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    SBC- Q-Effect

    I almost attached this to a thread (Will this engine work) but decided to start a new thread. I have read many threads on SBC and am not going to build my own but would like to purchase from MM. I believe that Bounty thinks that they do good work but the piston and head gaskets and ????need to be changed.

    A little about myself and what i'm doing.

    I have what Bayliner calls a 1986 2460 trophy with a 305 and VP 280. I have removed the motor/ outdrive and will be cutting the floor to remove the gas tank. I hope that I can refurbish the fuel tank once out but time will tell. I am NOT a Mechanic, I only turn bolts. I have spent many hours on a 19' Glasply- new transom, ok lets say from the chines up have been reglassed. Many hours of fairing.

    I will be putting a 350 and adding (hopefully) a VP280 DP with trim.

    I have read that MM will Build a Q-effect SBC but what do I need to know and talk to, so its built right or is there better idea. I live on Camano Island so Bellingham and Everett are both close if there is a trusted shop. Im not rolling in dough but don't what to go cheap either. I believe a well built SBC will in time save me money.

    Thank you in advance.
    North Puget Sound/Camano Island
    1985 2460 Trophy
    VP280/305 Changing to 280/DP-350

    #2
    Don't think MM will substitute the piston anymore, Rick will correct me if I'm wrong. You say your not a mechanic so I'd suggest having a Vortec marine engine built by a local shop or maybe one from summit that's backed with a warranty.

    If I were going to the trouble of pulling out a questionable fuel tank I'd plan on replacing it with new along with all related hoses etc.
    Dave
    Edmonds, WA
    "THE FIX"
    '93 2556
    Carbureted 383 Vortec-Bravo II 2.0:1 18 1/4x19 P

    The rebuild of my 2556 https://www.baylinerownersclub.org/f...76?view=thread
    Misc. projects thread
    https://www.baylinerownersclub.org/f...56-gctid789773

    Comment


      #3
      In addition to building a Q-factor engine you will need to know how to tune the ignition advance to get the benefit of it. IMO 95% of the people out there will not notice the difference over the operating band the engine will spend most of its time at. With that said the cost of getting one built vs just an off the shelf marine engine is basically the same but you do need to find a shop that can build a marine q-factor engine and has a good reputation.
      1997 Maxum 2400 SCR 5.7LX Bravo II

      Mike

      Comment


        #4
        "builderdude" post=828979 wrote:
        Don't think MM will substitute the piston anymore, Rick will correct me if I'm wrong. You say your not a mechanic so I'd suggest having a Vortec marine engine built by a local shop or maybe one from summit that's backed with a warranty.

        .
        [color]blue wrote:
        Therein lyes the problem.Everything I've read tells me to be cautious about shops even Marine shops. Any suggestions? [/color]
        North Puget Sound/Camano Island
        1985 2460 Trophy
        VP280/305 Changing to 280/DP-350

        Comment


          #5
          I am with you WBT. It is one thing to be informed that it is better (Q factor), but that info is rather useless if you don't personally know of a reputable builder that will build it and back it. I believe what I have read, but get one where?
          Johnson Point, Olympia, WA
          1989 2855
          Horizon 6.2 and Bravo II

          Comment


            #6
            Having owned and operated a engine machine shop years ago, most if not all warranty come backs are a direct result of after installation factors. Timing, bad fuel, improper break in, wrong prop etc etc.

            I strongly suggest getting a shop that can do everything for you. From removing to reinstalling and tuning and breaking the engine in. This way if anything goes wrong it is on them. Tell them what you want, but get them to deal withe the machine shop and installation and sea trial.

            The other option is to get some advice as to what to ask for at the machine shop from Rick, myself and others on here. Then you can select a shop that seems to know what they are doing. Do the install yourself, and follow the instructions from us and the shop to a T. Most shops do not do shoddy work. A quench build is not rocket science to a machine shop that does custom work.
            Joel
            1987 3818 Hino 175
            "Knotty Girl"
            Prince Rupert B.C.

            Comment


              #7
              First of all...... I have not heard the term "Q factor" used before.

              I believe that you are asking about (and more accurately stated) is the "Q/E", of which stands for "Quench Effect", of which pertains to the combustion chamber design only.

              Without going into extreme engineering details, the dreaded GM Full Dished piston profile gives the flame front an area to hide in.

              When it does, it makes this style gasoline engine combustion chamber very "Detonation" prone.

              The FIX is to cut back on ignition advance.

              The cut back in spark lead creates a lazy LPCP. (LPP = location of peak cylinder pressure, of which should be 12 to 14 degrees ATDC)

              A lazy LPCP renders this engine short on torque.

              We want TORQUE in a Marine Engine.

              This is nothing new...... the quench effect, Detonation control and LPCP have been studied for years and years.

              And NO...... according to my sources MM will no longer build a Q/E SBC .

              What a shame!

              When you begin selecting a machine shop, and begin asking questions regarding Q/E ........ if they give you that "Deer-in- the- Head- Lights" look ........ find another shop ASAP!

              .



              Attached files

              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
                Rick a couple of things;

                Do you have a power curve that shows the difference between a Q/E and a standard GM Vortec?

                Before sending the OP down the Q/E path also inform him on how to set up the timing advance correctly as this may be to intimidating for him and failure to do it properly can result in engine damage. Yes incorrect timing on any engine can cause damage but with the ignition advance you are using is less forgiving in improper setting.
                1997 Maxum 2400 SCR 5.7LX Bravo II

                Mike

                Comment


                  #9
                  "Nauti Mike" post=829127 wrote:
                  Rick a couple of things;

                  Do you have a power curve that shows the difference between a Q/E and a standard GM Vortec?

                  Before sending the OP down the Q/E path also inform him on how to set up the timing advance correctly as this may be to intimidating for him and failure to do it properly can result in engine damage. Yes incorrect timing on any engine can cause damage but with the ignition advance you are using is less forgiving in improper setting.
                  [color]blue wrote:
                  That would be great. I do understand some simple timing. Intimidating-no, understand-somewhat, give a SxxT-yes. Numbers may not be right but a boat needs to be full in at 3000 because of consent load. I'm trying to gain knowledge, so all info is appreciated.

                  [/color]
                  North Puget Sound/Camano Island
                  1985 2460 Trophy
                  VP280/305 Changing to 280/DP-350

                  Comment


                    #10
                    "2850Bounty" post=829119 wrote:
                    [color]blue wrote:
                    First of all...... I have not heard the term "Q factor" used before.

                    I believe that you are asking about (and more accurately stated) is the "Q/E", of which stands for "Quench Effect", of which pertains to the combustion chamber design only.

                    [color]black wrote:
                    [color]black wrote:
                    Without going into extreme engineering details, the dreaded GM Full Dished piston profile gives the flame front an area to hide in.

                    When it does, it makes this style gasoline engine combustion chamber very "Detonation" prone.

                    The FIX is to cut back on ignition advance.[/color[/color]]

                    The cut back in spark lead creates a lazy LPCP. (LPP = location of peak cylinder pressure, of which should be 12 to 14 degrees ATDC)

                    A lazy LPCP renders this engine short on torque.

                    We want TORQUE in a Marine Engine.

                    This is nothing new...... the quench effect, Detonation control and LPCP have been studied for years and years.

                    When you begin selecting a machine shop, and begin asking questions regarding Q/E ........ if they give you that "Deer-in- the- Head- Lights" look ........ find another shop ASAP!

                    .[/color]]
                    [color]blue wrote:
                    OK so I changed the thread name, but its also why I'm asking for info. Everyone that sells rebuilt SBC are selling them with the piston profiles I'm not wanting to spend my money on. A local shop with my lack of understanding can BS me too. I've read all I can find on this. I believe you help Bill V from the Glasply site with his build. Would you recommend PM Bill for the shop he used? [/color]
                    North Puget Sound/Camano Island
                    1985 2460 Trophy
                    VP280/305 Changing to 280/DP-350

                    Comment


                      #11
                      A quench built engine is not that hard. It's not even rocket science. It's a matter mostly of choosing the correct piston and the correct head gasket combined with with piston deck height. Piston and cylinder head combinations can make a difference too but for the most part it's a piston with a quench area and a piston to head/deck height clearance or 35 to 45 thousandths. Most of the time if the deck height is good and you have the correct piston ( flat top or quench area piston)the quench can be adjusted solely by head gasket choice. If you are unsure about pistons a flat top piston is a safe bet but you will need the proper head chamber size to go with the piston you chose to keep the compression acceptable. With quench you can go up a little in compression without I'll effects from say a dished piston but you still cant go crazy.

                      Some racers will close the gap but in a boat you will be pushing it.

                      You can get fancy and use "D " dished piston ( not a emissions smog dished piston) but you don't need to. Usually a different type fast burn head works best with those but you don't have to do that.

                      Racers use this technology but it's not race technology. It will give you more horse power and better engine response but in a boat the benefits mostly can be significantly better fuel economy and more available torque. The extra power is just a side benefit.

                      Timing also isn't a big secret. Mostly a small block can only tolerate about 12┬░ bdc sometimes more if you change out the standard cam. ( a different discussion) even if you run stock timing you will get most of the benefits of quench. In the old days before emmisions pistons some engine specs called for 8 to 12 degrees bdc.

                      The small amount of extra money it takes to make a quench built engine will pay for its self in just one week long cruise in fuel savings.

                      If you Google quench built engine you will find some.really good articles and videos on the subject to better understand how it works how to do it and why you would want to do it.

                      http://www.superchevy.com/how-to/eng...earance-guide/

                      https://m.youtube.com/watch?v=w60eMUUWOOw
                      1989 Avanti 3450 Sunbridge
                      twin 454's
                      MV Mar-Y-Sol
                      1979 Bayliner Conquest 3150 hardtop ocean express.
                      Twin chevy 350's inboard
                      Ben- Jamin
                      spokane Washington

                      Comment


                        #12
                        Regarding Dave's post........ most any article by Jeff Smith is very worth reading.

                        Jeff is a HP automotive enthusiast..... and is not necessarily into the Marine SBC. However, when it comes to the Q/E, he knows what he's talking about.

                        The Marine SBC 5.7L can use a .038" quench dimension. (source = Dennis Moore)

                        The Marine SBC 6.2L can use a .045" quench dimension. (longer stroke)

                        The HP Auto version SBC should see a .060" quench dimension (depending on red-line rpm).

                        Regarding the YouTube video. I see a few things that might need clarification:

                        1...... the area that the man points to is a quench band, not a quench area. A quench band is extremely ineffective!

                        The actual quench area is the area that is created between the cylinder head's quench surface (the flat surface north of the wedge chamber) and the flat surface of the upper piston deck.

                        To be most effective, this piston deck area should "mirror" the cylinder head's quench surface.

                        Early SBC cylinder heads = D dished piston or a F/T piston (depending on chamber volume).

                        Vortec SBC cylinder heads = LCQ style piston.

                        2...... the piston deck height dimension should prevent the piston from being above the deck!

                        The quench dimension is determined by:

                        a.... the piston deck height

                        b.... the compressed head gasket thickness

                        Perhaps read my comments in this 2011 thread (start reading at post #7)

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

                        In most cases, we can build a Q/E SBC 5.7L for only a few dollars more than if using the F/D pistons.

                        After your parts selection has been made, contact a reputable camshaft company and give them your info. They will know what to recommend.

                        For a good hypereutectic piston that can offer a Q/E, you will need 4 part numbers. (right/left banks...... and opposing int/exh valve sequence)

                        The machine shop will fully understand the Q/E and the correct quench dimension..... if not, find another shop!

                        Nothing else regarding the build needs to change.

                        ************************

                        Hypereutectic pistons are made of an aluminum alloy which has much more silicon present than is soluble in aluminum at the operating temperature.

                        https://www.google.com/search?ei=2zX....0.sbE3dnWMnbQ


                        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
                          "2850Bounty" post=829176 wrote:
                          "Nauti Mike" post=829127 wrote:
                          Rick a couple of things;

                          Do you have a power curve that shows the difference between a Q/E and a standard GM Vortec?

                          [color]blue wrote:
                          NO I do not. However, I will suggest that most any mechanical engineer will agree that LPCP should occur at/near 12* to 14* ATDC.

                          In order to achieve a 12* or 14* LPCP, the spark lead must be a bit more aggressive.

                          In order for the spark lead to be more aggressive, a quench area must exist.

                          The GM Full Dished piston profile cannot possibly create a quench area, and with a more aggressive spark lead, Detonation will occur!

                          But let's delineate between a Quench Effect built SBC and a Vortec SBC.

                          Prior to the early 70s, all SBC engines incorporated a flat top piston, which is capable of creating a quench area (aka squish area).

                          The first SBC V-8 was the 265 cu in version and was fitted with F/T pistons. (this required two piston part numbers)

                          The High Performance Vortec engine (not intended for Marine use) also incorporated a quench area by using a quench style piston.

                          The standard Vortec version used the GM Full Dished piston....... (one part number fits all 8 bores)

                          So......... if speaking strictly Marine, there is little sense in comparing the pre-Vortec SBC to the Vortec SBC........... neither offers a Q/E! [/color]

                          Before sending the OP down the Q/E path ................

                          [color]blue wrote:
                          I believe that he is taking this path on his own...... yes/no?

                          I'll certainly help him if I can! [/color]

                          also inform him on how to set up the timing advance correctly as this may be to intimidating for him and failure to do it properly can result in engine damage. Yes incorrect timing on any engine can cause damage but with the ignition advance you are using is less forgiving in improper setting.

                          [color]blue wrote:
                          I'm not comfortable offering ignition advance numbers to people...... too much room for misinterpretation or misunderstanding, etc.

                          I am willing to suggest that the curve should be rather linear, and that the TA @ 3,200 rpm can be in the 32* range. [/color]
                          Hi Rick, thanks for responding. I do, like many others value your knowledge and inputs. Another question on the Q/E engine, with the higher compression and greater ignition advance what octane fuel is recommended?

                          It's not that I am against going to a Q/E engine I just would like to know for myself and others the costs of building and operating this engine as well as risks on set up. IMO most folks don't fully appreciate what is required to build including having the distributor curve set for this application.

                          thanks again
                          1997 Maxum 2400 SCR 5.7LX Bravo II

                          Mike

                          Comment


                            #14
                            From my understanding q/e engines allow for better temp handeling and lower the chance of detonation. So with that said depending on your overall compression ( im guessing well under 10:1) regular or mid grade should be fine. Most marine fuel is mid grade anyways.

                            As far as finding a good marine builder, google "marine engine builder (your area)" look for links that come from offshoreonly forum. Or just search that forum. Guys on that site are so engine crazy its stupid. I found 6 different recommended marine engine builders in my area from that, before i had no friggen clue as they are not really listed otherwise.

                            I could tell give you recommendations for michigan but you will pay shipping... if you cant find any though we have some rather great ones here. Sterling engines in milford are just insane with what they do. They hold speed records 202mph going down the detroit river, just blows my mind.
                            1993 formula pc 31 twin 454 bravo 2
                            1989 2655 cierra 5.7 omc cobra
                            2014 "searay" tandom trailer

                            Anchor bay clinton river
                            Michigan

                            Comment


                              #15
                              Wanted to update how things are going. After many attempts, with the help I received from you all I found a local builder. Found a 2008 low hour long block to rebuild. The block was scored to bad to be bored but the heads saved me a little money. Found a older 4 bolt main block that will get final machining when the pistons get here.

                              If anyone needs 64cc heads or a 305 long block and lives around Seattle, send me a PM. I have a total of $100 tied up in both long blocks. Not looking to get rich

                              Thanks again for the all info. Brad
                              North Puget Sound/Camano Island
                              1985 2460 Trophy
                              VP280/305 Changing to 280/DP-350

                              Comment

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