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    #46
    ...........................
    Originally posted by Lineman1 View Post
    Talked to the machine shop today. If I can't get to 0.040 to 0.045 quench with a piston and head gasket combination I'll take 0.010 to 0.015 off the deck.
    Your SBC block deck height dimension should be 9.025". I would start with that, and do the math to learn what your piston deck height will be.

    And for clarity...... are you building a 6.3L?
    If building a Q/E 5.7L, I would shoot for a Quench dimension of .038", and if building a Q/E 6.3L, I would shoot for a Quench dimension of .043" or so.



    Like I said before there's dosen't seem much I can do with timing. Unless anyone knows someone who has hacked the 555 ecm? There don't seem to be any "block boxes" for the 555.

    OK..... you can increase the TA (total advance) simply by increasing the BASE or Initial advance.
    In other words, if you increase BASE by 3*, you will have increased TA by that same 3*.

    However, increasing BASE may create "bucking" during cranking! If so, then yes...... the controller would need to be altered so that the OEM BASE advance can be maintained, yet allow for more Progressive and TA.


    A good Quench Effect (via correct piston profile) and a good quench dimension should allow for an ignition advance of approx 32* @ 3,200 RPM, placing the LPCP @ 12* to 14* ATDC.

    Heads up...... you may find a few machine shops who will Foo Foo the Quench Effect idea, and tell you that it's not necessary. If so, I would suggest finding another shop.

    The first SBC V-8 incorporated a quench effect. It wasn't until the early 70s when the GM engineers came up with the full dished piston in an effort to reduce emissions.
    Also, the Chrysler Wedge Head enthusiasts have been using the Quench Effect for years and years.


    Good luck, and please keep us up to speed.

    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


      #47
      "OK..... you can increase the TA (total advance) simply by increasing the BASE or Initial advance.
      In other words, if you increase BASE by 3*, you will have increased TA by that same 3*."

      Not exactly... base timing is not adjustable on ECM 555... that it is set by Crank and Cam sensors.
      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

      Comment


        #48
        Your correct the only way to move the timing is in the ecm. I don't seem to have a cam sensor just crank Not sure I want to bet a $700 reflash on +3 or so timing?
        Why .043 on the quench are you worried about piston rock?
        1992 2452
        5.0 alpha1 gen2

        Comment


          #49
          Originally posted by Joon
          Not exactly... base timing is not adjustable on ECM 555... that it is set by Crank and Cam sensors.
          Originally posted by Lineman1 View Post
          You're correct the only way to move the timing is in the ecm. I don't seem to have a cam sensor just crank Not sure I want to bet a $700 reflash on +3 or so timing?
          OK.... if the Progressive and the TA cannot be adjusted (as to be increased), then the whole idea of creating a Quench Effect combustion chamber becomes diminished some.
          What a bummer when it can be so important and helpful for a Marine SBC build.


          FYI.... I began building SBCs in/around 1966 or so. At that time, most of them were HP auto engines.
          I have never built one using anything but a quench style piston, giving me a quench effect combustion chamber.
          I carried this practice over to the Marine world when I began doing Volvo Penta work.

          Many times detonation damage is mis-diagnosed, even by the best Marine mechanics.



          Originally posted by Lineman1 View Post
          Why .043 on the quench are you worried about piston rock?
          The 5.7L stroke is 3.480", whereas the 6.2L or 6.3L stroke is 3.750" .
          Pistons/rods are of the same approx mass, but are traveling at a greater velocity w/ the 3.750" stroke (not RPM, velocity!) and will stretch during the transition from approaching TDC to leaving TDC.
          If things didn't stretch, the Q/E dimension could be almost ZERO.

          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


            #50
            Rick is correct on the quench #s. Some racers run down to .025 on the piston to head clearance but that is with high tech high quality parts. Alot will run with .030 but they also know that catastrophe is possible but they are in it to win it.

            For a everyday marine application .038 is good. Me personally on a 5.7 i do .035 but not sure it makes a difference i wont go less than that.

            What you will notice with a good quench engine......

            increased compression wont have detonation problems ( to a point)

            improved torque and horsepower

            Increased fuel economy to the point that the extra expense will pay for its self in fuel savings .

            increased throttle response.

            probably what you will notice most is in fuel savings and extra torque.

            i run .035 with 10.8:1 with aluminum heads on pump gas regular.

            I just pulled out 2 -454 330hp big blocks 2 weeks ago and getting ready to install 2- 350 small blocks 380 hp quench built run on regular pump gas.

            My bet is it will do better than the big blocks.
            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


              #51
              Base timing is not adjustable, but the TA (total advance) can be...
              still I would leave it alone, put everything back stock.
              Also ECM 555 is working in conjunction with 2 knock sensors ( 1 per each bank ) to limit the spark advance to prevent detonation from occurring.
              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

              Comment


                #52
                Lineman, in spite of what some may suggest (building it in a standard fashion, etc), please understand that you will have a much better engine (6.3L stroker) if you build a quench effect into the combustion chamber!
                You can work out the ignition advance issue later!


                Read Dave’s post (post #50) again!

                .
                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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