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Correct Timming for 5.7L

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  • Correct Timming for 5.7L

    Have twin 5.7L, 1987, ser# of one is OB741607. Have tied several sources to obtain the correct timming and have found both 10deg. and 8deg. BTC would like to know the correct or best setting for these engines.
    thanks.

  • #2
    Re: Correct Timming for 5.7L

    Originally posted by grewvin1 View Post
    Have twin 5.7L, 1987, ser# of one is OB741607. Have tied several sources to obtain the correct timming and have found both 10deg. and 8deg. BTC would like to know the correct or best setting for these engines.
    thanks.
    Ayuh,... Go up to Don'S Adults Only section, follow the links, 'n download the manual for Yer motors,...

    It'll tell ya what the timin's gotta be,...

    Go by yer serial numbers,...

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    • #3
      Re: Correct Timming for 5.7L

      They do that on purpose to keep us boaters on our toes. Make us do a little averages math and set our timing at 9. The real anus clencher is when you see a couple of manuals telling you to figure timing by purchasing tool J54827 which is a freakin slide rule. Anybody remember those?

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      • #4
        Re: Correct Timming for 5.7L

        Originally posted by Walt T View Post
        They do that on purpose to keep us boaters on our toes. Make us do a little averages math and set our timing at 9. The real anus clencher is when you see a couple of manuals telling you to figure timing by purchasing tool J54827 which is a freakin slide rule. Anybody remember those?
        Ayuh,.... Ain't even seen one since 'bout 1973 or so,...

        Luckily, electronic calculators came out 'bout that time,...
        alittle late to save my high school math grades, but a 'ell of alot easier for a Non-mathamagician,..

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        • #5
          Re: Correct Timming for 5.7L

          You mean one of these?



          I remember using one at high school. Got to be quite good at it. I still have mine from those days.... Not sure if I could get any sense out of it now though....

          Chris.....
          BTW, the latest manual for your engine calls it out at 8 degrees BTW.
          xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
          The world takes on a whole new perspective when viewed from 100’ below.
          1972 Bertram ‘Bahia Mar’ 20
          2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
          (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


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          • #6
            Re: Correct Timming for 5.7L

            Originally posted by grewvin1 View Post
            Have twin 5.7L, 1987, ser# of one is OB741607. Have tied several sources to obtain the correct timming and have found both 10deg. and 8deg. BTC would like to know the correct or best setting for these engines.
            thanks.
            Question do you have efi or a carbed version...makes a difference...by the way the boy's are play'n here
            Stickly a opinion your mileage may vary.

            Horsepower is how quickly you can get to the wall
            Torque is how far you move the wall"

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            • #7
              Re: Correct Timming for 5.7L

              Originally posted by Tail_Gunner View Post
              Question do you have efi or a carbed version...makes a difference...by the way the boy's are play'n here
              First 350s with EFI came out in 1995... His are '87, so I would guess it's carbed (also by the serial number, it's carbed. )
              xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
              The world takes on a whole new perspective when viewed from 100’ below.
              1972 Bertram ‘Bahia Mar’ 20
              2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
              (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


              Comment


              • #8
                Re: Correct Timming for 5.7L

                Originally posted by Tail_Gunner View Post
                Question do you have efi or a carbed version...makes a difference...by the way the boy's are play'n here
                Hey there Gunner, Just so your up to speed.... besides the 320 efi made between 1987-1989, Marine fuel injected as we know it today did not start until early 1993 with the 502 efi then progressed slowly with other engine models thereafter. grewvin1 serial number says he has a 1987 260 HP carbureted. Edit: Chris beat me to it.

                I'm with Walt, when in doubt set it to 9*

                Boatinfo - Mercruiser Service Manual nr. 9 - 1985-1988 - GM V8 Engines
                Last edited by Fun Times; March 3rd, 2014, 07:03 PM.
                OEM Quality Gear Lubes And Greases Available @ iboats.com 'By Bel-Ray Marine Lubricants -- BOAT SPECS -- FORUM GUIDELINES -- Volvo, OMC & Merc Stern Drive Technical Information For DIYers. -- OEM VOLVO PARTS POWERED BY iBOATS.COM -- All OEM Parts / Parts Lookup Now Available Through iboats.com --

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                • #9
                  Re: Correct Timming for 5.7L

                  FWIW I've always set carb'd 5.7 marine motors to 8 degrees.. 10 seams too much IMO.. also, I have a slide rule in my toolbox at work not that i use it, but its funny to prank apprentices with...
                  If I had all the money I've ever spent on boats over the years, I would spend it all on boats. Yup, because I'm stupid like that..

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                  • #10
                    Re: Correct Timming for 5.7L

                    Carb'ed 4 barrel Rochester, So 8deg BTC it is and I too have a slide rule to show the new young P.Eng engineers they are real screwed when looking at it. thanks to the gang. also will review Don's notes, God bless him.

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                    • #11
                      Re: Correct Timming for 5.7L

                      If you are running pump gas (E10) set it to 8 degrees before... If you are running 90 octane ethanol free recreational fuel you can set it to 10 if you want to. However, the power difference is negligible. You are really better off leaving it at 8, that way if you have any water/fuel issues your less likely to have detonation problems.
                      just because you found it that way does not mean it is supposed to be that way.

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                      • #12
                        Re: Correct Timming for 5.7L

                        Aviator Slide rule still in use: E6B - Wikipedia, the free encyclopedia (I know....so what! )

                        Comment


                        • #13
                          Re: Correct Timming for 5.7L

                          Originally posted by achris View Post
                          First 350s with EFI came out in 1995... His are '87, so I would guess it's carbed (also by the serial number, it's carbed. )
                          Originally posted by Fun Times View Post
                          Hey there Gunner, Just so your up to speed.... besides the 320 efi made between 1987-1989, Marine fuel injected as we know it today did not start until early 1993 with the 502 efi then progressed slowly with other engine models thereafter. grewvin1 serial number says he has a 1987 260 HP carbureted. Edit: Chris beat me to it.

                          I'm with Walt, when in doubt set it to 9*

                          Boatinfo - Mercruiser Service Manual nr. 9 - 1985-1988 - GM V8 Engines

                          ..........
                          Last edited by Tail_Gunner; March 4th, 2014, 11:28 AM.
                          Stickly a opinion your mileage may vary.

                          Horsepower is how quickly you can get to the wall
                          Torque is how far you move the wall"

                          Comment


                          • #14
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                            Re: Correct Timming for 5.7L

                            Originally posted by JustJason View Post
                            If you are running pump gas (E10) set it to 8 degrees before... If you are running 90 octane ethanol free recreational fuel you can set it to 10 if you want to. However, the power difference is negligible. You are really better off leaving it at 8, that way if you have any water/fuel issues your less likely to have detonation problems.
                            Im so glad fuel injection and computers exist.
                            2013 Bayliner 255CR
                            5.0MPI S/N:2A044802
                            http://seawenchnc.blogspot.com

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