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Duratec ring flutter and blow-by.

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  • Duratec ring flutter and blow-by.

    I ran into Ken Andersson from Cosworth this weekend and told him about my ring flutter experience I had on the dyno. As a recap, this happened at 7500 RPM (wide open throttle) and is a harmonic vibration in the rings allowing oil to bypass them into the combustion chamber with the predictable smoke show as a result.

    Ken said that this happens with many new Duratecs, even the Atlantic series ones. Most of them stops doing it once they get some wear on them (mine had 10 hours on it when it happened), while a few keep having the issue throughout the life span of the engine. It is apparently a Duratec thing. He told me that in a few of the engines they rebuild they can actually see different zones of wear along the length of the cylinder bore due to prolonged flutter.

    Once my race seat is in, I'll up the rev limiter to 7800 and have a friend drive behind me as I do another high rpm test to see if the problem has gone away now that the engine is broken in.

    /Magnus F.

  • #2
    You could try opening up the lower piston ring gap a fraction of a mm. Since my engine showed similar oil smoke at high revs (but probably for different reasons) I read up about piston ring flutter and some people recommend this to prevent pressure buildup between the first and second ring. That may cause a loss of radial pressure that keeps the ring sealed against the piston wall.

    Disclaimer: no idea if this is BS but I found it on 2 or 3 web sites.

    Gert

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    • #3
      Originally posted by magnusfeuer View Post
      Once my race seat is in, I'll up the rev limiter to 7800 and have a friend drive behind me as I do another high rpm test to see if the problem has gone away now that the engine is broken in.

      /Magnus F.

      Why not just continuously rev it up in your garage and ask your neighbors if the problem has gone away?
      www.morgansegal.com

      The funny thing is my wife goes " What is that car a Morgan ? " and I said "No that's a Caterham but there is a Morgan driving it " -delise

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      • #4
        Ken said that this happens with many new Duratecs...
        Odd, I haven't read any buzz about ring flutter on BC, w/ regard to either 2 liters or 2.3s. And they've been installed into a fair number of cars for a fair number of years.
        Chris
        ------------
        A day you don't go a hundred is a day wasted

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