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piston rings or ptfe packing

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piston rings or ptfe packing

Home › Forums › Stationary engines › piston rings or ptfe packing

Viewing 8 posts - 1 through 8 (of 8 total)
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  • 27 January 2012 at 19:37 #83212
    Kevin Bennett
    Participant
      @kevinbennett25223

      Hi am still making my scratch build of a Stuart 10V from a book what is best with a brass a piston rings or ptfe packing for a Stuart 10V

      Thanks Kevin

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      27 January 2012 at 19:37 #3116
      Kevin Bennett
      Participant
        @kevinbennett25223
        27 January 2012 at 20:10 #83217
        Dusty
        Participant
          @dusty
          Kevin
          More to the point what is your cylinder made of? Do you mean brass or is the piston gunmetal or bronze. The brasses that we normally use are not good bearing materials, you will find that a brass piston will wear quite quickly if given a reasonable amount of use. If your cylinder is of brass then you have no real option but to use soft packing or ‘o’ rings, piston rings will have a tendency to wear the bore as they will need to be made of a disimilar material (cast iron rings in a cast iron cylinder are O.K.) brass/bronze/gunmetal rings in a cylinder of the same material will have a propensity to pick up. Personaly I would use graphited yarn packing.
          27 January 2012 at 20:15 #83219
          JasonB
          Moderator
            @jasonb
            Couple of oil grooves should be enough, thats what the original has.
             
            J
            27 January 2012 at 20:19 #83221
            Kevin Bennett
            Participant
              @kevinbennett25223
              hi Dusty the cylinder is fine grain cast-iron also i have not made the piston yet
               
              TY Kevin
              27 January 2012 at 20:44 #83227
              Sub Mandrel
              Participant
                @submandrel
                Kevin – I used graphited yarn for mine, but since then I have used ‘nitrile’ o-rings. Brass or gunmetal pistons in cast iron cylinders.
                 
                Neil
                28 January 2012 at 09:35 #83250
                Alan Reed 1
                Participant
                  @alanreed1

                  My 10v works well with the oil grooves as per the Stuart drawing.

                  29 January 2012 at 09:59 #83329
                  Dusty
                  Participant
                    @dusty
                    Kevin
                    If you have a nice cast iron cylinder I would use a cast iron piston and as a couple of the guys have said oil grooves should be enough. Make the piston slightly on the stiff side in the cylinder bore, then polish the piston with some fine wet and dry say 800 grit
                    back this with a 6″rule to keep it flat (you don’t want a convex piston) when it is a nice sliding fit pat yourself on the back. Take care with the wet’n’dry it is amazing how fast you can remove a couple of thou.
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