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Volvo AQ280 outdrive exhaust bellows - do I need one with a flapper?

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    Volvo AQ280 outdrive exhaust bellows - do I need one with a flapper?

    I'm in the process of changing out both exhaust and u-joint bellows on a Volvo 280 outdrive (on a 1980 Bayliner 2550 Saratoga Offshore). Most part numbers I've looked up refer to Volvo #876631 or 50050 (not sure which I need). The bellows I removed has a built in flapper, but I don't believe the replacements have it. Do I need one with a flapper and if so what part number (and maybe resource). Along the same line, the replacement U-joint bellows looks to be part # 876294 but the one I removed is clearly stamped as Volvo Penta 872281.
    1980 2550 Saratoga Offshore
    Volvo Penta AQ260 (350 chevy) 280 outdrive

    #2
    Also to note: I did have a small amount of clean oil in the bottom of the exhaust bellows when I removed it. Is this normal or trigger something else to look at while I have it apart?
    1980 2550 Saratoga Offshore
    Volvo Penta AQ260 (350 chevy) 280 outdrive

    Comment


      #3
      With the V-8, I would forgo the flapper in the bellows ...... it is too restrictive!
      I would retrofit a 290 flapper to your 280 exhaust outlet (been there/done this many times).
      This will require cutting away the “bump” on the outlet area.
      You will also need to remove just a bit of the flapper material in the center.

      It will work great!





      Rick E. Gresham, Oregon
      2850 Bounty Sedan Flybridge model
      Twin 280 HP 5.7's w/ Closed Cooling
      Volvo Penta DuoProp Drives
      Kohler 4 CZ Gen Set

      Comment


        #4
        Hi Rick.. how does the conversion actually work. If I decide to forgo the conversion for a later time, can I just install the bellows without a flap for now? Any thoughts regarding the small amount of oil I found in the bottom of the u-joint bellows (probably about 1/16 of a cup)
        1980 2550 Saratoga Offshore
        Volvo Penta AQ260 (350 chevy) 280 outdrive

        Comment


          #5
          ..................
          Originally posted by btubb View Post
          Hi Rick.. how does the conversion actually work. If I decide to forgo the conversion for a later time, can I just install the bellows without a flap for now?
          Doing so would leave you without any back-flow prevention.

          Reason for having a back-flow prevention flapper in place:
          Upon quick deceleration, wave surge can push water into the open and un-checked exhaust area.
          While sitting still, wave surge from another boat can push water into the open and un-checked exhaust area.
          If this was to occur, the water may make it's way up and over the exhaust passage within the exhaust system elbow, and into an open exhaust valve.
          It may not hydro-lock the engine, but it may warp a hot exhaust valve!



          And again, keep in mind that the internal exhaust bellows flapper is very restrictive for a V-8 engine. In other words, the internal bellows flapper will cause engine performance to suffer!


          Any thoughts regarding the small amount of oil I found in the bottom of the u-joint bellows (probably about 1/16 of a cup)
          Yes.... most likely an issue with the main drive gear seal!
          You will want to drain the gear oil and perform a Pressure/Vacuum "leak-down" test!

          To replace this seal, the transmission must be disassembled. I.E., the main drive gear bearing box must be removed!


          DO NOT attempt to remove the 4 clamping collar cap screws without first applying heat to the threaded areas.




          Volvo Penta did offer a 280 exhaust outlet back-flow prevention flapper on some production models only.
          This flapper could not be purchased over the counter.
          It is rare to see one on a lower unit!
          I do have one if interested!

          Otherwise, retro-fitting the 290 flapper is a good option, and it is not too difficult to do.





          Click image for larger version  Name:	Volvo Penta 280 to 290 flapper retro-fit.jpg Views:	0 Size:	306.1 KB ID:	493828
          Rick E. Gresham, Oregon
          2850 Bounty Sedan Flybridge model
          Twin 280 HP 5.7's w/ Closed Cooling
          Volvo Penta DuoProp Drives
          Kohler 4 CZ Gen Set

          Comment


            #6
            Thanks again Rick. It appears the flapper retrofit is pretty straight forward. However, I've been unable to find the part. Do you have a part number or source? As for the drive gear seal, is there a way to do a pressure test to confirm if the transmission is already off but not disassembled? I assume if the 4 clamping collar cap screws can be easily removed, no heat would be needed or needed in either case?
            1980 2550 Saratoga Offshore
            Volvo Penta AQ260 (350 chevy) 280 outdrive

            Comment


              #7
              .....................
              Originally posted by btubb View Post
              Thanks again Rick. It appears the flapper retrofit is pretty straight forward.
              Yes, it is!

              However, I've been unable to find the part. Do you have a part number or source?
              I should have a good used 290 flapper (pn 852644) and the SS plates.
              I do have a good used 280 flapper (pn NA) and the SS plates. This would require drilling the holes for the SS Pop Rivots only.


              As for the drive gear seal, is there a way to do a pressure test to confirm if the transmission is already off but not disassembled?
              Not unless you have a custom built fixture as I do!
              Otherwise, the transmission must be in place on the Intermediate housing.


              I assume if the 4 clamping collar cap screws can be easily removed, no heat would be needed or needed in either case?
              Here's the deal.....
              The 4 280 clamping collar bolts (cap screws) are wet area bolt threads.
              The bolts (cap screws) are carbon steel.
              Carbon steel rusts when exposed to water for long periods.
              Rust will prevent easy removal of these cap screws.
              Heat will help you safely extract them without rounding out the hex sockets!

              If you attempt to loosen these without heat (at the threaded areas), and if they are stuck, you will likely round out the hex sockets.
              If you round out the hex sockets, you will be taking the transmission to a machine shop for a milling machine extraction of the hex heads.
              This alone can run into a $100+ expense..... and that's only if they are familiar with doing this!
              Plus, if the machinist damages the delicate aluminum hex head shoulders (within the collar itself), you will loose the hex head water seal.
              Next, you will be buying a new clamping collar, plus you will need to go through the critical shimming procedure for the new collar.

              Trust me..... whether you think that you need it or not....., heat is your friend on this!
              You've got nothing to loose but a bit of Propane or Mapp Gas fuel and a few minutes of your time!

              NOTE: NO Oxy/Acet heat...... it will produce far too much heat!

              Rick E. Gresham, Oregon
              2850 Bounty Sedan Flybridge model
              Twin 280 HP 5.7's w/ Closed Cooling
              Volvo Penta DuoProp Drives
              Kohler 4 CZ Gen Set

              Comment


                #8
                Thanks once again Rick. No more convincing needed... heat it is!! I'm going to dive into this outdrive service and will start on a parts list that I'll need so I can get them ordered. I'm planning on replacing u-joints (with the Spicer # 5-1306X I keep reading about) main drive seal, upper and lower bellows, water intake "S" hose and fitting. I am interested in your 280 flapper and plates. Let me know how to go about that. What parts should I expect to order to complete the job. Thanks again for the much needed assistance!
                1980 2550 Saratoga Offshore
                Volvo Penta AQ260 (350 chevy) 280 outdrive

                Comment


                  #9
                  ...............
                  Originally posted by btubb View Post
                  Thanks once again Rick. No more convincing needed... heat it is!!
                  Glad to hear that. A small Propane or Mapp gas torch will do the trick!


                  I'm going to dive into this outdrive service and will start on a parts list that I'll need so I can get them ordered. I'm planning on replacing u-joints (with the Spicer # 5-1306X I keep reading about)
                  Yes.... the Spicer 5-1306X (if you can still find them) is a good Bearing Cross replacement.

                  main drive seal, upper and lower bellows, water intake "S" hose and fitting. I am interested in your 280 flapper and plates. Let me know how to go about that. What parts should I expect to order to complete the job. Thanks again for the much needed assistance!

                  Shoot me a PM with your email address.
                  Rick E. Gresham, Oregon
                  2850 Bounty Sedan Flybridge model
                  Twin 280 HP 5.7's w/ Closed Cooling
                  Volvo Penta DuoProp Drives
                  Kohler 4 CZ Gen Set

                  Comment


                    #10
                    Rick... PM sent. It appears the Spicer 5-1306X has fallen off the face of the earth - I can't find 'em anywhere and from what I've read, I should steer clear of cross referenced u-joints. Do you know another option?
                    1980 2550 Saratoga Offshore
                    Volvo Penta AQ260 (350 chevy) 280 outdrive

                    Comment


                      #11
                      Originally posted by btubb View Post
                      Rick... PM sent. It appears the Spicer 5-1306X has fallen off the face of the earth - I can't find 'em anywhere and from what I've read, I should steer clear of cross referenced u-joints. Do you know another option?
                      The Spicer 5-1306X (early Chrysler auto application) has the grease fitting in the apex of the cross. The X designates this!

                      A marine stern drive bearing cross (aka U-joint) does not articulate quite as much as an auto application bearing cross does. The bearing cap tends to "point load" against the cross trunion, which means that adding grease becomes more about that "feel good feeling" than it does about preventing wear.
                      In other words, and IMO..... no amount of future grease will prevent point load wear!

                      You can forgo the grease fitting by using a similar Spicer (early Chrysler auto application) without the grease fitting.



                      .
                      Rick E. Gresham, Oregon
                      2850 Bounty Sedan Flybridge model
                      Twin 280 HP 5.7's w/ Closed Cooling
                      Volvo Penta DuoProp Drives
                      Kohler 4 CZ Gen Set

                      Comment


                        #12
                        That is good information. What u-joint would you suggest in its place? Has anyone kept a parts “shopping list” to complete this job? I would want to make sure I order everything correctly.
                        1980 2550 Saratoga Offshore
                        Volvo Penta AQ260 (350 chevy) 280 outdrive

                        Comment


                          #13

                          Originally posted by btubb View Post
                          That is good information. What u-joint would you suggest in its place?
                          This search shows a few Spicer 5-1306X cross references.

                          http://www.universaljoint-supplier.c...-vehicles.html


                          I would look for a US, German or Japanese made bearing cross.





                          Example and suggestion only. Please verify!

                          Click image for larger version

Name:	Spicer 5-1306X alternative.png
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ID:	494003

                          Rick E. Gresham, Oregon
                          2850 Bounty Sedan Flybridge model
                          Twin 280 HP 5.7's w/ Closed Cooling
                          Volvo Penta DuoProp Drives
                          Kohler 4 CZ Gen Set

                          Comment

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