Engine Drivetrain 2nd Gen S Stuck Piston Ring Scenario

Discussion in 'Tuning and Performance' started by genik, Apr 5, 2014.

  1. genik

    genik Member

    Feb 20, 2012
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    Supposing an R56S piston ring gets stuck and doesn't work as should, what could the possible results be, the possible scenario?
     
  2. MCS02

    MCS02 Moderator
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    It depends. It would more than likely be down on compression on that cyclinder, it may pump oil so it will smoke, among other things.
    Why do you ask?
     
  3. genik

    genik Member

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    Please elaborate when you say other things! For example could oil be pumped out, sprayed all over the engine?
     
  4. ZippyNH

    ZippyNH Well-Known Member

    Jan 25, 2010
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    Would be unusual for one to get stuck on an engine that has not been stored....especially with modern oils...they don't tend to turn to thick tar and sludge.....
    Results...much like the threads of folks with failed pistons around the wrist-pin in the skirt area...very high blow by....maybe a long cranking time...poor results in a compression AND leak down test.....
    P.S.
    The pistion rings used in a turbo/sc motor (which is desgined to be that way from the factory) has very heavyvrings compared to a na motor....the main reason "breaking in" a turbo/sc motor is so important IMO....you want then to "seat...not ground to fit" to ensure reasonable oil consumption.....
     
  5. DneprDave

    DneprDave Well-Known Member
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    If it is blowing oil all over the engine, you probably have a bad PCV valve.

    Dave
     
  6. genik

    genik Member

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    ZippyNH thanx so much for the help, i have a feeling you are correct, but please since im no tech, nor is English my native language, can you make your suggestions more clear for amateurs/foreigners like me to understand? :confused5:
     
  7. genik

    genik Member

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    #7 genik, Apr 5, 2014
    Last edited: Apr 5, 2014
    Thanx Dave, i just want to say (if it might be of help) that this doesn't happen every day, car has done 80000km and its the 2nd time this happens.
    Whats the PCV valve responsible for?
    Is there a way to test it, to see if its faulty?
     
  8. DneprDave

    DneprDave Well-Known Member
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    The PCV(Positive Crankcase Ventilation) valve vents cylinder blow by gasses out of the crankcase, so the crankcase doesn't pressurize and blow oil out of your oil seals, gaskets and dipstick hole. On a second generation Cooper S it is part of the headcover, on the top of the engine. It vents crankcase pressure to the turbocharger intake, when the engine is under boost and to the intake ports when not boosted.

    Yours may be sticking intermittently causing the occasional mess.

    Dave
     
  9. genik

    genik Member

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    - How can i check to see and make sure 100% that this is the problem and its not a stuck piston ring or something else?
    - After i make sure and are certain that those PCV valve vents are the issue, how can they be cleaned or fixed?
     
  10. ZippyNH

    ZippyNH Well-Known Member

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    Some old cars are driven for many miles with VERY worn pistion rings ....these cars typically have very high "blow-by" ...which means high crankcase pressures....as long as the pcv is doing its job....no mess. In cases where the oil cap has air blowing out when closed or a dipstick that gets blown out....I'd bet there are other issues.
    Remember....pistons rings to not go the full 360° around a pistion..that is why there is more than one...in odd cases the slots in them can line up....but the blow by is still limited.
    The PVC on gen 2 mini's are an odd thing....
    Depends on the year of the car....some you must replace the valve cover to replace a pcv valve....
    Are you running a catch can....done wrong...that can cause issues...same for the popular pluggingbof a pcv vent....
    What are you symptoms?
    Describe the "mess".... What happens?
    Running a tune?
     
  11. DneprDave

    DneprDave Well-Known Member
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    A compression test would tell you if it is rings. They say you cannot clean the PCV valve on series two MINIs, but that wouldn't stop me from trying. It is part of the head cover and the whole assembly has to be replaced, it costs two or three hundred dollars.

    Dave
     
  12. genik

    genik Member

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    Can blocked PCV valves be responsible for oil burning or white exhaust fumes when starting the motor?
     
  13. genik

    genik Member

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    no catch can
    car is standard
    engine oil level is down a quart after 500km
    oil sprayed all over motor for the 2nd time
    what else do u wanna know? :)
     
  14. MCS02

    MCS02 Moderator
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    I would do a compression check.
     
  15. ZippyNH

    ZippyNH Well-Known Member

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    Where is the oil coming from? Is it getting blown out the dipstick or another location that leads you to believe that crankcase pressures are too high?
    When did it get oil sprayed all over? High rpm high boost pull?
    My guess....pcv valve is sticky as suggested above...
    Gen2 motors can burn quite a bit of oil....but I have seen SEVERAL valve covers replaced when down at the local shop for pcv issues.....
    But a compression check/leak down test is cheap and easy....about the same as doing a set of sparkplugs...will tell you if it is a ring or piston and or valve issue as opposed to pcv issues....
    Then you can take it from there....more info will help you spend $$ wisely....
     
  16. genik

    genik Member

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    Its not from the dipstick.

    Well i was driving it a bit hard!

    How can i check for this, if it is sticky? Doing the compression test?

    Can a PCV valve be cleaned?
     
  17. MCS02

    MCS02 Moderator
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    You can also pull your pluge and see how they look. If they all look good then it probably is not a ring.
     
  18. ZippyNH

    ZippyNH Well-Known Member

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    ok....were is it coming from?
    Kind of an important bit of info....
     
  19. genik

    genik Member

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    Well this is how the motor looked like that day
     

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  20. oldbrokenwind

    oldbrokenwind Active Member

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    R56S PCV's CANNOT be cleaned! This PCV system is an integral part of the valve cover, and even trying to examine the system visually is a destructive process.

    You want more info, let us know where the oil is leaking from. A list of mods, if any, would also be helpful.
     

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