When to replace piston rings

Discussion in 'Engine, Fuel and Exhaust' started by fabrozor, Mar 1, 2010.

  1. fabrozor

    fabrozor Active Member

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    I will soon open the engine (heads, cylinders, ...) at 40000 miles.
    I was Recommended not to change the piston rings.
    How does it sounds to you. ?
    When do you recommand to change the piston rings ?
    Thanks.
     
  2. fabrozor

    fabrozor Active Member

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    i open because i have the valve stem leak problem.
    The combustion chamber and the piston are covered with black oil bad combustion residue.I want to clean.
    - So i remove the head, to clean the head.
    - I remove the cylinder to clean the piston. I dont want to clean the piston without removing the cylinder to not let the combustion residue i will remove, go in between the piston and the cylinder wall. And as i will remove the head, i think the bottom gasket under the cylinder will need to be changed.
     
  3. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    If you are dissassembling the top end for other reasons, it makes sense to do a complete top end job. Valve job, valve guides, new valves if stems scored or damaged, heads dipped, jugs honed, pistons dipped, new rings, new gaskets, orings and seals (top end kit).

    Remember that once back together, you will need to follow a good break-in procedure. Check this:

    Engine Break In For New Motors - Harley Davidson Community

    TQ
     
  4. fabrozor

    fabrozor Active Member

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    i thought to just change valve stems on both heads, gaskets on boths heads and cynlinders.
    An let the old rings on the pistons like it was recommanded to me.
     
  5. gs34

    gs34 Junior Member

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    The top of the pistons get black and crusty naturally. As long as it is not excessive, and with only 40,000 miles I wouldn't think it would be, I would not mess with the tops of the pistons or the cylinders.
    I would put valve seals in it and run it.
    That little crust build up on the piston crown will not effect the operation of the engine one bit.
    If it was mine, that is what I would be doing.
     
  6. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    IMO, to go to the effort of pulling the heads and the jugs off and NOT doing a top end job does not make sense. The manual will indicate that you need to replace the cylinder studs and cylinder head screws as well as all the gaskets, orings, and seals. Why not do the complete top end job so that is all back to "new" condition and you do not need to worry about it for a while. If you were not removing the heads, it would be a different matter, but to do the job you indicate needs to be done, that is required. So like I said, if it were my engine, I would do the top end job: clean everything, valve job, rings, have cylinders honed.

    TQ
     
  7. fabrozor

    fabrozor Active Member

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    Thank you for your recommandations, it's good for me to have your points of view in the balance.

    @gs34 :
    Last time i cleaned the spark plugs, they were cover with half an inch of this black residue. So i guess in the head and on the piston there is more of this black this than there should be.

    @TQuentin1 :
    I know the good way to do it is to do like you say. I would like to do like you say. The problem is i also have the cam chain tensioner problem and i orderer all the necessary parts at Herko and beside this i baught tools and with the taxes and shippment now it's a 3200 US.$ bill.
     
  8. gs34

    gs34 Junior Member

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    If it is as bad as you saythen I agree with TQ. If you are that far into it. It is foolish to not do the job complete.
     
  9. BUBBIE

    BUBBIE Well-Known Member

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    MAN WHAT ARE THE TAXES....
    I would think for 3200$ us i could have ALL NEW PARTS::::: BIG BORE PISTONS n RINGS,HEADS, NEW CYLENDERS. CAMS and CAM CONVERSION KITS/TOOLS......
    signed....BUBBIE
     
  10. fabrozor

    fabrozor Active Member

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