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Replacing Volvo Penta engine, should I rebuild SX drive while its apart?

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  • Replacing Volvo Penta engine, should I rebuild SX drive while its apart?

    I am replacing my old 215hp 5.0 GL in my 2004 Larson Lxi 210 with a new 320hp 5.7 engine. I have done engine and transmission swaps in cars, as well as rebuilt an engine and a T56 transmission, however boat repair is new to me, so I need pointed in the right direction. To remove the engine I understand that the Volvo SX outdrive needs to come out first as well? Any tips on the proper way to do this?

    What maintenance should I do to the outdrive while it is out? Last season I had some delayed shifting, mostly into reverse, where I would put it into gear and it would not do anything for a few seconds, then grab hard and finally go into gear.. I understand that this could be the cone clutch going out?

    I also want to inspect the exhaust risers as well to make sure that they are good as well, as I am converting from raw water to closed cooling when I put the new engine in, so I want to make sure that the risers don't have any leaks and take out the new engine. What's the best way to test these out while I have them off?

    Anything else that I may be missing here or tips while doing the engine swap?

    Thanks in advance!

  • #2
    Speaking for myself and my mechanical abilities, I would not want to rebuild my drive myself. A lot of special tools involved that I do not have and are very expensive to purchase. Maybe tweak your shift linkage to resolve your shifting issues before tearing the thing apart.
    Summer Fling-II
    2008 Chaparral Sunesta 264
    Summer Fling
    2003 Chaparral Sunesta 243


    • #3
      I get it if the whole thing doesn't need to be rebuilt, but what are some good maintenance items to replace while I'm in there and the engine is out? I was thinking gimbal bearing, cone clutch, and checking the bellows? Anything else in the outdrive to check?

      Suggestions for adjusting the shift linkage if that should be the only issue with delayed shifting?

      As far as the exhaust risers/manifolds, is there a way to test them out to make sure they are good and won't need replaced?


      • #4
        I would just do the normal annual maintenance: change gear oil (along with the O-rings for drain, fill and dipstick ports), lube prop splines, lube U-joints, lube gimbal bearing (replace if not smooth), and replace bellows every two years.

        Your shifting issue is probably a cable adjustment issue that you'll address when you put the drive back on. I wouldn't get internal to the drive unless there's an internal issue.

        1995 Chris Craft 21 Concept (OMC 50FAPHUE)


        • #5
          Ok thanks, I'll just do that maintenance then. The bellows are at least 3 years old, so I'm sure those are due for replacement.

          What about the risers, any easy way to check those to make sure they are still good as well when I pull them?


          • #6
            The Volvo SX bellows lasts a long time if you stored it with the drive down. The bellows is the same as on the OMC Cobra and the last one I changed lasted 11 years before I saw small cracks developing in the folds. If you pull the drive and find no water in the bellows, and there are no small cracks starting in the folds, and the rubber is not getting all stiff, then it is still good. The gimble should turn very smoothly when you turn it by hand, if you feel any roughness then replace it. If they are kept greased and there is no water intrusion, then they can last 10+ years. Mine was last changed in 2005.

            Manifolds and elbows, well you have to go by what it looks like when you take them apart. The sealing surfaces should not be eroded and pitted, if they are, you may be able to clean them up with a belt sander. The manifolds can be tested off the boat propping them up level and filling the water passage with acetone (careful, it is very flammable). Acetone has less surface tension than water and will find small cracks or rusted areas. Look in the exhaust ports that match up with the exhaust ports in the cyl head. Also there should be no rust in the cyl head exhaust ports, if so the exhaust is suspect. The elbows (many call them risers but they are really elbows) should not be clogged with flaking rust in the exhaust ports. Is this a fresh water or salt water boat?
            Heres a pic of an 11 year old bellows and what the sealing surfaces look like on a new manifold....the last pic shows what the exhaust ports should look like, no rust inside. Ignore the rust on the outside of the head, that's from the gasket holding moisture against it.
            1988 Four Winns 200 Horizon
            4.3 OMC Cobra

            98 Jeep Grand Cherokee 4.0 Selectrac
            07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

            "While air doesn't freeze....rust never sleeps"


            • #7
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              Thanks for the information! I always lower the prop down once I get home, but the boat is used, I've had it for 3 years, so not sure the maintenence it had before that.