried
>over
>> >from when this was required by the industry. Unless the companies
>that
>> >produce the replacement parts have a stock of old metal that they
>melt
>> >down
>> >I can't see any difference between a rebuilt engine and a new one.
>> >Parts
>> >is parts. Now if the new car companies still require a break in
>peroid
>> >then thats another story.
>> >...Art
>> >
>> >
>>
>
>
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