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VTMechEng

VTMechEng

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To get two metal blocks to stick together they would have to be machined with such perfection it would cost huge amounts. When an engine breaks in it does not have the capability to become that smooth. In engineering classes we never even discussed friction increasing as a result of smoother surfaces so I am guessing (and really don't know) the surfaces would have to be so smooth that it never really happens. This is how friction works to engineers:
Assume a block sitting on a table.
Static friction - Force exerted by the table on the block before the block begins to move.
Dynamic friction - Force exerted by the table on the block after the block begins to move.
If you try to push the block from a start it will always take more force to get it moving then it will to keep it moving. This is because the "coefficient of friction" is less for dynamic friction then for static friction. u(s) > u(d)
The equation for Friction is: F = u * N
F = force of friction acting on the block
u = coefficient of friction (whether static or dynamic)
N = the force applied by the block directy onto the table

At no time did we ever worry about things being too smooth. I do know that too much pressure will cause an oil film to collapse though.
 
SIRCHOPALOT

SIRCHOPALOT

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glens said:
That was a nice overview.

I had an instructor in a machine design class once who'd stated that if two surfaces could be made perfectly flat then stuck together, you'd not be able to get them apart again; that no fasteners would be necessary.

I was amazed at the article I referred to earlier where these professional mechanics were wiping down the cylinders with acetone before final assembly.  You'd think they and the rings would gall all to hell, but apparently not; at least it wasn't detrimental to the race-bike engines, which don't really need great longevity.  I'm certain the various journals were indeed pre-lubed though.

if you don't think they need great longevity, I'd say one GP bike race at daytona is equal to 20 years or better on your chainsaw!
 
TonyM

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Engineers have a lot more to concern themselves with than just making an engine have a lot of power. They have to design an engine in a way that it can be mass produced, design tooling, fixtures, machines, and procure machine tools to do the work. They have to obtain materials and establish specifications and tolerances and verify that all the processes are capable of building consistant parts. Then they have to create procedures and processes that can be used to teach someone else to make the parts, usually workers who themselves are not highly skilled in engine design and manufacture. Then they have to debug manufacturing clitches and support production. All the while this has to be done keeping in mind the cost has to be competitive in the market, and things always have to be done quickly. That's a little different environment from one where the objective is to win races. A lot more compromises and trade-offs have to be made. It is pretty amazing that we can buy a chainsaw with the performace it has for only $600, or any other product for that matter.
 
SIRCHOPALOT

SIRCHOPALOT

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TonyM said:
Engineers have a lot more to concern themselves with than just making an engine have a lot of power. They have to design an engine in a way that it can be mass produced, design tooling, fixtures, machines, and procure machine tools to do the work. They have to obtain materials and establish specifications and tolerances and verify that all the processes are capable of building consistant parts. Then they have to create procedures and processes that can be used to teach someone else to make the parts, usually workers who themselves are not highly skilled in engine design and manufacture. Then they have to debug manufacturing clitches and support production. All the while this has to be done keeping in mind the cost has to be competitive in the market, and things always have to be done quickly. That's a little different environment from one where the objective is to win races. A lot more compromises and trade-offs have to be made. It is pretty amazing that we can buy a chainsaw with the performace it has for only $600, or any other product for that matter.


all that and still have time to drive trains! must be a rough life :)
 
SIRCHOPALOT

SIRCHOPALOT

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some of my best friends are engineers, both the design kind and the train kind, I pick on them and they pick on me. its big fun. some of you guys need to loosen up a tad.. jeez.
 
TonyM

TonyM

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In college I saw some T-shirts someone had printed up. On the back it said, "Top ten reasons I want to be an engineer." Number 1 was, "I always wanted to drive a train!" Really, think about the origin of "engineer". Can you imagine some of the things that early train engineers had to do, likely in the middle of nowhere, with a fairly new technology, having to keep those trains going. I bet it took some pretty inventive and imaginative thinking to make repairs (in other word, cobbled together!).
 
TonyM

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And things pertaining to the college were badged "GMTE", pronounced "gumpty" for G.M. Technicians and Engineers. So the 25% of the students that were female were "GMTE girls".
 
SIRCHOPALOT

SIRCHOPALOT

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I had a few Friends that were there in the early nineties. all I ever heard was how hard up for love they were. seemed they would go out with anything that had legs. (number of them was an option, not a discretion).
 

Lobo

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SIRCHOPALOT said:
I had a few Friends that were there in the early nineties. all I ever heard was how hard up for love they were. seemed they would go out with anything that had legs. (number of them was an option, not a discretion).

I hope it was female legs. :laugh:
 
SIRCHOPALOT

SIRCHOPALOT

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one was Allen Hollinger from dayton area. He might have been in 95 also. He always brought freinds to the races with him. Pat was one and I can't remember some of the others, everything is still fuzzy from all the beer we drank.
 
TonyM

TonyM

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The name doesn't ring a bell, and I can't find it in my freshman yearbook. Maybe he is younger than I. As for the beer and women, I tried to avoid both while there. I stuck to studying and riding dirt bikes.
 
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