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  • GregH
    Afourian MVP
    • Jun 2015
    • 598

    How Do I ....

    So.... got the A4 back in the Alberg 30, but trying to align the couplings is proving very frustrating in the small engine space.

    It's a different A4 than came out. I have some pics showing the old engine's shims at the flywheel end, but no pics from the transmission end. I have the rubber pads on but that seems to raise it way too high for proper alignment at the tranny end. The previous engine even had aluminium shims which I haven't added yet since the rubber pads look too much!

    1/ what size bolts and how long for mounting to the stringers ? Some were missing when I got the boat

    2/ any simple tips or tricks to make this easier ?

    3/ the 0.002 coupling tolerance- is this measured before bolting them together ?
    Greg
    1975 Alberg 30
    sigpic
  • Al Schober
    Afourian MVP
    • Jul 2009
    • 2031

    #2
    Greg,
    The 2 mil allowance is before bolting. After bolting, the gap will go to zero. The idea is to minimize the stress this causes in the shafting. Too much stress and the shaft will fail in fatigue.
    As I recall, my engine studs are 3/8". End into the stringers is like a wood screw, upper end takes a nut.
    No easy way to do it. Loosen the stuffing box and it's hose, then see where the limits of shaft motion are. I don't know your shaft configuration. If you have a strut, that will hold the aft end of the shaft - then just position the fwd end to be in the middle of the stern tube clearance. Don't have the shaft in a position where it's binding when you align the engine.
    Shims are good for vertical alignment (old Kem plastic playing cards work well). As for horizontal alignment (equally important), I like to get the engine where it wants to be then pack some Bondo between the studs and the holes in the oil pan. This keeps the engine from shifting side to side.
    Oh yeah, the A4 doesn't need rubber pads (or soft engine mounts). My engine is hard mounted and works fine.
    Last edited by Al Schober; 08-10-2017, 07:49 PM. Reason: mounts

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    • sastanley
      Afourian MVP
      • Sep 2008
      • 7034

      #3
      Originally posted by Al Schober View Post
      Oh yeah, the A4 doesn't need rubber pads (or soft engine mounts). My engine is hard mounted and works fine.
      +1..mine is directly on the fiberglass 'runners'.

      The front mounts are for fine tuning, the aft mounts are for gross tune when aligning the engine. The engine must align to the shaft when it is centered in the tube/stuffing box assembly (full keel right??, so no separate strut). This is where the 0.002" clearance comes in..that will get dialed in real quick as you go from gross tune and get it close, to fine tune.

      When I was re-assembling mine..I messed with it for hours, and got frustrated. I put the tools down for the day, and let it sit. Came back the next day, and had it all lined up in 1/2 an hour...I just had to come at it with a fresh mind.
      Last edited by sastanley; 08-11-2017, 10:27 AM.
      -Shawn
      "Holiday" - '89 Alura 35 #109
      "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!)
      sigpic

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      • GregH
        Afourian MVP
        • Jun 2015
        • 598

        #4
        Thanks for the bits of info. If I ever have to do it again I'll go the route of putting the studs in first, then lowering the engine onto them. My stringers have aluminum nut or threaded socket embedded. This time I used the old 3/8 hex bolts and so they have to go in after and the fun of aligning the holes!

        I'm on day three of alignment, as I have to sit and ponder how to returns engine to move x millimeter, or y millimeter lol. Finally got the aft port side bolt hole lined up but the bolt no matter what I do crossthreads, so on the weekend I'll chase the threads and hope that helps. I'm hoping once that's done the bolt under the water pump will just line up.

        The old engine had rubber pads and alum shims so I'll go with those to start.

        The forward bolting plates and stringers have two bolt holes but with the aft bolt holes lined up there is no way to get two bolts in the forward plates anymore. May be silly question but how important is gave two bolts per side atvthe fwd end?
        Last edited by GregH; 08-11-2017, 07:05 PM.
        Greg
        1975 Alberg 30
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        • GregH
          Afourian MVP
          • Jun 2015
          • 598

          #5
          Well I've gotten myself into a right mess with the engine mounting bolts in the Alberg.

          The aft port-side bolt was cross-threading in the embedded aluminum nut/insert so I chased the threads today hoping to fix it up and keep going. Well laying on top if the engine while trying to use the tap I ended up making it worse and now the 3/8" bolts won't engage at all.

          My options as I see them:

          1/ have the yard remove the engine and go back in drilling out the stringers for either:
          - fill with epoxy and tap again for 3/8 bolt
          - drill and tap for a 1/2" bolt
          - use a hanger bolts (lag bolt on one side / 3/8 regular bolt on the other)

          2/ leave the engine in place and using a 90D drill prep for options above or drill and switch over to a basic lag bolt

          Another option I may be missing did to my frustration ?
          Greg
          1975 Alberg 30
          sigpic

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          • sastanley
            Afourian MVP
            • Sep 2008
            • 7034

            #6
            Hmmm...my motor mounts are attached to fiberglass runners with lag bolts. I have two per mount...Some of them were loose and the fiberglass would not hold them, so some real thick epoxy was jammed in the hole and the bolt re-inserted before it cured.

            I don't think I understand why the motor mounts will not line up with the old holes in the boat anymore?

            Can you take some pictures?
            -Shawn
            "Holiday" - '89 Alura 35 #109
            "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!)
            sigpic

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            • GregH
              Afourian MVP
              • Jun 2015
              • 598

              #7
              Originally posted by sastanley View Post
              Hmmm...my motor mounts are attached to fiberglass runners with lag bolts. I have two per mount...Some of them were loose and the fiberglass would not hold them, so some real thick epoxy was jammed in the hole and the bolt re-inserted before it cured.

              I don't think I understand why the motor mounts will not line up with the old holes in the boat anymore?

              Can you take some pictures?
              Well I went back on Sunday with a fresh attitude lol.. took the water pump off and got that bolt inserted. Added the last two thin alum shims to the front of the engine. And the bolt holes are basically lined up. The aft port one is definitely stripped. So there are 5 of 6 bolts in and tightened down.

              To see how the shaft coupling lined up I tightened those three bolts down snug. At the bolts there is zero gap..midway between bolts it is 0.002, 0.0035, 0.0025

              So I am hoping that with leaving the engine in place I can drill out the stripped hole, fill with epoxy around a bolt longer than needed and once cured swap for a shorter bolt that can be tightened down.

              I'll get some pics within the next week
              Greg
              1975 Alberg 30
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