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  1. #1

    Question Exhaust port polish , without porting?

    Hello!

    I have seen some pics of those pretty hot looking ported cylinders from lowell and woody (freaking excellent job! and very good reputation). I see the exhaust ports are mirror polished. I don't have a budget right now, to pay a good porting job as I would would like to. But since my cylinders are outside, yet I thought I could do some polishing to the exhaust ports without changing the dimensions.

    The question is: will polishing alone give me any noticeable gains? some rpms or maybe better acceleration?

    -Chris


  2. #2
    WATER WOODY's Avatar
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    gimme a call chris...775-315-0222

  3. #3
    Pistonwash's Avatar
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    No.

    I am afraid not..you've got to physically change the way the ports are to get any results.

    Just save up your $$ and get a port job from Woodster or Lowell...you'll never regret it.


    Quote Originally Posted by chris1200 View Post
    Hello!

    I have seen some pics of those pretty hot looking ported cylinders from lowell and woody (freaking excellent job! and very good reputation). I see the exhaust ports are mirror polished. I don't have a budget right now, to pay a good porting job as I would would like to. But since my cylinders are outside, yet I thought I could do some polishing to the exhaust ports without changing the dimensions.

    The question is: will polishing alone give me any noticeable gains? some rpms or maybe better acceleration?

    -Chris

  4. #4
    32 Valves To Love! Racecar_Dave's Avatar
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    Quote Originally Posted by Pistonwash View Post
    No.

    I am afraid not..you've got to physically change the way the ports are to get any results.
    removing casting flash is physically changing the ports.

    I can't see how reducing turbulance would result in no change.

  5. #5
    PolarisNut's Avatar
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    Quote Originally Posted by Racecar_Dave View Post
    removing casting flash is physically changing the ports.

    I can't see how reducing turbulance would result in no change.
    If you want to get technical, yes, removing casting flash is a physical change, but it's no where near significant enough to notice a difference. The primary reason to polish the exhaust port is to prevent carbon from sticking...I've never seen a definitive RPM change by going from a semi-rough finish to a mirror finish, FWIW. If you know anything about airflow, you know that a boundary layer is created on the port walls when air/fuel flows through, so a slightly textured surface doesn't create harmful turbulence. You will have to change the exhaust port size and shape to see a gain.

  6. #6
    zpeters's Avatar
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    SEND TO WOODY!!!!!!!!!

    WORTH EVERY DIME (my arms hurt a little bit) Hopefully more when broken in!!!

    My build is coming !

  7. #7
    32 Valves To Love! Racecar_Dave's Avatar
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    So if his cylinders are out and he doesnt have the budget for a port job why would you advise him against polishing his ports. doesnt carbon buildup on the ports cause turbulance, restriction, loss of power and RPM? and cant it cause powervalve problems? so if no carbon builds up on his smooth exhaust ports that'll allow the hot exhaust air to escape faster, smoother, free-er?

    Chris - Im sure you could go to any auto machine shop and ask them to spend 20min a cylinder to clean up the casting flash. I cant possibly see a downside to this at all. an improvement, however small, is still an improvement.

  8. #8
    One day at a time..... N8R's Avatar
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    Or you can just do the "cheater porting " by stacking the gaskets under the cylinders..

  9. #9
    sleeplessnMS's Avatar
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    Or full porting with stacked gaskets!

  10. #10
    Interesting...mixed opinions but the pros are doing it, I guess it will not hurt.

    what do you mean by gasket stacking?, have you guys actually test it? what did you do? use two or three gaskets? is it a Noticeable difference?

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