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Contemplating custom building a 5.7 for my 2359.

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    #46
    Still havent done this build.Rick what is your take on these questions?
    1. Its around 4000 Canadian for a stock crate engine. The additional cost of custom pistons extra milling and balancing is nearly $2000. I put 100 hours a year on boat. Say$ 5000 worth of fuel.At 5 percent fuel saving thisd pay off in 8 years. Is this realistic I wonder?
    2.Also I seem to have TB5 ignition not tb4 like i thought.. Changing from a 5.0 to 5.7 I wonder if itd do the job I want. Need to get more advance I blv. Not sure if itd do this or not.

    Comment


      #47
      I bought a GM crate engine for my 2452. 350/357 HP and like it . you only get 6 months parts as they wont warranty for a boat but dollars for HP they are a good deal. Much better fuel enconomy due to the fact the engine doesnt have to work as hard. Still cruising at 4000 RPM as i carry a lot of weight. 15.3x13 Stainless 4 blade
      1996 - 2452 - repowered 350/300 HP, 600 Quick Fuel, Edelbrock, Aplha One 15.5 x 15
      1997 - 195- Repowered 4.3, Edelbrock 4 Barrel Aplha One Stainless, 19 pitch

      Comment


        #48
        .......................
        Originally posted by telstar1 View Post
        Still havent done this build.Rick what is your take on these questions?
        1. Its around 4000 Canadian for a stock crate engine. The additional cost of custom pistons extra milling and balancing is nearly $2000.
        In my opinion, here's why that particular math does not work out!

        A person would NOT be starting out with a fresh Crate Engine ($4000), only to tear it down and change pistons, balance the rotating assembly, etc.
        You would be starting out with the correct components to build one from scratch.

        A set of Q/E Pistons might run you $200/$250 compared to that of the GM F/Ts at $125 max.
        Balancing the assembly might run you an extra $200.
        The rest of the assembly is not all that different (i.e., calculate the deck height, compressed head gasket thickness, quench dimension, etc.)
        If the shop thinks that it is considerably different (to the tune of an extra $2,000)........... find a more qualified shop who knows their stuff.



        I put 100 hours a year on boat. Say$ 5000 worth of fuel.At 5 percent fuel saving thisd pay off in 8 years. Is this realistic I wonder?
        The Q/E build will not only offer a fuel savings, it will offer you a performance improvement as well in the form of "torque".

        2.Also I seem to have TB5 ignition not tb4 like i thought.. Changing from a 5.0 to 5.7 I wonder if itd do the job I want. Need to get more advance I blv. Not sure if itd do this or not.
        The non-mechanically advancing Thunderbolt distributor would be the same.
        The module would need to be changed.
        Better yet.... rid yourself of that proprietary TB ignition system altogether.




        I bought a GM crate engine for my 2452. 350/357 HP and like it .
        Most any SBC 350 that is rated at 357 HP was not designed for use in a Marine application.

        you only get 6 months parts as they wont warranty for a boat
        I'm surprised that you even got a warranty if the company knew that the engine would be used in a Marine application.

        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


          #49
          oops i screwed up large time the difference is $1018. The pistons KB142 are $583. Thats Canadian remember. $325 for balancing. $110 to mock up block for deck height etc.Thanks for getting my attention on that Rick. One price was taxes in the other one taxes out.I didnt notice.
          Anyhow would you care to take a wild guess as to the fuel consumption difference between stock and the quench version?The extra torque would be nice but its not a huge deal to me. If she gets up on plane in a reasonable time Im happy more or less.The rebuild fellow seemed knowledgeable on what Im wanting. He was however skeptical that id ever recoup my $1018 .Also to get the compression ratio right with available pistons they have to plane the block down(or use thin gaskets which is not exciting to me.)After planing I guess Im committed, if I dont like the engine theres no going back to standard.But hey Im going to love this thing right?

          Comment


            #50
            ..................
            Originally posted by telstar1 View Post
            oops i screwed up large time the difference is $1018. The pistons KB142 are $583. Thats Canadian remember. $325 for balancing. $110 to mock up block for deck height etc.Thanks for getting my attention on that Rick. One price was taxes in the other one taxes out.I didnt notice.

            Anyhow would you care to take a wild guess as to the fuel consumption difference between stock and the quench version?
            In all of my years working on the SBCs (starting in the mid 60s), in both Auto and Marine, have never used nor built a SBC using the GM Full Dished pistons. So, I am not able to share any personal data as a comparison.

            However, we do have a member who once posted his data. I'll see if I can get him to respond to your question.



            The extra torque would be nice but its not a huge deal to me.
            Torque is what we are after.... much more so than HP alone.
            Torque requires a good LPCP.
            A good LPCP is 12* to 14* ATDC.
            The GM FD piston cannot possibly create a decent LPCP.



            If she gets up on plane in a reasonable time Im happy more or less.
            Understood.

            The rebuild fellow seemed knowledgeable on what Im wanting. He was however skeptical that id ever recoup my $1018 .
            If this is about re-cooperating your cost, then I think that you had better stick with the GM build.
            For me, it would be more about eliminating detonation potential, more Torque and greater engine longevity.

            Also to get the compression ratio right with available pistons they have to plane the block down(or use thin gaskets ...............)
            1.....What is the deck height now?

            2.....What Static Compression Ratio is this machinist shooting for?

            3.....What quench dimension is this machinist targeting?

            4.....Does this machinist understand:
            a....... that both the GM Full Dished pistons, and any of the Q/E style pistons, incorporate a dished area?
            b....... and that we vary the dish volume (along with several other dimensions) to acquire the desired S C/R?



            After planing I guess Im committed, if I dont like the engine theres no going back to standard.But hey Im going to love this thing right?
            Your questions now have me a bit confused!
            Are you, or are you NOT, building a Q/E SBC?

            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


              #51
              Thanks Rick for your as usual well thought out reply.Re my objectives well i have enough torque i dont get detonation and im repacing a 19 year old std engine that still runs well but has reduced compression and increased fuel consumption(so longevity not a problem either)Im still however attracted to the idea of the custom build.
              Re the engine specs with the only pistons we could find that came even close to our objective (KB142) we need 0 deck height with a .038 gasket.for 9.3 C/R.and .038 quench.62cc heads. Shop to machine block and heads to achieve these results.There didnt seem to be any other pistons available that would make this all work.
              The last question was just reflecting on the fact that once one gets started on the qe build theres no going back to standard. Ignore this I guess.
              Im still a bit fuzzy on the ignition thing. I m under the impression the tb5 gives me superior idling ie fishing speed due to some wizardry i dont understand. Kind of like that. But there appear to be 3 module choices and I dont know which one I need(or what I have for that matter Ill have to look for a number)

              Comment


                #52
                Not familiar with the TB 5 module choices myself. Can you post docs on the 3 different modules you’ve discovered? I’d like to educate myself🤔
                Dave
                Edmonds, WA
                "THE FIX"
                '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
                (.030 over-Vortec top end-part closed cooled)
                The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                Misc. projects thread
                https://www.baylinerownersclub.org/f...56-gctid789773

                Comment


                  #53
                  After posting i did a bit more research. Seems there are 4 modules :861459T02 for 5.0 with Alpha;861460t02 for(ithink)5.0 with bravo;861253t02 for 5.7 with alpha ;and 861254 for 5.7 with bravo.Got this verbally from a Mercruiser parts guy. I think I got it right.No idea what difference is though id like to know.The 5.7 units go with a knock sensor. Anyhow the tb5 thing is looking less attractive to me. Its around $2000 Canadian for a module and knock stuff. Hoping Rick will chip in with just what I need in an aftermarket setup. I believe there are options for different advance curves not exactly sure which one I need.

                  Comment


                  #54
                  I was curious to know what the different advance curves might be for the TB5 modules. I thought all TB5’s used the knock sensor but I could be wrong on that.
                  There are aftermarket versions available for far less.

                  https://www.wholesalemarine.com/sier...onversion-kit/

                  https://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-119.html
                  Dave
                  Edmonds, WA
                  "THE FIX"
                  '93 2556 5.7 Bravo II 2.0:1 18 1/4x19 P
                  (.030 over-Vortec top end-part closed cooled)
                  The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
                  Misc. projects thread
                  https://www.baylinerownersclub.org/f...56-gctid789773

                  Comment


                    #55
                    ......
                    Originally posted by telstar1 View Post
                    Thanks Rick for your as usual well thought out reply.
                    You are most welcome!

                    Re my objectives well i have enough torque i dont get detonation
                    Your engine may not undergo detonation due to the Merc ignition system holding back on the spark lead.
                    Not BASE advance, we're talking about the Progressive and the TA (total advance).


                    and im repacing a 19 year old std engine that still runs well but has reduced compression and increased fuel consumption (so longevity not a problem either) Im still however attracted to the idea of the custom build.
                    Re the engine specs with the only pistons we could find that came even close to our objective (KB142) we need 0 deck height with a .038 gasket.for 9.3 C/R.and .038 quench. 62cc heads.

                    OK.... the Quench dimension is a result of:
                    .... piston deck height..... I.E., the distance that the piston sits below the top of the cylinder deck.
                    .... compressed head gasket thickness...... I.E., the dimension of the head gasket when fully compressed by the cylinder head bolts.
                    The total of those two = the "quench dimension" ..... but ONLY if the piston deck offers a Quench surface!

                    (the GM Full Dished piston cannot possibly create a Quench Effect! )



                    But let's get back on topic with the Q/E style pistons:
                    Let's say that the piston deck height is .016" (in other words, the piston @ TDC is .016" from reaching the top of the cylinder).
                    .038" is a suggested quench dimension for a SBC with a 3.480" stroke. In other words, a 5.7L SBC.
                    .016" from .038" = .022"
                    .022" would be the targeted compressed head gasket thickness.

                    Now let's say that the piston deck height is only .010"
                    .010" from .038" = .028"
                    .028" would be the targeted compressed head gasket thickness.


                    As for the Static C/R, that is a result of:
                    ..... cylinder head combustion chamber volume.
                    ..... piston dished area volume.
                    ..... quench dimension.

                    You can plug your numbers into one of the better "on line" static compression ratio calculators.
                    Your cylinder number will be 8
                    Your bore will be 4.030" (first over, I assume)
                    Your stroke will be 3.480"
                    Your cylinder head chamber volume will be 62cc according to your info.
                    You will need to know what the piston deck height will be.

                    Vary the piston dish volume until you come up with a satisfactory Static Compression Ratio.


                    Keep in mind that the good tight Q dimension allows for a bit more on the S C/R.
                    In other words, you may be able to exceed your 9.3:1



                    Shop to machine block and heads to achieve these results.There didn't seem to be any other pistons available that would make this all work.
                    Perhaps this shop is not looking quite hard enough.


                    The last question was just reflecting on the fact that once one gets started on the Q/E build there's no going back to standard.
                    Not necessarily true.... and it begs the question, why would you want to go back to a GM style F/D piston?

                    Ignore this I guess.
                    Im still a bit fuzzy on the ignition thing. I m under the impression the tb5 gives me superior idling ie fishing speed due to some wizardry i dont understand. Kind of like that. But there appear to be 3 module choices and I dont know which one I need(or what I have for that matter Ill have to look for a number)
                    I'm not a fan of the EST systems.
                    However, Merc does offer an array of modules that will give you a more aggressive advance curve and TA.

                    Many of the GM built SBC Marine engines (full dished pistons) see approx 28* only @ 3,200 RPM.
                    An advance like that places the LPCP at let's say 17* to 19* ATDC, of which is rather lazy.
                    Ideal LPCP is near 12* to 14* ATDC.


                    After posting i did a bit more research. Seems there are 4 modules :861459T02 for 5.0 with Alpha;861460t02 for (i think) 5.0 with bravo;861253t02 for 5.7 with alpha ;and 861254 for 5.7 with bravo.Got this verbally from a Mercruiser parts guy. I think I got it right. No idea what difference is though id like to know.The 5.7 units go with a knock sensor. Anyhow the tb5 thing is looking less attractive to me. Its around $2000 Canadian for a module and knock stuff. Hoping Rick will chip in with just what I need in an aftermarket setup. I believe there are options for different advance curves not exactly sure which one I need.

                    Options:

                    ...... a mechanically advancing system whereby the curve and TA can be adjusted.
                    ...... a non-Merc EST that is more easily program-able.
                    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


                      #56
                      Re the pistons deck height etc where I got to was IFI want anywhere near .038 squish and gasket is (say).038 compressed,the only way to achieve that is increase piston pin height dimension orshave the block...am I right? The only piston I could find with right or even close CCS and the right shape was the kb142 which has 1.561 pin height.
                      te distributor.if I get an aftermarket mechanical advance dist
                      I seem to be looking at a Sierra 18 5494 2 which replaces Mallory ylm624av which is nla.are there others? Not clear to me if there are advance option kits I asked the question online. Rick I'm hoping you can help zero in on this.


                      ​​​​
                      ​​​​​

                      Comment


                        #57
                        Telstar, in your original post you stated your cruise fuel burn is 42 lph which equates to around 11 GPH. Unless you are able to use your boat far more than the average user I bet you don’t spend more than 50-75 hrs at CRUISE per year. For that amount of time if your fuel burn was 2 gph, 8-10 lph more or less than the present 42 lph I seriously doubt that would make or break the bank. I’d build that engine to develop as much power/torque the drive will allow and enjoy the performance increase. Heck, with the more powerful engine you might even see the same or a slight reduction in fuel flow!
                        Jim Gandee
                        1989 3888
                        Hino 175's
                        Fire Escape
                        [email protected]

                        Comment


                          #58
                          I just found a post from a guy who has a 89 Trophy, originally it had a 3.0L that was way underpowered. He got a Lt engine out of an early 2000's Chevy Tahoe, remapped the ecm, lowered the max rpm to about 5000 and uses an Alpha One outdrive. Closed cooling system so no seawater in engine. He is very happy with it.

                          Comment


                            #59
                            Sorry, LS-3 engine. 300 hp with an Alpha drive. Not sure why but these engines not only power Corvettes and SUV's, there is enormous amount of people using these engines to re-power rear-wheel drive cars. Co-worker put one in a Lexus 250.
                            If interested I can try to find the link back of the project with the Trophy, very detailed discription.

                            Comment


                              #60
                              Originally posted by telstar1 View Post
                              1....... Re the pistons deck height etc where I got to was IFI want anywhere near .038 squish and gasket is (say).038 compressed,the only way to achieve that is increase piston pin height dimension orshave the block...am I right?



                              2..... The only piston I could find with right or even close CCS and the right shape was the kb142 which has 1.561 pin height.


                              3..... te distributor. if I get an aftermarket mechanical advance dist
                              I seem to be looking at a Sierra 18 5494 2 which replaces Mallory ylm624av which is nla.

                              4..... are there others?

                              5..... Not clear to me if there are advance option kits I asked the question online. Rick I'm hoping you can help zero in on this.


                              1...... I would start with your cylinder block. Have the shop clean, check and prep it for boring first over.
                              At that point they can check the cylinder deck height.
                              A SBC 5.7L should be at 9.025" from the center of the crankshaft to the top of the cylinder block .
                              If this surface needs to be trued, the deck height will change.


                              2..... Once that has been determined, you should be able to order pistons of the correct wrist pin to deck height height.
                              If this shop is not capable of doing that, perhaps find one who is.

                              Click image for larger version  Name:	Quench and Squish area explained 5 jpg.jpg Views:	1 Size:	259.8 KB ID:	559871



                              3..... Yes, and what a shame. The YLM has been replaced with the YLU, of which is photo-eye triggering.
                              The YLM is VR (variable reluctor) and is a great triggering system.
                              It is all magnetic, using a highly precision reluctor wheel and pick-up sensor.
                              There has been NO reported errors with the VR.

                              I would steer clear of any system that uses the Hall Effect such as with the Pertronix units.
                              Reported errors range from 1 to 1.5 degrees at the distributor, of which equals 2 to 3 degrees at the crankshaft.


                              4..... Most have gone to photo-eye.


                              5...... With either of the mechanically advancing Mallory units, the advance curve can be altered as well as the advance limit.




                              Everything that we do to improve performance.... (I.E., camshaft profile, cylinder head intake runners, piston profile, fuel delivery system, ignition system, exhaust system, etc,) all boils down to how well the combustion process occurs.

                              The goal is to produce Peak Cylinder Pressure (aka LPCP..... which represents the Maximum expansion of the fuel/air "burn") at/near 12* or 14* After Top Dead Center, during the time at which the piston/connecting rods have their greatest leverage advantage over the crankshaft.
                              This equals TORQUE!





                              By the way, regarding everything that I am trying to help you with.... all of this should be easily explained to you by your machine shop owner. In fact, that person should know much more about this type of SBC build than I do!

                              If you sense that this person is not quite understanding this type of build, nor is capable of this type of build, you may want to find another shop.
                              No offense.... just being realistic 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

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