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1985 2750 ciera sunbridge-gctid376499

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    1985 2750 ciera sunbridge-gctid376499

    OK, here I am again,History is, I bought this 1985 2750 back in 09', for 3500. needed alot of work, but the hull was sound and the motor ran good. It has a 5.7omc with a stringer 800. I went into it blind, as this is my first big boat, and didnt do alot of research on it. I put alot of elbow grease into it, and wound up here 3 years later with about 6k in it.Present, I launched 2 weeks ago, other than fuel filters clogging on me, all went well. took her out 3 times since then. all has been well.Then, sat night, was looking for a bay to pull into and anchor for the night, and the engine started cutting out. I looked down and oil pressue was only about 15psi. before I could cut it off, I heard what I know was a knock from the lower end. The next morning I got a tow into the closest marina, put her on the trailer, and shes in the drive way again.I am torn on what to do. I like the boat. she has a really good lay out, plenty of room for the family, and overall looks really good. I dont really want to invest more money in her than I can get out of her. I thought about just pulling the motor out, slapping a rebuild kit in her (if the block is ok), head job, and trying that out. Everyone is telling me that I would be better off doing an engine swap, but that would run me into alot of money. selling her is an option, but if I buy another, I may be running into the same issues on someting else.Performance on the present motor was ok, though I think a little lacking. wot was about 4100, top speed around 28mph or so. I planed her off, and ran most of the time at 33 to 3400 at about 21-22mph. seems a little sluggish though.Any opions would be appreciated.

    [img]/media/kunena/attachments/vb/679940=27071-03.jpg[/img]

    #2
    First of all, you need to come to terms that boats are never investments in terms of a finacial recovery or gain. They just simply do not fit into this category. Many of us are what we call "Up-Side-Down" in our older boats, and with no thoughts of ever recoverying our initial costs.

    We use them and we enjoy the benefits of having all of our upgrades, etc.

    A new correctly build 5.7L engine is not entirely out of the question. This involves a bit more than a standard automotive build in order to do correctly.

    The boat itself looks to be very clean and nice, and is very worthy of a new engine.

    However, the main draw-back of this boat is the OMC Stringer Drive.

    Looks like you've a got a decision to make here!

    .
    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


      #3
      yeah, i havent heard anything good about the stringer, but it seems to run good. I would change it out, but I know that it takes extensive work on the transum, and im not up for that at this point. As long as it holds in there, i will probably run it. I do have a machine shop at my disposal, so I wont incur any expenses on that part, just the cost of parts. I am leaning toward just pulling the motor and rebuilding. i have seen complete rebuild kits on ebay for 400 or so. I am in the green on this boat right now, as in terms of resale value vs what I have in it, and I dont want to go crazy with it, as I dont know if i want to keep the boat long term. I would like to have something with a wider beam. It is nice that it is trailerable, but I plan on keeping it at the marina anyhow.

      Comment


        #4
        Well, you seem to have a good attitude about it, and that's great!

        When/you rebuild.... and since this a 27 footer....., read some of our threads on the 5.7 and 6.2 overhauls regarding piston selections!

        .
        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


          #5
          the only difference in a marine, and a car/truck long block is a marine ground cam,brass freeze plugs, and marine head gaskets..the plugs and gasket are only different to handle being in water all the time..the big differences are the bolt on accessorys that you would reuse.. good luck with the boat.

          Comment


            #6
            vicjunkie wrote:
            ....... I do have a machine shop at my disposal, so I wont incur any expenses on that part, just the cost of parts. I am leaning toward just pulling the motor and rebuilding. i have seen complete rebuild kits on ebay for 400 or so. I am in the green on this boat right now, as in terms of resale value vs what I have in it, and I dont want to go crazy with it, .........
            Well, again.... I think that you need to forget the idea that you will re-coop your expenses. It just doesn't work that way with boat ownership. At least not often!

            You made a purchase, and perhaps one without researching a bit more extensively.

            The boat itself looks to be in very good condition. That alone is worth something.

            I'd personally rather have an engine issue, than to have extensive hull issues regarding transom/stringers, fiberglass or gel coat issues, electrical, plumbing, water leaks, window frames, and so on.

            An engine replacement may be more costly, but when all of the horses are back in the barn, you'll know just what you have.

            If this unexpected expense puts you $XXXX over original budget, run it for a year or two.

            Divide the over-budget amount by the number of months usage ..... and there's your monthly cost of your alleged error.

            Looking at the numbers will only hurt for a short while!

            j1mmy wrote:
            the only difference in a marine, and a car/truck long block is a marine ground cam,brass freeze plugs, and marine head gaskets..the plugs and gasket are only different to handle being in water all the time.. ..............
            That is true if you don't mind the run-of-mill GM Marine version SBC. When we are over-hauling one, it's silly to go back together with the GM style dished pistons. There are better alternatives, and ones that don't break the bank.
            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


              #7
              I am looking at a grumpys total rebuild kit. it comes with the following

              Type of Part Sizes Available Notes

              PISTONS STD, .020", .030", .040", .060", .080" Dish Top 0.080" Deep, 1.540" CH

              PISTON RINGS STD, .020", .030", .040", .060", .080" Cast Rings, 5/64" / 5/64" / 3/16", Deep Oil Ring

              ROD BEARINGS STD, .001", .010", .020", .030", .040", .050"

              MAIN BEARINGS STD, .001", .010", .020", .030", .040"

              CAM BEARINGS

              FULL GASKET SET Standard Rotation, With 1 Piece Rear Main Seal, Center Valve Cover Bolts and 1 Piece Oil Pan Gasket, Does Not Include Late Model Vortec Intake Gaskets

              TIMING SET 3 Piece Double Roller Set

              OIL PUMP High Pressure Pump With 5/8" Inlet Hole

              EXPANSION PLUGS Brass Plugs

              what do you guys think. what are the other options on the pistons that Im gonna see a real difference in. Of course I will proboably have to go with oversized pistons, bore the block, grind the crank, and get the valves and seats ground on the heads. I will go through the whole thing and make sure everything is ok. any more suggestions. I would like to give my bilge a good cleaning and fresh coat of paint while the engine is out.

              Comment


                #8
                If this kit is from Grumpy's Garage or GrumpyVette, this will very likely be for automotive. Grumpy's articles are primarily tailored towards automotive builds.

                I have no idea what the kit includes. Perhaps you could post a link to the kit, or post a few photos of it.

                If you want to read good information, read what Dennis Moore has to say in his Small Block Chevy Marine Performance book.

                Here is Andrew1's fairly current BOC thread regarding a SBC over-haul. You'll see several other links to similar threads.

                http://www.baylinerownersclub.org/fo...lvo-rebuilt-or

                At the same time, Apexaro1 has a thread regarding cylinder head replacement, and it touches on pistons as well.

                http://www.baylinerownersclub.org/fo...eplacing-heads

                You could also give this a quick read.

                http://www.marineengine.com/boat-for...V8-engine-swap
                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


                  #9
                  here is the link on ebay to the kit i am looking at. it says it is a marine kit.

                  http://www.ebay.com/itm/1985-1995-MA...41c955&vxp=mtr

                  Comment


                    #10
                    or this one has the cam and lifters with it. I am not looking for high performance, just more reliability. It seemed to be sluggish getting on plane before, but I belive the internals of the motor havent been touched sinced 85', and there isnt any telling how many hp I was really pushing. I have no idea how many hours are on this engine. I will be installling a hour meter.

                    http://www.ebay.com/itm/GM-350-5-7-C...299b77&vxp=mtr

                    Comment


                      #11
                      This has little to do with the condition of your engine currently. I'm just going to post based on what I see, and what you've written. You bought the boat to fix up, and it looks like you've done a top notch job. I think the hull is well worth the cost of rebuilding the engine. If the outdrive was good enough for a stock engine it should be up to the task of a rebuild.

                      The engine deal is a shame, but I think you could do it right with any of the rebuild 'kits' out there. Since you are going to have to machine the crank it sounds like, I would go ahead and bore the block, and do the deck too. Marine engines have a habit of getting gunk around the head gasket and etching away at the block or head. Once you get it all apart, you can order the specific kit with the oversize bearings and pistons and rings. I would suggest replacing the cam and lifters just because you don't want to put old parts in a newly built engine. The cam is likely to have some spalling anyway due to sitting for so long between operations.

                      Add a decent valve job, and I think with your DIY skills you will have an engine that is worthy of the hull, and you can enjoy it in comfort for many, many years. Don't forget that this engine is a split rear seal. Don't let the head shop 'swap' your heads. You know you have good heads, and there is no way I would allow an exchange for something unknown. Good luck.

                      Comment


                        #12
                        Vic, on a 26 year old boat... we do not know what a previous owner may have done or changed.... even though you say it looks like it's not been touched.

                        We don't know if they replaced the cylinder heads at one time, nor if the lower end or block was replaced, nor do we know which castings would have been used.... whether replaced or not. We don't even yet know if this is a pre-1986 engine, or a post-1986 engine, although it should be a 1985 w/ the 2 pc rear main seal affair as docmirror mentioned.

                        So..... before you do anything, I'd recommend that you pull the engine apart, identify the casting numbers, run checks on these casting numbers, and see where you're at.

                        Not all casting numbers are suitable for Marine use.

                        Examples:

                        Some blocks made out of country contain a lessor nickel content, and some cylinder heads are light castings.

                        The light casting pre-Vortec heads are typically noted by the multiple scallops near the short bolt areas (see image at botton of page).

                        There is also an array of cylinder head combustion chamber volumes.

                        We'll commonly see the 64cc and 76cc chamber heads being used for the Marine SBC.

                        Because of this, we can't arbitrarily choose a piston until we know which chambers we have..... including the full dished pistons!

                        We'll often see pistons being advertised with a compression ratio shown..... but no mention of which chambers this applies to. rod

                        The first set of pistons that you link to (GrumpysPerformance) are an unusual rendition of a full dished piston. Not typically used with the SBC.

                        This style piston can not create a quench or squish within the chamber, and is one that I would recommend that you avoid.

                        If you will read Andrew1's thread, alternate piston selections are discussed, and it may answer any questions that you might have as to why the quench is important, and that the quench is not necessarily a High Performance upgrade, but rather a better way to avoid marine load detonation and make better low end torque.



                        His listing shows a dish volume of 1.540" which converts to 25.2360cc.

                        If you go to Sick's Static Compression Ration Calculator using 25.2360cc with 64cc chamber heads, you will see a S C/R of 8.5197:1.

                        If use 25.2360cc with 76cc chamber heads, you will see a S C/R of 7.6898:1.

                        Obviously that piston with a 76cc chamber cylinder head is not going to work.

                        The Enginetech P1505(8)060B set is also a full dished piston.





                        So even if you were to use the full dished style piston, you'll need to know the chamber size of your cylinder heads, as we have a Static C/R range that we must stay within.

                        Not all piston deck dished volumes are equal.

                        FYI..... the original SBC 265 ci engine was designed with a flat top piston that gave this engine a Quench Style combustion chamber.

                        The following 283, 327 and early 350 also used this design.

                        It wasn't until emission control standards of the early 70's caused GM to produce this full dished piston that we still see today in many of these SBC engines.

                        We've become so accustomed to seeing and using this piston, that we rarely question it any more! :sorrow:

                        In some 45 years of working on and building the SBC (whether auto or marine), I have never used the full dished piston, nor will I.

                        It just doesn't perform as well. But they are inexpensive and one p/n fits all 8 cylinders.

                        The cost to do a quench piston is not all that much more in the over-all scope of things.

                        In the 5.7L SBC (3.480" stroke):
                        • With the 76cc chamber cylinder heads, the Flat Top piston renders a "quench" and a nearly perfect C/R. These are very inexpensive pistons.
                        • With the 64cc chamber cylinder heads, in order to create a "quench", the piston must be a D-dish, Low Compression Quench, or a Reverse Dome style to obtain the correct C/R. These are perhaps as little as $150 more.... perhaps even less depending on which manufacturer you go with.




                        The benefits are well worth it, IMO.

                        Edit:

                        Vic, I'd be willing to bet my nickel to your doughnut, that half of these guys who speak to their machine shops (about a SBC quench build), are talked out of it simply because many of these shops (not all) are not fully up to speed on the quench principle, and/or the differences between automotive loads -vs- marine engine load detonation potential.

                        Most of these shops do 85-90% more automotive work, than they do marine work.

                        In post #10 you mention that you're not looking for High Performance, and I understand that, and I agree.

                        Understand that the Quench is not necessarily a High Performance build technique, in as much as it is for low end torque, and a darn good fight against detonation potential.

                        Nothing to the build needs to be altered.

                        The assembly procedure is identical to that of a non-quench build (minus two piston part numbers and different connecting rod assembly).

                        Only the piston selection, deck height dimenstion and compressed head gasket thickness requires a little more attention.

                        .

                        Attached files [img]/media/kunena/attachments/vb/680611=27174-Light casting 350-heads 2.jpg[/img]
                        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


                          #13
                          Thanks a million for all the input, I am planning on starting on the tear out next weekend. I will keep you guys posted on what I find, and what I go with.

                          Comment


                            #14
                            Ok, just to keep everyone updated, I finally got the engine out of the boat, and tore into it. Looks like the engine was detonating. dont know if it was from running lean, or a timing issue. good news, the crank is ok. I also found a crack in the block, due to not being winterized right. I would say the previous owner knew about this. I will keep you guys updated on my progress as i go.

                            Comment


                              #15
                              Please post photos of the pistons suspect of having undergone detonation damage.
                              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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