Stuffing Box issues

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  • What Anchor
    Senior Member
    • Oct 2016
    • 26

    Stuffing Box issues

    I completely rebuilt my 1962 A4 and it runs perfectly. The problem is the alignment and stuffing box. I guess naval architects never gave any thought to the fact that someone will have to work on the engines and prop shafts. Anyway, I decided I was not getting enough of a drip so I loosened the jamb nut and backed off the box about 1/2 turn and retightened, or so I thought. The jamb nut backed off and I nearly sank the boat. All is well now except still not getting the drip or two every minute, so I put an infrared thermometer on the box after it had ran about a mile and it was about 90 degrees. Does this seem right? I sail on Lake superior and the water temp is now about 65, so it made sense to me, but what do it know. Does anyone know what the temps average. The shaft is only a 3/4 so the box is tiny and I could only get two wraps of the oakum in it.
    Thanks
    Carl
  • What Anchor
    Senior Member
    • Oct 2016
    • 26

    #2
    After I posted this I did an internet search and found some info saying no more than 30 degrees above water temp. they also said the temp is more important than the drip, makes sense. However, I would still like to hear from this forum as I consider many here to be very knowledgeable.

    Comment

    • JOHN COOKSON
      Afourian MVP, Professor Emeritus
      • Nov 2008
      • 3500

      #3
      The stuffing box should run the same temperature as the surrounding water. If you can't get satisfactory temperature at a drip rate you are happy with ( I like
      ~ 6 drops per minute) then you will need to repack.
      It sounds to me like you need to loosen the packing nut a tad. Also you will most likely have to adjust the packing nut a few times until the new packing is broken in.

      TRUE GRIT

      Comment

      • Al Schober
        Afourian MVP
        • Jul 2009
        • 2007

        #4
        In my experience, loosening the packing nut doesn't do much to loosen the packing. Once it gets jammed in there, it tends to stay there. You'll likely have to start with fresh packing, then tighten it up little by little.
        Two rings of packing is plenty. We're not talking high pressure here. Navy submarines use packing in the reactor feed pump (1000 psi or so) and only 5 rings.
        Don't know what you're using for packing. Look for stuff called Keystone packing. Most packing is square, and when you wrap it around the shaft it distorts - no longer square. Keystone packing starts off with a keystone shape. You put the narrow edge against the shaft, and when you wrap it, it becomes square - like magic!
        Replacing packing is not hard. Often poor access makes it difficult, bordering on painful.

        Comment

        • roadnsky
          Afourian MVP
          • Dec 2008
          • 3101

          #5
          Agree with Al...
          once the packing is jammed up (and hardened) it's best to re-pack.

          You can do it while in the water easily.
          I like to use RESCUE TAPE wrapped around the tube threads, while re-stuffing.
          It lessens the incoming water flow to a trickle (or even none) so you can take your time.
          This is also a good emergency stop gap if your stuffing box lets loose on you.
          Attached Files
          -Jerry

          'Lone Ranger'
          sigpic
          1978 RANGER 30

          Comment

          • What Anchor
            Senior Member
            • Oct 2016
            • 26

            #6
            Thanks for all the great advice, I will repack and see what that does.

            Comment

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