oil blowby

Discussion in 'Engine, Fuel and Exhaust' started by murf, Jul 18, 2011.

  1. murf

    murf Active Member

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    I have a friend that recently acquired a 1986 EG Classic Liberty edition from his brother. This bike has had blowby problems for some time. His brother has redone the top end stock and my friend has spent around a $ grand in attempts to cure the problem. My question is this : I read an article in American Iron magazine about installing a S&S cam cover that would and has fixed this problem. What are your thoughts and what is different about this cam cover from stock that would fix the problem.
     
  2. glider

    glider Veteran Member

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    Blow by issues are associated with worn piston rings. The only cure for that is to replace the rings and hone or replace the cylinders. Anything else is just a band aid.
     
  3. RibEye

    RibEye Junior Member Contributor

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    Easiest mistake to do is to put the oil scavenging ring on upside down. Might this be possible here?

    Enjoy,
    Rich P
     
  4. Jack Klarich

    Jack Klarich Expert Member

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    Also check the routing of the oil hoses, if one is on the pump wrong you could have problems
     
  5. HarryB737

    HarryB737 Junior Member

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    +1 Rich,

    I have a friend at work that rebuilt his 350cu in Camaro & did that very thing on 6 of his 8 cylinders... needless to say he practiced the 1st time... :swoon
     
  6. murf

    murf Active Member

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    I'm inclined to think it's not the rings although anything is possible. As I stated this engine's top end was recently redone by a H-D tech.
     
  7. Jack Klarich

    Jack Klarich Expert Member

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    Just for giggles, check the breather gear and screen as long as you plan to change the cam cover check the spacing of the cover and timing of the breather:s
     
  8. Check the cam cover itself, it may have been replaced at some time with the wrong one. if the case has a walled off seperate cavity for the breather gear. the cover needs to also have the matching walled off portion. its hard to describe without having a gasket to show you. And the gasket too needs to seal the area off. the wrong gasket installed that does not seal off this cavity can cause the problem. the gasket looks like the outer dimension of the cover with an extra walled box in the lower left corner.
     
  9. glider

    glider Veteran Member

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    Jack made a good point here, the breather gear may have been installed and not timed to the engine properly. That would cause excessive pressure in the case.
     
  10. blademan

    blademan Active Member

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    I tend to agree with this. I had a shovelhead that was built properly and had excessive blowby. I tried everthing you can think of except this and never did get rid of the blowby. I had been told it could be the cam cover but didn't want to spend the cost of a new one on a maybe.