Announcement

Collapse
No announcement yet.

Engine Cylinders pinging-gctid808772

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Engine Cylinders pinging-gctid808772

    I installed a rebuilt 454 7.4 with new 1409 Edelbrock carburetor and a rv.

    With timing set At 8 degrees before TDC and idle adjusted to 650 motor runs goodon low and mid range. When w.o.t is reached and mainted for more than couple seconds started pinging real bad. If I back off the timing tell it quits pinging and runs w.o.t at 3500 rpm. Then when I idle down it has horrible idle and when i turn up idle screw too maintain 650 rpms at idle it kicks the carb out of idle ciruit and runs too rich. Wondering if anyhing else could give me this problem thinking i have to jet the carb to run fatter on w.o.t. Any help much appreciated.

    Skeeter

    #2
    Well at a guess, the 1409 is used more on 350ish engines @650cfm

    The Edelbrock carb used most on BB size engines is a 1410. I would bet if you switched to the 1410 @750cfm the problem would disappear.
    Pat. Sandpoint Ida
    I NEED ANOTHER BOAT!!

    Comment


      #3
      650 cfm should cover that motor, but not if its high performance or otherwise higher horsepower, it could be a bit restrictive for that. I would say first things first you need a high volume fuel supply and a well vented gas tank, sounds like your running out of fuel and going lean to me.
      1990 3888 Bayliner, Twin 351's

      Comment


        #4
        A 1409 is normally jetted for a 350. A 454 can gulp 700 CFM with the right cam so the 1409 will work but it will restrict air flow. I think your problem is probably jetting. The 1409 is jetted when purchased for a 350 so you start running lean a few seconds after you get to any high RPM and the accelerator pump fuel burns off. Basically the 1409 is starving your engine of air and fuel, but starving it worse on the fuel side, which makes it lean if that makes any sense. I'm on my fourth beer so I probably shouldn't even be commenting (Alaskan Stout yum). Might be able to step up two jet sizes and get acceptable results, but a better flowing carb with bigger jets would probably get you more power. Cheers. Back to the fridge now.
        1995 4587
        2 X Hino 250s

        Comment


          #5
          You need a 6-8 psi fuel pump !

          What is the pump giving you ?

          Damn expensive for a carb nowadays. where you bought it did you tell them what engine and hp your running to get their opinion ?

          What did you do for a intake ?
          Be good, be happy, for tomorrow is promised to no man !

          1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

          '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

          Manalapan N.J

          Comment


            #6
            "FBKboater" post=808811 wrote:
            ............... A 454 can gulp 700 CFM with the right cam so the 1409 will work but it will restrict air flow. .
            [color]blue wrote:
            We typically operate our Marine Cruiser engines at below 4k rpm.

            A 454 cu in engine @ 4k rpm only requires approx 450 cfm.

            A 350 cu in engine @ 4k rpm only requires approx 345 cfm.

            If we were to take the 350 cu in engine up to 6k rpm, the cfm requirement becomes 516 cfm.

            516 cfm is still under the 454 cfm requirement @ under 4k rpm.

            [/color]

            .
            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
              (CID x MaxRPM) / 3456 = CFM,

              Or try this: https://www.holley.com/products/fuel...s/carburetors/

              Comment


                #8
                "SuperiorDiver" post=808822 wrote:
                (CID x MaxRPM) / 3456 = CFM,

                Or try this: https://www.holley.com/products/fuel...s/carburetors/
                While the Holley.com web page does mention "boats", every one of the Holley carburetors shown are for HP Automotive applications.

                1..... we cannot use a Holley with the external float level adjustment, nor with the fuel level "peep sites".

                2.... the fuel metering is most likely incorrect for the Marine Engine.

                .
                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
                  Sorry,

                  I was not suggesting using an automotive carbbie on a marine engine, just providing the formula to calculate CFM requirement.

                  Perhaps I'm incorrect, but I was thinking the CFM requirement was derived from the required air flow based on engine displacement and RPM, and of course A/F ratio could be adjusted to suit the application.

                  Comment


                    #10
                    "SuperiorDiver" post=808825 wrote:


                    ............. I was thinking the CFM requirement was derived from the required air flow based on engine displacement and RPM, and of course A/F ratio could be adjusted to suit the application.
                    [color]blue wrote:
                    That is correct!

                    For a 4 cycle engine, it would be the dynamic cubic foot displacement per one full cycle of all cylinders X's 1/2 engine revolutions.

                    For a 2 cycle engine, such as the old Detroit Diesels, it would be the dynamic cubic foot displacement per one full cycle of all cylinders Xs engine revolutions.

                    For a 4 cycle engine, the on-line CFM calculators take this all into account! [/color]

                    .
                    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


                      #11
                      It may be a jetting issue but Chief Allen may have a point. If the engine runs at WOT for a bit before pinging, it may be that the fuel pump is not keeping up with the demand. This will result in a lean mixture.
                      1999 3788, Cummins 270 "Freedom"
                      2013 Boston Whaler 130 SS
                      Anacortes, WA
                      Isla Verde, PR

                      Comment


                        #12
                        Run any engine for any amount of time lean your going to blow a hole in the piston.

                        Just sayin ...

                        I would see what the pump psi is giving ya !
                        Be good, be happy, for tomorrow is promised to no man !

                        1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                        '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                        Manalapan N.J

                        Comment


                          #13
                          Yep shouldn't post when drinking. I have an airboat that I run a 454 with a zz502 cam in that requires 700 CFM or better but it runs at 5300 to 5500 RPM all day, wasn't thinking about the low RPM on a boat. My calc on the 454 at 4K comes to 525 using the standard 3456 for CI measured 4 strokes how did get 450 unless you were account for volumetric efficiency loss?
                          1995 4587
                          2 X Hino 250s

                          Comment


                            #14
                            Most stock Mercruiser 454s got the 750 CFM.

                            Edelbrock 1410 works well on a 7.4.
                            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


                              #15
                              Most stock Mercruiser 454s got the 750 CFM.

                              Edelbrock 1410 works well on a 7.4.

                              +1
                              Pat. Sandpoint Ida
                              I NEED ANOTHER BOAT!!

                              Comment

                              Working...
                              X