the art of engine

Discussion in 'Shiny Things' started by Loadedagain, May 21, 2005.

  1. Gimpinator

    Gimpinator This is my Mom's cat

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    ^^^^^ Offset crank.

    Yes. Henry Ford did an offset crankshaft on the production Flathead V8 starting in 1932. Offsetting to the thrust side does indeed give you a bit more mechanical advantage on the power stroke, but it makes it difficult to keep the pistons from slapping.
  2. vtwin

    vtwin Air cooled runnin' mon

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  3. pierce

    pierce Aven'Tourer

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    hmmm. thinking some more... its kinda hard to offset for power BOTH sides of a V engine unless its really asymmetrical. the drawings with the dashed lines for hte piston centerlines in that video showed both sides meeting at a point directly below the crank. to gain the thrust advantage, that virtual meeting point would need to be offset to the 'down' side of the crank...
  4. Gimpinator

    Gimpinator This is my Mom's cat

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    Actually offsetting the crank does work fine on a Vee engine. The crank is rotating the same way for both banks, so the big end of the rod is coming over the top to the same side. Offsetting the crank over to that side that the rod big end is moving (known as the Thrust Side) will get you the mechanical advantage on both banks.

    Reducing side load on the thrust side will make the pistons a bit noisier, but you can help that by offsetting the piston pin over as well. With an offset crank, there is also a bit of NVH due to the resulting uneven piston movement. This is the main reason it is not done on modern engines.
  5. LuciferMutt

    LuciferMutt Rides slow bike slow

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    THought you guys talking about offset cranks would find it interesting that the crank in Honda's new little CBR250R is offset to thrust side. Haven't heard about any piston slap issues with that engine yet.
  6. vtwin

    vtwin Air cooled runnin' mon

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    http://www.cbr250.net/forum/archive/index.php/t-1005.html:deal

    One of our club members has this bike and has complained of an engine rattle he claims people on the forums are talking about. He called it the "Death Rattle".
  7. ttpete

    ttpete Rectum Non Bustibus

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    Offset cranks have been around for over a hundred years. "Desaxe" is a term often used for the concept.
  8. LuciferMutt

    LuciferMutt Rides slow bike slow

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  9. rotten

    rotten LOST AGAIN

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    I had to dig this one up, one of my favorite engine test videos.

    http://www.youtube.com/watch?v=gSHToyGIxWE&t=6s

    <iframe width="420" height="315" src="http://www.youtube.com/embed/gSHToyGIxWE?rel=0" frameborder="0" allowfullscreen></iframe>
  10. papalobster

    papalobster With Gusto!

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    You would think with all the brain power in that room, someone would have thought to bring ear plugs.
  11. rotten

    rotten LOST AGAIN

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    :rofl
  12. kobudo28

    kobudo28 Banned

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    what?
  13. KrustyKustom

    KrustyKustom Lets Go....

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    One of my favorites!
  14. Renato CWB

    Renato CWB Adventurer

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    I took these photos at the memorial of Dutch immigration in Carambeí (Parque Histórico de Carambeí), Paraná, southern Brazil.

    [​IMG]

    [​IMG]

    I don't know if they are running :(:
  15. anotherguy

    anotherguy Long timer

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  16. Tork

    Tork Pinsetter

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    <iframe width="560" height="315" src="http://www.youtube.com/embed/e1ag3uLUWJE" frameborder="0" allowfullscreen></iframe>
  17. Vbird

    Vbird In Room 237

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    ^ Going to be in the US Fiesta next year according to Autoweek. Only thing that bothers me is the "maintence free" timing belt that runs through oil. :huh

    At the Ford Nationals last year I drove most of the cars/suvs they brought through an autocross course they had set up. Eventhough all were auto trans, the Fiesta was the most fun. A turbo 3 with a M/T would be a blast and get good mpg.
  18. Hughlysses

    Hughlysses Long timer

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    ^ Lots of interesting stuff in that video. The "wet" timing belt is definitely weird. Apparently the exhaust manifold is cast into the head, and it looks like the oil pump has some sort of variable volume control.
  19. 12ARX

    12ARX Long timer

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    And it's a highly strung 3 banger that will need oil changes regularly and the oil filter is in a shit of a spot...
  20. broncobowsher

    broncobowsher Long timer

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    I had to watch it a couple times, but the wet belt looks like it is really a chain that got poor CGI. If you look carefully there is a second chain that drives the submerged variable displacment oil pump.

    Ford has always had a thing for cast in manifolds, remember the old Falcon six?

    Interesting stuff? Was looking at a new Ford Hybrid last week, water jacketed exhaust coming off the head.