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Review: Mercruiser 4.5L V6 vs 4.3L V6 / Bayliner 215 Deckboat-gctid618559

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    "Four Pyrates" post=620037 wrote:
    I never said it was new tech or even the best tech. Just reliable. I know it is old but until it fails, what do you do? Merc has always rested on its "laurels". When Evinrude built a 10 HP saildrive (25" shaft), Merc said 20 was enough. And on and on. If Merc wants to impress anyone, then build something that is modern, quieter, and more efficient. Simple as that. So far, the outdrives aren't all that much different over the years. The outboards are better but I don't use them.
    That's my point. It's time for Merc to get off the bleachers and make a reliable AND up to date drive. Or, if it's too expensive, kill the Alpha entirely and drop the price of the Bravo 1.
    Matt Train
    BOC Site Team
    Chicagoland, IL


      "Four Pyrates" post=620025 wrote:
      "RGrew176" post=619994 wrote:

      I can't say it any better than Matt said right below your post. The Alpha is old tech and it is outdated when compared to any other drive system currently on the market..
      Maybe someone will figure out how to improve the Alpha drive. After 20 years with zero issues, I wouldn't change one just to quiet it down a bit. We have Simrock outdrive coolers on all three and those work very well. I'm convinced they help keep the wear and tear down to a minimum. One thing for sure is I don't want any outboard engines no matter how smooth they run. The lines of a good boat are ruined by this hump in the back and they cost way too much for horsepower produced. I hope the new I/O engines will answer the call and be the workhorse. The beat goes on!
      Not if they can hide em nicely :silly: Searay is doing it already...[/IMG][/IMG]
      Joon, Kathy, Jaden & Tristan
      Uniflite 42 AC, DD 671N
      93 3058 sold
      92 2855 (day boat)
      91 Fourwinns 205 (lake boat)
      Longbranch WA
      Life is Good


        Sea Ray is absolutely KILLING IT on new product these days, and that 370 Venture is pretty much the coolest express cruiser I have ever seen. I would love to wheel around a 370 Venture on a press event.

        Brilliant, out of the box thinking all over the model range. Their new SPX models are really cool looking too.
        Matt Train
        BOC Site Team
        Chicagoland, IL


          Hey Ruff,

          Leave it to SR to sneak in a new/old idea. nice photos.


            FYI: The 6.2 is a 5.7 Block stroked, not bored. The long stroke gives it low end torque.

            I agree about doing some R&D on a lot of marine stuff. Like making a small boat horn which lasts more than 3 years in salt atmosphere.

            We had a Nissan V6, 3.5 ltrs which was putting out 265 HP in street trim. Since marine engine are not as much pollution rated, they should get 300 out of it in a boat.

            We now have a 2.5 L Toyota with a 170 HP 4 banger. The 3 ltr M/C boat engine is 130 HP and is a half ltr bigger?

            The alpha drive is an improvement over the original "1" drive from the 1960s. About 1985, they had a lot of failures in it, when mated with 5.7 4 BBL engines (260 HP) using in 26-28' cruisers. M/C beefed up the prop shaft and lower gears, and made a much heavier duty vertical shaft. The retained the Outboard motor style "dog clutch" and still do. That's why they are noisier than Volvo.

            Then in the mid 90s, they went to Alpha generation II, however, still the O/B clutch/gears.

            The bravo is a meld of the alpha and Volvo drives. When it was designed, Volvos patents of the cone clutch and water pump on engine expired, so mercy did not have to pay royalties to them. Additionally, at the same time Merc patents on the hydraulic power trim/tilt and the thru-hub exhaust expired, so Volvo pick up on those.

            And OMC had their abortion of shifting being electric solenoids and springs.

            So, the future is R&D. However, with the boating industry in its slump, I doubt that money will be appropriated unless the auto industry just plain stops making engines...

            They also tried making a big bore 4 banger in the mid-70s. It was a strong running engine (when it would run) and fuel stingy which was what it was designed for. However, they were plagued with problems.
            Captharv 2001 2452
            "When the draft of your boat exceeds the depth of water, you are aground"


              I think we will see a stern drive resurgence here in the coming years thanks to this technological cross roads.

              Merc is going their own way with proprietary engines, Volvo is going to continue marinizing new GM tech. I am hearing growing rumblings that there may be a case to redesign the Alpha, and as alluded to, its WAY overdue.

              So we shall see. But right now, there's a strong case to be made for going OB over lower level Merc stern drives.
              Matt Train
              BOC Site Team
              Chicagoland, IL


                Some of the OB motors that can compete with that 4.5 will set you back $20k


                  It would be interesting to see how these motors are faring now that they have been on the market a few years. I took a look at some parts diagrams to see if there is any similarity between the old GM 4.3 and the Merc 4.5. What I saw, was that the short block assembly looks IDENTICAL. Of course it may not really be so, but the similarity was striking. The cyl heads look like they were completely re-designed. It makes me wonder if Merc, bought the tooling for the 4.3 long block from GM, or entered into some kind of licensing agreement as I think the GM 4.3 is still being built for industrial use and the repower market for older boats. Its good that they improved on the original, if that is what happened.....

         <-----GM original short block....

         <------Mercruiser 4.5 short block

                  see any differences?
                  First of all, the complaint about the rough running 4.3s was partly due to the 90* cyl orientation that was partially amerliorated by adding a balance shaft. If Merc designed their own 'new' engine why did they then not change the cyl orientation to 60* for the V6 which would make the balance shaft unnecessary...…..looks like they want to use this tooling for future V8s, when GM stops making what they can maybe preparing for assembly line commonality when the time comes....
                  I hear it costs approx. $5800 to buy one of these new Merc long blocks, so I hope that those single point drain systems really work. I'm not against new designs and refinement but in this day an age, inboards and I/Os NEED TO HAVE CLOSED COOLING STANDARD. No one likes the rush to drain the damn things every fall and those single point drains systems, stop draining well after a few years. If they want to draw people away from outboards, that is a needed standard item. Just make the heat exchanger easy to drain.

                  About the Alpha, I agree, my 30 year old Cobra is more refined shifts better and easier to maintain (impeller is 15 min job, bellows easier to change, no shift bellow outside the boat that can leak and sink the boat). As common and cheap as they are, with parts everywhere, I would not want even a used boat with one.
                  88 Four Winns 200 Horizon 4.3 OMC
                  98 Jeep Grand Cherokee 4.0/Selectrac
                  07 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

                  Long Island Sound Region


                    I had Alpha drive in first 2 boats...both matched up with the 5.7. I will say I never had issue with second Alpha drive, which I ran for 10 years. This first one blew gears thru the lower unit housing but could have been due to prior owner neglect.

                    My current boat is 10 years old with the Volvo Penta drive....the shifting is 100 times smoother with no clunking and th s way quieter. I have the single prop drive and don't want the duo prop.

                    the biggest tell is the VP drive runs cooler and no driver shower is recommended. Long story short...tge Alpha is a good unit, but they can make a far advanced drive I'm sure.

                    Not having the impeller in the drive is also a big plus for the maintenance of the Penta. But all isn't rosy...the tilt trim on the penta has had issues...hopefully it passes me by.

                    2008 H210SS Four Winns
                    Volvo Penta 5.7 GISX
                    Prior: 1997 2050SS Bayliner
                    Brad / Texas Gulf Coast


                      Well as far as the impeller, OMC had the better idea there, the easiest to replace ever impeller. It is a 15 min job, you remove the cover on the upper gear housing (3 bolts) impeller housing (3 bolts) and replace. No removing lower unit (Alpha) or rear seats (Bravo, Volvo). Click image for larger version

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                      88 Four Winns 200 Horizon 4.3 OMC
                      98 Jeep Grand Cherokee 4.0/Selectrac
                      07 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

                      Long Island Sound Region