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Small compressor problem

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  • Small compressor problem

    Hi folks,

    I have a small compressor - the portable kind with a 15ltr or so tank - and it's a few years old and quite dusty.

    I decided it would be worth servicing it just to keep things smooth.

    I stripped it and re-greased the bottom end bearing and cleaned some gunk of the cylinder head.

    The cylinder head has a 'reed valve' type system for controlling flow in and out and a paper type gasket which got destroyed during removal.

    I cleaned everything up, removed some gunk from the thin metal reed things, and made a new paper gasket from a cereal box, popped a few drops of oil in the cylinder and reassembled.

    It runs nice and smooth, pretty quiet, and charges quickly up to about 100psi but then charges reaallllly slowly towards 110psi, never quite reaching 115psi (the cut off point).

    If I kill the motor and leave it at 110psi it never leaks at all.

    Any idea what the problem could be?

    The piston doesn't have an small end bearing in it (it's rigid on the conrod), it just wobbles, and has quite a big rubber piston ring which keeps the seal.

    I guess either that seal is no longer doing it's job (maybe my oil was a mistake?) or somehow the reed valve system isn't working 100% right, or maybe my paper gasket hasn't worked?

    No idea which it could be though and it sounds like it'd take hours to try them all! Would appreciate any suggestions or advice from anybody who's done this before.


  • #2
    It sounds like an OIL LESS design, they are disposable. Adjust the cut off point to 100 psi and be happy with that!


    • #3
      New head gasket

      'Ya gots to have compression increase, governed by 'clearance volume'. You have not changed anything from original--------with exception of the head gasket ie. cereal box top. Redo with new gasket of same or thinner thickness of the original.

      Don't bend, alter, damage the reeds when 'cleaning'.

      That oughta' drill.



      • #4
        I'm guessing that your cereal box gasket leaks. Buy a sheet of cut-it-yourself-gasket, that is designed for this application and actually compresses a little when you tighten all the cylinder head bolts.
        Amount of experience is in direct proportion to the value of broken equipment.


        • #5
          Try making the gasket out of a grocery bag smeared with Permatex. Worked for me.
          Any products mentioned in my posts have been endorsed by their manufacturer.


          • #6
            Paper gasket material coated with standard shop grease works wonders for me on exhaust/intaket gaskets.

            With the added chance the paper might just release from the metal someday when you gotta take it apart, without ripping everything.

            (Grease is half a sealing agent, half a release agent)
            Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


            • #7
              I have done a few of those.
              Paper cut it yourself seals works well but keep it thin espescialy round the reed valves.
              I normally use .25mm paper that works well.
              Also make sure your seals are spotless and have not burrs or dents.
              DO NOT use gasket maker in a tube. I scored a working compressor from a friend just cus he did that and glued his valves in the open position.

              If you are using violence and it does not work, You are not using enough or it is upside down.
              You can always just EDM it...