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Attn Nottingham88..... engine timing hijack-gctid428463

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    Attn Nottingham88..... engine timing hijack-gctid428463

    nottingham88 wrote:
    In my search for more ooomph I ran water tests to graph the timing curve. The max advance I achieved was far below the max it could be from what I understand from vague info provided by MC. Here's what I saw during that test which was with new incorrect carb.

    650 - 10BTDC with module grounded per merc instructions.

    650 - swings around + or - a few degrees with module enabled. RPM is rock steady

    1280 - 12 BTDC

    1520 - 13 BTDC

    1750 - 13 BTDC

    2000 - 13 BTDC

    2500 - 14 BTDC

    3000 - 18 BTDC

    3500 - (3400) - 22 BTDC

    3750 - (3600) - 24 BTDC


    4000 - 25 BTDC (WOT maxxes around 4- 4100 with this prop and load)
    Something seems odd to me with these ignition advance numbers.

    Between 1280 and 2000, not much is going on.

    13* BTDC @ 2000, 14* @ 2500, 18* @ 3000, 22* @ 3500, and 24* @ 3750 are somewhat conservative, IMO.

    Your 25* @ 4000 could actually be occuring closer to your 3000 rpm range.

    Numbers like these typically place the LPCP too far after TDC, IMO. (ideal LPCP is between 12* and 14* ATDC)

    A lazy LPCP will prevent good low end torque.

    .
    Rick E. (aka RicardoMarine) 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

    Please, no PMs. Ask your questions on forum.

    #2
    2850Bounty wrote:
    Something seems odd to me with these ignition advance numbers.

    Between 1280 and 2000, not much is going on.

    13* BTDC @ 2000, 14* @ 2500, 18* @ 3000, 22* @ 3500, and 24* @ 3750 are somewhat conservative, IMO.

    Your 25* @ 4000 could actually be occuring closer to your 3000 rpm range.

    Numbers like these typically place the LPCP too far after TDC, IMO. (ideal LPCP is between 12* and 14* ATDC)

    A lazy LPCP will prevent good low end torque.

    .
    I agree with and understand your point up to the last sentence which confuses me somewhat. Could you explain your rational there please ? LDCP has left me acronym deficient.

    There are another couple of other points on the Tbird V module between 5.7 and 5.0 litre which may or may not be involved.

    I've looked at the schematics and see the knock module wiring is looped back on itself on the 5.0 while on the 5.7 that extends to and from the knock module. That suggests to me that the 5.7 is more prone to knock - hence the knock module ??? Or was it just the beancounters?

    It has been suggested the 5.7 uses a different model of ignition module to the 5.0 L but I have not confirmed that. I did confirm the venturi difference. That venturi BTW is very expensive IMO at about $200. That's why I bought spare carb from an '05 5.7L. Bolted right on and is perfect if I could just adjust the mixture easier without the cap on it

    The Delco Voyager EST system seems to max timing below 30 deg BTDC for any model (model specifies the initial timing) .

    In theory the TBOLT V is awesome when working properly. However economics do have to be considered sometimes along with preferences. I don't like having to use a shotgun approach because they don't provide any methods of testing or real life specs- only "typical" + or - of such huge amounts the info is useless to me. Why do I need 4 auto functions, sometimes simpler is more reliable.

    I didn't install the Delco set yet so I can't report on the difference. I have it just in case my theory is correct and the TBolt V ready to croak while I am wanting to fish more than pull spanners ! It's up for change next spring once I retest on the water so I can record timing while running with correct venturi.

    There's a lot going on in that TBOLT box and it's too expensive to replace on speculation. It was about half price for new delco c/w dist, coil, plug leads, spare dist cap and pickup than for the mysterious M/C black box. I dislike equipment that comes with no actual spec and no real way to prove full functionality. Doesn't Volvo and others use the delco voyager system and according to Mich Motorz the same one is used for both 5.0 and 5.7 without knock module ? I have read Delco is more reliable. At least they provide max timing spec.

    I was too busy with boating and fishing to have down time but did manage to schedule the other test and prop changes while the boat was in the water this summer. IMO you can only change one thing at a time to have a valid comparison.

    On the positive side I doubt I'll ever destroy this engine by too much advance but could use more power lower down to spin up more pitch. From what I have read of others with this boat/engine combo I know the prop I'm running is not the least in pitch but according to M/C and Trophy the stock is 19P for 5.7 and 17P for 5.0.

    Most say its all exactly the same and should work fine, it works well enough but IMO could work better. That's why I found Terry's post so interesting. Maybe he will turn up some new ideas or realities.
    2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

    Comment


      #3
      It gets quite involved, so I'll try to nut shell this, but it may be a rather large nut shell.

      LPCP = location of peak cylinder pressure..... I.E., when the gasses have reached the maximum expansion relative to crankshaft angle.

      Many engineers will suggest that 12* to 14* ATDC is ideal.

      That's "After" top dead center!

      This gives the piston the greatest downward force advantage against the crankshaft and at the optimal crankshaft angle.

      This would apply to a lawn mower engine, boat engine, car/truck engine, gas, diesel, or any piston type engine.

      Fuel/air, camshaft profile, piston design, C/R, cylinder combustion chamber design, etc, all play an important role in this..... and lastly, Ignition Advance!

      Advance that is too early, and the LPCP also occurs too early, and detonation may occur, along with excessive cylinder temperatures. Severe damage may occur.

      Advance that is too late, and the LPCP also occurs too late, and power is sacrificed. Normally no damage is sustained.

      Yes, most all new Marine Engines use some form of EST ignition system today.

      All spark lead is done via the electronics within the control unit.

      No mechanical advance.

      As with any ignition, BASE advance is a result of the distributor housing indexing to crankshaft angle.

      You mentioned that the Delco Voyager EST system seems to max timing below 30 deg BTDC for any model.

      Just an FYI: Max advance numbers are rather meaningless without an associated RPM.

      With your Vortec 5.7L, you'll have the full dished pistons.

      C/R, cam profile, etc. will be correct, but this piston does not create an optimal combustion chamber for much ignition advance.

      IOW, these pistons should never see excessive advance numbers, even if this means a less than desirable LPCP.

      Bottom line.... you are safe being rather conservative with your TA (total advance) for this engine.

      BTW, Marine engine advance numbers at/near 4k rpm are typically not as important as if at let's say at/near 3.2k rpm since we seldom operate at/near 4k rpm.

      At/near 3.2k rpm is where detonation potential may be greater.

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

      Here are three sample ignition advance curves for conversation ONLY.

      I'm not suggesting that these are correct for your engine.

      Note that these curves almost always omit showing BASE advance in the vertical scale. What is shown is the actual distributor advance (or EST advance) minus BASE advance.

      So when using these curve graphs, BASE advance numbers must be added when doing the math and when putting the numbers to use dynamically.

      Conversely, when we strobe our timing marks (standard timing light), BASE can't help but be included in what we see.

      This would be so for Mechanical or EST.

      If you were to over-lay your advance numbers at your 1280 rpm to 2000 rpm range (where your actual advance number is only 13*), you'd see that the curve line would be rather flat until it begins to increase at/near 2500 rpm and up.

      Many are rather linear, and perhaps ramp up a bit at first.

      That's what seems odd to me about your numbers.

      Attached files [img]/media/kunena/attachments/vb/732463=33185-Merc ignition curve by Mark for Kirk.jpg[/img] [img]/media/kunena/attachments/vb/732463=33183-OMC 5.8L ignition advance curve 2 john rupp.jpg[/img] [img]/media/kunena/attachments/vb/732463=33184-Sample ignition curve graph.jpg[/img]
      Rick E. (aka RicardoMarine) 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

      Please, no PMs. Ask your questions on forum.

      Comment


        #4
        Thanks for that explanation - I think I understand now. What I got was that the advance is relative to RPM and the advance curve should be designed to keep the LDCP at the optimum range of 12-14* After TDC.

        If LDCP is any sooner it may be bad news and if later you may not be developing optimum power from your engine. Thanks.

        When I win the lotto I will get a remote camera so I can peek inside the plug hole and see what's in there for piston tops

        I'm not sure if Terry has Tbolt IV or Tbolt V on his engine. If it is Tbolt V his results may help.
        2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

        Comment


          #5
          Wow.

          I wish the science lessons at school were as well taught as that which I am reading here . . .
          Terry (Retired Diving Instructor and Part Time IT Consultant)
          1998 Bayliner 2452. 5.7l V8 - Edelbrock 1409 4bbl - Alpha1Gen2 - Solent UK.
          MMSI 235061726

          Comment


            #6
            nottingham88, just for the heck of it, I took your numbers and over-layed them onto my example curve graph.

            Since you show 10* @ 650 rpm, I assumed that this was your BASE advance.

            If that is correct, I've used that number and backed out 10* when I laid the data onto the graph as per each RPM increment.

            (I messed up and show this @ 850 rpm.... but it won't matter much)

            Here's what your curve would look like "IF" your numbers are accurate (see first image).

            As you can see, your numbers deviate quite a bit from a known-to-be-good SBC Marine Engine ignition advance curve (black lines).

            NOTE: the two curves shown in black may be minus a BASE advance of only 6* to 8*.

            The curve shown in red is minus what I assumed to be your BASE of 10*.

            This means that 10* must be added in order to show what your strobe light would reveal while checking timing advance dynamically (as shown in the second image).

            Looks as though your Full-In spark advance is being held back until 4k rpm, and is only 25*.

            More or equally important, is the advance at/near 3k rpm, of which is only 18* or so.

            (typically we'll see approx 26* maybe 28* @ 3.2k rpm for a SBC w/ full dished pistons)

            I'll tell you this..... if these numbers are correct, and unless you were to over-heat this engine, or lean out your fuel/air mixture, I'll personally guarantee all 8 of your pistons against detonation damage!

            I'm going to also suggest that you are leaving a considerable amount of horse power and torque on the table if this curve is what your engine is seeing.

            But again..... this works out only if your numbers are correct.

            (I say "correct" as in what you are actually seeing, because in no way are these correct for any performance!)

            I've posted a third image that is used for the Volvo Penta 5.7L engine that you could make a comparison to.

            Again, as per the vertical scale, this curve is minus BASE advance.

            Attached files [img]/media/kunena/attachments/vb/732682=33205-Ignition advance curve for nottingham88 2.jpg[/img] [img]/media/kunena/attachments/vb/732682=33204-Ignition advance curve for nottingham88.jpg[/img] [img]/media/kunena/attachments/vb/732682=33212-Ignition advance line graph VP 5.7L .jpg[/img]
            Rick E. (aka RicardoMarine) 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

            Please, no PMs. Ask your questions on forum.

            Comment


              #7
              2850Bounty wrote:
              nottingham88, just for the heck of it, I took your numbers and over-layed them onto my example curve graph.

              Since you show 10* @ 650 rpm, I assumed that this was your BASE advance.

              If that is correct, I've used that number and backed out 10* when I laid the data onto the graph as per each RPM increment.

              (I messed up and show this @ 850 rpm.... but it won't matter much)

              Here's what your curve would look like "IF" your numbers are accurate (see first image).

              As you can see, your numbers deviate quite a bit from a known-to-be-good SBC Marine Engine ignition advance curve (black lines).

              NOTE: the two curves shown in black may be minus a BASE advance of only 6* to 8*.

              The curve shown in red is minus what I assumed to be your BASE of 10*.

              This means that 10* must be added in order to show what your strobe light would reveal while checking timing advance dynamically (as shown in the second image).

              Looks as though your Full-In spark advance is being held back until 4k rpm, and is only 25*.

              More or equally important, is the advance at/near 3k rpm, of which is only 18* or so.

              (typically we'll see approx 26* maybe 28* @ 3.2k rpm for a SBC w/ full dished pistons)

              I'll tell you this..... if these numbers are correct, and unless you were to over-heat this engine, or lean out your fuel/air mixture, I'll personally guarantee all 8 of your pistons against detonation damage!

              I'm going to also suggest that you are leaving a considerable amount of horse power and torque on the table if this curve is what your engine is seeing.

              But again..... this works out only if your numbers are correct.

              (I say "correct" as in what you are actually seeing, because in no way are these correct for any performance!)

              I've posted a third image that is used for the Volvo Penta 5.7L engine that you could make a comparison to.

              Again, as per the vertical scale, this curve is minus BASE advance.
              Bounty2850 - Thanks for your input. The readings I took were using an advance timing light and to the best of my knowledge I am using it correctly. We discussed that a couple of years back. To that end I had my initial setting checked by someone who uses those 'modern' tools for a living.

              When asked if I should add the initial to the actual reading I was getting from the advance timing light I was told a definate NO - not with an advance timing light because the electronics do that for you as long as you reset to zero to start with.

              His snap on showed exactly what I set - 10 BTDC as accurate. ( Module disabled) Because we were using a flush kit we didn't exceed 1500 RPM but did see that the advance function was working- ie the total timing went up slightly.

              I do understand and agree with your explanation of subtracting the intial 10* BTDC from subsequent readings to show what the module is adding or subtracting from the actual reading as long as you have adjusted to line up the "block" mark to the damper mark at whatever RPM.

              So if my light shows 25* undeway that is 10* initial and 15* provided as advance function from the module under whatever functional range the RPM is in. By functional range I refer to the TBolt V's internal programming (auto adjustments in several RPM ranges).

              Funny you mention the 4K mark - I'm pretty sure thats where the TBV auto functions drop out other than over rev protection which strangely enough I have never experienced

              With the knowledge of someone like yourself we can at least compare what we would typically expect for a marine SBC to what the test readings tell us we're actually getting. I fully expected to see a curve more typical of what you show.

              It's too easy to get lost in terminology like Intial timing, advance curve and total timing (aggregate total). It's really not that complex but easily misunderstood. The numbers I showed were total timing with module properly enabled.

              I also doubt I'll ever kill this engine from too much timing the way it set but I am intent on recovering the power I'm missing. Problem is we get boat in water only away from home and the reason for being there is get fishy hands - not greasy ones

              I've heard that slow work takes time- especially when your not very good at it - that descibes my progress on this ongoing issue.

              While the TboltV may be smarter than the Delco Voyager EST my guess is the Delco will outperform because it will be fully functional.

              When I make more progress in this I will post what I get. It won't be until 2013 though. I apologise to Terry if I have detracted from his original thread - .
              2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

              Comment


                #8
                nottingham88 wrote:
                Bounty2850 - Thanks for your input. The readings I took were using an advance timing light and to the best of my knowledge I am using it correctly. We discussed that a couple of years back. To that end I had my initial setting checked by someone who uses those 'modern' tools for a living.

                [COLOR]"#0000FF" wrote:
                I have no issue with a high quality Digitally Advancing timing lights if the user knows how to work the unit correctly. It can be very accurate.

                However, my preference is to strobe a marked off balancer with a standard light and see real degress in real time.

                [/COLOR]

                When asked if I should add the initial to the actual reading I was getting from the advance timing light I was told a definate NO - not with an advance timing light because the electronics do that for you as long as you reset to zero to start with.

                [COLOR]"#0000FF" wrote:
                I'm not quite understanding why the mechanic would bother to strobe the timing marks, and then back out BASE advance on his display, unless he was trying to show you what the module ONLY advancing was.

                If he adjusted the light to accommodate the 10* of BASE, then what he showed you would have been the actual module ONLY advance.

                If that is what he was doing, he could have simply plotted the numbers out, and then deducted the BASE advance.

                Personally, I always want to see the actual advance in full crankshaft degrees since I already know what I set the BASE at.

                See ** below.

                [/COLOR]

                His snap on showed exactly what I set - 10 BTDC as accurate. ( Module disabled) Because we were using a flush kit we didn't exceed 1500 RPM but did see that the advance function was working- ie the total timing went up slightly.

                [COLOR]"#0000FF" wrote:
                I must call BS on that. We do this all the time in order to check TA.

                A rule to NOT Exceed 1,500 rpm while on the muffs is a misnomer. You just don't want to sustain a higher RPM for any duration.

                We just barely leave BASE advance at 1,500 rpm and begin with the progressive. If we don't increase RPM, we can't see the TA.

                [/COLOR]

                I do understand and agree with your explanation of subtracting the intial 10* BTDC from subsequent readings to show what the module is adding or subtracting from the actual reading as long as you have adjusted to line up the "block" mark to the damper mark at whatever RPM.

                [COLOR]"#0000FF" wrote:
                Correct. [/COLOR]

                So if my light shows 25* undeway that is 10* initial and 15* provided as advance function from the module under whatever functional range the RPM is in. By functional range I refer to the TBolt V's internal programming (auto adjustments in several RPM ranges).

                [COLOR]"#0000FF" wrote:
                Yes, 10* BASE + 15* progressive = 25* TA, but an associated RPM is missing from this.

                BTW, short of knock sensor influence, or short of being a more sophisticated MPI ignition system, the advance for your system is not dependant on load. [/COLOR]

                Funny you mention the 4K mark - I'm pretty sure thats where the TBV auto functions drop out other than over rev protection which strangely enough I have never experienced

                [COLOR]"#0000FF" wrote:
                That's OK.... some curves will carry out the progressive advance much higher than need be.

                You'll see some that continue up to 4k rpm and then flatten out....., and you'll see some that flatten out at 3.5k rpm. [/COLOR]

                With the knowledge of someone like yourself we can at least compare what we would typically expect for a marine SBC to what the test readings tell us we're actually getting. I fully expected to see a curve more typical of what you show.

                [COLOR]"#0000FF" wrote:
                Same here........ and that is what puzzles me.

                It may be worth checking these numbers again. [/COLOR]

                It's too easy to get lost in terminology like Intial timing, advance curve and total timing (aggregate total). It's really not that complex but easily misunderstood. The numbers I showed were total timing with module properly enabled.

                [COLOR]"#0000FF" wrote:
                All we need to know is that BASE is BASE... we fire on BASE, we idle on BASE.

                The progressive is what occurs on top of BASE from BASE RPM to the RPM at which the advance discontinues.

                Like said..... when strobing your timing marks, you can't help but see BASE + the progressive, unless you were to adjust the digitally advancing light to accommodate. But why do that? [/COLOR]

                I also doubt I'll ever kill this engine from too much timing the way it set but I am intent on recovering the power I'm missing. Problem is we get boat in water only away from home and the reason for being there is get fishy hands - not greasy ones

                [COLOR]"#0000FF" wrote:
                Not following you on this one, unless you are refering to your curve as per what it shows below.

                I could take almost any SBC Marine engine (others also), adjust out the progressive advance, load the engine enough to cause it to detonate and self destruct.

                So don't underestimate how easily this can occur..... especially with a non-quench style SBC combustion chamber.

                [/COLOR]
                **

                OEM timing specs will typically call out BASE and TA, while ignition curve graphs will typically omit showing BASE advance.

                What we see while strobing the timing marks (while in standard timing light mode), will be exactly what the engine sees in crankshaft degrees.

                Example only:

                BASE of 8* BTDC and a total advance of 36* BTDC @ 4,200 RPM.

                While the BASE is only 8*, what you should see at 4,200 rpm would be 36*.

                Change the BASE to 6*, and the TA will now be 34*.

                Whether you are seeing 34* or 36*, this number reflects the sum of BASE and progressive.... not one or the other alone.

                Here are the two overlays of your module advance on top of a typical SBC advance curve again.

                First one is minus BASE.

                Look at the 3k rpm mark. It's showing 8*. Add BASE of 10*, and you're at 18* @ 3k rpm.



                Second one includes BASE.

                Look at the 3k rpm mark. It's showing 18*. No need to add BASE.... again, you're at 18* @ 3k rpm.



                I don't know of any SBC Marine engine that will run well @ 3k rpm with only 18* of ignition advance.

                That's whay these numbers don't make sense to me.

                .
                Rick E. (aka RicardoMarine) 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

                Please, no PMs. Ask your questions on forum.

                Comment


                  #9
                  Legend Nott88 black and then red while bounty2850 is blue. Quoted and appended from Bounty's answer.

                  Originally Posted by nottingham88

                  Bounty2850 - Thanks for your input. The readings I took were using an advance timing light and to the best of my knowledge I am using it correctly. We discussed that a couple of years back. To that end I had my initial setting checked by someone who uses those 'modern' tools for a living.

                  I have no issue with a high quality Digitally Advancing timing lights if the user knows how to work the unit correctly. It can be very accurate.

                  However, my preference is to strobe a marked off balancer with a standard light and see real degress in real time.


                  They are actually pretty easy to use. I do like it and have no problem with the technolgy. Its a lot easier than trying to degree the dampener in boat, let alone get accurate TDC via plughole that I can not even see

                  When asked if I should add the initial to the actual reading I was getting from the advance timing light I was told a definate NO - not with an advance timing light because the electronics do that for you as long as you reset to zero to start with.

                  I'm not quite understanding why the mechanic would bother to strobe the timing marks, and then back out BASE advance on his display, unless he was trying to show you what the module ONLY advancing was.

                  If he adjusted the light to accommodate the 10* of BASE, then what he showed you would have been the actual module ONLY advance.

                  If that is what he was doing, he could have simply plotted the numbers out, and then deducted the BASE advance.

                  Personally, I always want to see the actual advance in full crankshaft degrees since I already know what I set the BASE at.

                  See ** below.


                  That's not what he did. When I said reset to zero that meant reset the timing light to zero when you start. You next need to + or - on the timing light to get the strobe to line up the marks- no degree wheel just a zero mark on these. Done properly WYSIWYG. The actual reading would depend on whether the module was enabled or disabled. If enabled you can then expect to see your base plus or minus the influence of Idle Speed Control. If disabled you should see 10*BTDC eaxactly.

                  IDLE SPEED SPARK CONTROL

                  The Ignition Module controls ignition timing to maintain a calibrated idle speed by making

                  small spark advance adjustments. This feature is only active between 400-700 rpm.

                  The amount of that control can be plus or minus about 8 degrees - per mercs graph.


                  His snap on showed exactly what I had set - 10 BTDC. ( Module disabled) Because we were using a flush kit we didn't exceed 1500 RPM but did see that the advance function was working- ie the total timing went up slightly

                  I must call BS on that. We do this all the time in order to check TA.

                  A rule to NOT Exceed 1,500 rpm while on the muffs is a misnomer. You just don't want to sustain a higher RPM for any duration


                  It's ME that makes that call. I have seen a Gen2 suck a hose flat so don't take any chances. The gen 2 pump is high volume low pressure. Don't try that on too long of a garden hose

                  With the knowledge of someone like yourself we can at least compare what we would typically expect for a marine SBC to what the test readings tell us we're actually getting. I fully expected to see a curve more typical of what you show.

                  Same here........ and that is what puzzles me.

                  It may be worth checking these numbers again


                  I did and there was a little change but then again look what that black box is capable of doing

                  ACCELERATION SPARK ADVANCE

                  When accelerating, the Ignition Module may add more spark advance to the ÔÇ£Base Spark

                  Timing Curve.ÔÇØ The amount of spark advance added depends on how fast rpm increases.

                  This feature is also active between 1200-4000 rpm. Within this range, the module can add

                  approximately 10 degrees of spark advance to the base spark timing curve.

                  MEAN-BEST-TIMING (MBT) SPARK ADVANCE

                  During light load cruising, the Ignition Module maintains optimal ignition timing by making

                  small spark advance adjustments. At a given rpm, the module will add a small amount of

                  advance and wait to see if there is an rpm change. If rpm increases, it will increase timing

                  more. The module will continue to advance timing until it no longer gets an increase in rpm.

                  Conversely, if it senses an rpm drop, it will start to retard some of the spark timing. Between

                  1200-4000 rpm the Ignition Module can add approximately 10-15 degrees of spark advance

                  to the base spark timing curve.

                  I doubt I'd get exactly the same reading 2 runs on diffent days for a variety of reasons. Especially if the TBV was not up to snuff


                  So if my light shows 25* underway that is 10* initial and 15* provided as advance function from the module under whatever functional range the RPM is in. By functional range I refer to the TBolt V's internal programming (auto adjustments in several RPM ranges).

                  Yes, 10* BASE + 15* progressive = 25* TA, but an associated RPM is missing from this.

                  BTW, short of knock sensor influence, or short of being a more sophisticated MPI ignition system, the advance for your system is not dependant on load
                  .

                  NO RPM given, it was an example only. I think the TBV is pretty smart too, these functions are active between 1200 and 4000 RPM.

                  ACCELERATION SPARK ADVANCE

                  When accelerating, the Ignition Module may add more spark advance to the ÔÇ£Base Spark

                  Timing Curve.ÔÇØ The amount of spark advance added depends on how fast rpm increases.

                  This feature is also active between 1200-4000 rpm. Within this range, the module can add

                  approximately 10 degrees of spark advance to the base spark timing curve.

                  MEAN-BEST-TIMING (MBT) SPARK ADVANCE

                  During light load cruising, the Ignition Module maintains optimal ignition timing by making

                  small spark advance adjustments. At a given rpm, the module will add a small amount of

                  advance and wait to see if there is an rpm change. If rpm increases, it will increase timing

                  more. The module will continue to advance timing until it no longer gets an increase in rpm.

                  Conversely, if it senses an rpm drop, it will start to retard some of the spark timing. Between

                  1200-4000 rpm the Ignition Module can add approximately 10-15 degrees of spark advance

                  to the base spark timing curve.

                  Because of the above I disagree with your statement that load has no effect


                  Funny you mention the 4K mark - I'm pretty sure thats where the TBV auto functions drop out other than over rev protection which strangely enough I have never experienced

                  That's OK.... some curves will carry out the progressive advance much higher than need be.

                  You'll see some that continue up to 4k rpm and then flatten out....., and you'll see some that flatten out at 3.5k rpm.


                  TBV is 10* + about 25 * if properly functioning at 4001 RPM. NOTE if fully functional. Like I've said- I don't think this one is fully functional.

                  With the knowledge of someone like yourself we can at least compare what we would typically expect for a marine SBC to what the test readings tell us we're actually getting. I fully expected to see a curve more typical of what you show.

                  Same here........ and that is what puzzles me.

                  It may be worth checking these numbers again.


                  I will, after I change to the delco system or another TBV. I'm a lot more confident using the advanced timing light after working with my neighbour. Before I was doubting myself because the readings were so wonky. He made it clear I was using the correct method and that the mark on dampener was zero. I set the base dead on using the same method I used on the water to take those RPM readings UNDER LOAD

                  I also doubt I'll ever kill this engine from too much timing the way this particular TBV is functioning but I am intent on recovering the power I'm missing. Problem is we get the boat in the water only away from home and the reason for being there is get fishy hands - not greasy ones

                  Not following you on this one, unless you are refering to your curve as per what it shows below.

                  I could take almost any SBC Marine engine (others also), adjust out the progressive advance, load the engine enough to cause it to detonate and self destruct.

                  So don't underestimate how easily this can occur..... especially with a non-quench style SBC combustion chamber.


                  That's why I don't over advance engines like many do and I don't run engines wide open EXCEPT to check WOT for correct prop. With such retarded timing how could it ever detonate. I do understand that can destroy an engine in seconds. I know we're not extracting extracting maximum HP. We go there to relax and catch fish. A good day ends with fishy hands not greasy ones.

                  To reiterate we just recorded what the advance timing light displayed when the marks were lined by adjusting the controls on the advanced timing light. The module was enabled for all readings except when we set base. The ignition was turned off to disable the module for base and also to re-enable by removing ground. We recorded the RPM and advance from the display on the light.

                  It wasn't easy, the Admiral was at the controls calling and holding the RPM and I had my head stuck in the engine box. We also checkd the dash tach was close enough to the RPM display shown on timing light. We think we did a thorough and accurate job. If my base settings were confirmed by a very experienced mechanic then I would suggest my advanced timing light was properly used and is accurate enough for me. Thanks for your input.

                  2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

                  Comment


                    #10
                    Geeze, now what text color am I going to use? :kidding Let's see..... [COLOR]#006400 wrote:
                    how 'bout green? [/COLOR]


                    BTW.... I have no dog in any fight here.... I'm just making conversation. You do what's best for you.... fair nuff?

                    ********

                    I'm not an expert with Merc's TB or any of the other EST ignition systems.

                    But I do know that when triggering an electrical spark event, we cannot expect the spark event to show up at a destination earlier than the original triggering event. The Laws of Physics prevent this!

                    This means that with the EST Ignition System, the spark triggering event is actually way ahead of what's required, and that the EST Ignition Module then delays the destination event via the electronic circuitry and the algorythms used.

                    IOW, since there is no advancing occuring within the ignition distributor, the predetermined and progressive delays ("advance") are entirely up to the ignition module to provide.

                    Just to be clear..... the EST "delay" still equates to a cylinder spark event that is advanced from crankshaft angle as per OEM ignition advance specs.

                    With mechanical advancing system, there is no need for a delay. The spark triggering event is in "real time" with the destination event (minus the limitations of 186,000 miles a second or 700 million miles an hour).

                    nottingham88 wrote:


                    Originally Posted by nottingham88

                    Bounty2850 - Thanks for your input. The readings I took were using an advance timing light and to the best of my knowledge I am using it correctly. We discussed that a couple of years back. To that end I had my initial setting checked by someone who uses those 'modern' tools for a living.

                    [COLOR]#0000cd wrote:
                    I have no issue with a high quality Digitally Advancing timing lights if the user knows how to work the unit correctly. It can be very accurate.

                    However, my preference is to strobe a marked off balancer with a standard light and see real degress in real time.[/COLOR]

                    [COLOR]#ff0000 wrote:
                    They are actually pretty easy to use. I do like it and have no problem with the technolgy. Its a lot easier than trying to degree the dampener in boat, let alone get accurate TDC via plughole that I can not even see

                    [/COLOR][COLOR]#006400 wrote:
                    To my knowledge, there's no timing light avaialbe that is capable of finding true TDC. This is up to us via a PPS procedure if in doubt.

                    [/COLOR][SIZE]3 wrote:
                    [COLOR]#006400 wrote:
                    If such a timing light exists, I want one! [/COLOR]
                    [/SIZE][COLOR]#006400 wrote:


                    That would be a pretty darn smart timing light if it was capable of seeing where the crankshaft angle was in relationship to the timing marks, and to then give us an "OK" signal.

                    IOW, if the TDC marks are inaccurate, it will not matter what timing light is used........ the ignition timing results will still be inaccurate. [/COLOR]

                    When asked if I should add the initial to the actual reading I was getting from the advance timing light I was told a definate NO - not with an advance timing light because the electronics do that for you as long as you reset to zero to start with.

                    [COLOR]#0000cd wrote:
                    [COLOR]#0000cd wrote:
                    I'm not quite understanding why the mechanic would bother to strobe the timing marks, and then back out BASE advance on his display, unless he was trying to show you what the module ONLY advancing was.

                    If he adjusted the light to accommodate the 10* of BASE, then what he showed you would have been the actual module ONLY advance.

                    If that is what he was doing, he could have simply plotted the numbers out, and then deducted the BASE advance.

                    Personally, I always want to see the actual advance in full crankshaft degrees since I already know what I set the BASE at.

                    See ** below.[/COLOR] [/COLOR]

                    [COLOR]#ff0000 wrote:
                    That's not what he did. When I said reset to zero that meant reset the timing light to zero when you start. You next need to + or - on the timing light to get the strobe to line up the marks- no degree wheel just a zero mark on these. Done properly WYSIWYG. The actual reading would depend on whether the module was enabled or disabled. If enabled you can then expect to see your base plus or minus the influence of Idle Speed Control. If disabled you should see 10*BTDC eaxactly.

                    [/COLOR][COLOR]#006400 wrote:
                    WYSIWYG applies to a standard timing light, or a digitally advancing light while in standard mode if you are refering to the OEM timing marks.

                    But I understand what you are saying.

                    [/COLOR]

                    His snap on showed exactly what I had set - 10 BTDC. ( Module disabled) Because we were using a flush kit we didn't exceed 1500 RPM but did see that the advance function was working- ie the total timing went up slightly

                    [COLOR]#0000cd wrote:
                    I must call BS on that. We do this all the time in order to check TA.

                    A rule to NOT Exceed 1,500 rpm while on the muffs is a misnomer. You just don't want to sustain a higher RPM for any duration[/COLOR]

                    [COLOR]#ff0000 wrote:
                    It's ME that makes that call. I have seen a Gen2 suck a hose flat so don't take any chances. The gen 2 pump is high volume low pressure. Don't try that on too long of a garden hose

                    [/COLOR][COLOR]#006400 wrote:
                    Again.... a common misnomer. The statement by the OEM is intended to be a disclaimer so that DIY'r Joe doesn't mess up, and then try to blame the OEM.

                    The only hose that could become sucked flat (Merc A drive) would be the garden hose. In which case the water volume may not be high enough. Try increasing the flow!

                    Remember..... we're increasing RPM just long enough to see what the advance is doing at 3k or so rpm, and for about 2-3 seconds only.

                    [/COLOR]

                    With the knowledge of someone like yourself we can at least compare what we would typically expect for a marine SBC to what the test readings tell us we're actually getting. I fully expected to see a curve more typical of what you show. [COLOR]#0000ff wrote:


                    [/COLOR][COLOR]#0000cd wrote:
                    Same here........ and that is what puzzles me.

                    It may be worth checking these numbers again[/COLOR]

                    [COLOR]#ff0000 wrote:
                    I did and there was a little change but then again look what that black box is capable of doing

                    ACCELERATION SPARK ADVANCE

                    When accelerating, the Ignition Module may add more spark advance to the ÔÇ£Base Spark

                    Timing Curve.ÔÇØ The amount of spark advance added depends on how fast rpm increases.

                    This feature is also active between 1200-4000 rpm. Within this range, the module can add

                    approximately 10 degrees of spark advance to the base spark timing curve.

                    MEAN-BEST-TIMING (MBT) SPARK ADVANCE

                    During light load cruising, the Ignition Module maintains optimal ignition timing by making

                    small spark advance adjustments. At a given rpm, the module will add a small amount of

                    advance and wait to see if there is an rpm change. If rpm increases, it will increase timing

                    more. The module will continue to advance timing until it no longer gets an increase in rpm.

                    Conversely, if it senses an rpm drop, it will start to retard some of the spark timing. Between

                    1200-4000 rpm the Ignition Module can add approximately 10-15 degrees of spark advance

                    to the base spark timing curve.

                    I doubt I'd get exactly the same reading 2 runs on diffent days for a variety of reasons. Especially if the TBV was not up to snuff

                    [/COLOR][COLOR]#006400 wrote:
                    As said, [/COLOR][COLOR]#006400 wrote:
                    I'm not an expert with the TB ignition systems. If you are comfortable with your numbers, there ya go!

                    All I did was to plot them out, and overlay them as to show a comparison. [/COLOR]

                    So if my light shows 25* underway that is 10* initial and 15* provided as advance function from the module under whatever functional range the RPM is in. By functional range I refer to the TBolt V's internal programming (auto adjustments in several RPM ranges).

                    [COLOR]#0000cd wrote:
                    Yes, 10* BASE + 15* progressive = 25* TA, but an associated RPM is missing from this.

                    BTW, short of knock sensor influence, or short of being a more sophisticated MPI ignition system, the advance for your system is not dependant on load[/COLOR].

                    [COLOR]#ff0000 wrote:
                    NO RPM given, it was an example only.

                    [/COLOR][COLOR]#006400 wrote:
                    Point was......... without an associated RPM, the numbers are worthless to me or any mechanic. [/COLOR][COLOR]#ff0000 wrote:


                    ACCELERATION SPARK ADVANCE

                    When accelerating, the Ignition Module may add more spark advance to the ÔÇ£Base Spark

                    Timing Curve.ÔÇØ The amount of spark advance added depends on how fast rpm increases.

                    This feature is also active between 1200-4000 rpm. Within this range, the module can add

                    approximately 10 degrees of spark advance to the base spark timing curve.

                    MEAN-BEST-TIMING (MBT) SPARK ADVANCE

                    During light load cruising, the Ignition Module maintains optimal ignition timing by making

                    small spark advance adjustments. At a given rpm, the module will add a small amount of

                    advance and wait to see if there is an rpm change. If rpm increases, it will increase timing

                    more. The module will continue to advance timing until it no longer gets an increase in rpm.

                    Conversely, if it senses an rpm drop, it will start to retard some of the spark timing. Between

                    1200-4000 rpm the Ignition Module can add approximately 10-15 degrees of spark advance

                    to the base spark timing curve.

                    Because of the above I disagree with your statement that load has no effect

                    [/COLOR][COLOR]#006400 wrote:
                    OK... if the load does offer an effect, then the system must be monitoring manifold pressure, and perhaps throttle position, etc.

                    However, it appears to me that your numbers are too far off to reflect this amount of controller adjustment.

                    What's up with a module that is giving only 18* of advance @ 3k rpm..... load or NO load?????

                    I guess that I don't understand that part.

                    [/COLOR]

                    Funny you mention the 4K mark - I'm pretty sure thats where the TBV auto functions drop out other than over rev protection which strangely enough I have never experienced

                    [COLOR]#0000cd wrote:
                    That's OK.... some curves will carry out the progressive advance much higher than need be.

                    You'll see some that continue up to 4k rpm and then flatten out....., and you'll see some that flatten out at 3.5k rpm. [/COLOR]

                    [COLOR]#ff0000 wrote:
                    TBV is 10* + about 25 * if properly functioning at 4001 RPM. NOTE if fully functional. Like I've said- I don't think this one is fully functional.

                    [/COLOR][COLOR]#006400 wrote:
                    10* + about 25* would equal about 35* @ 4001 RPM.

                    My question would be.... what's it doing at perhaps the more critical 3.2k rpm?

                    [/COLOR]

                    With the knowledge of someone like yourself we can at least compare what we would typically expect for a marine SBC to what the test readings tell us we're actually getting. I fully expected to see a curve more typical of what you show.

                    [COLOR]#0000cd wrote:
                    Same here........ and that is what puzzles me.

                    It may be worth checking these numbers again.[/COLOR]

                    [COLOR]#ff0000 wrote:
                    I will, after I change to the delco system or another TBV. I'm a lot more confident using the advanced timing light after working with my neighbour. Before I was doubting myself because the readings were so wonky. He made it clear I was using the correct method and that the mark on dampener was zero. I set the base dead on using the same method I used on the water to take those RPM readings UNDER LOAD

                    [/COLOR][COLOR]#006400 wrote:
                    How did he know that the markings on the balancer and the pointer were both accurate?

                    Like said, a timing light cannot determine this.

                    All the timing light is capable of doing, would be to use these markings as the base line for true TDC, and then reflect the following timing data from that.

                    TDC markings good...... then your timing will be good.

                    TDC markings off........ then your timing will be off by the same amount.

                    [/COLOR]

                    I also doubt I'll ever kill this engine from too much timing the way this particular TBV is functioning but I am intent on recovering the power I'm missing. Problem is we get the boat in the water only away from home and the reason for being there is get fishy hands - not greasy ones

                    [COLOR]#0000cd wrote:
                    Not following you on this one, unless you are refering to your curve as per what it shows below.

                    I could take almost any SBC Marine engine (others also), adjust out the progressive advance, load the engine enough to cause it to detonate and self destruct.

                    So don't underestimate how easily this can occur..... especially with a non-quench style SBC combustion chamber. [/COLOR]

                    [COLOR]#ff0000 wrote:
                    That's why I don't over advance engines like many do and I don't run engines wide open EXCEPT to check WOT for correct prop. With such retarded timing how could it ever detonate.



                    [/COLOR][COLOR]#006400 wrote:
                    Very unlikely that it would detonate....., but your numbers (if accurate) are certainly preventing it from developing any real power.

                    [/COLOR][COLOR]#ff0000 wrote:


                    I do understand that can destroy an engine in seconds. I know we're not extracting extracting maximum HP. We go there to relax and catch fish. A good day ends with fishy hands not greasy ones.

                    To reiterate we just recorded what the advance timing light displayed when the marks were lined by adjusting the controls on the advanced timing light. The module was enabled for all readings except when we set base. The ignition was turned off to disable the module for base and also to re-enable by removing ground. We recorded the RPM and advance from the display on the light.

                    It wasn't easy, the Admiral was at the controls calling and holding the RPM and I had my head stuck in the engine box. We also checkd the dash tach was close enough to the RPM display shown on timing light. We think we did a thorough and accurate job. If my base settings were confirmed by a very experienced mechanic then I would suggest my advanced timing light was properly used and is accurate enough for me. Thanks for your input.

                    [/COLOR][COLOR]#006400 wrote:
                    I know of only way to eliminate any possibility or error, and that would be to fully mark off your balancer......



                    ..... and then varify TDC.

                    (IMO, the PPS is the most accurate means for finding true TDC)

                    Then using a standard strobe light, strobe your timing marks at the various rpm, and jot them down.

                    Plot this out on graph paper. This will offer you "Real Degrees in Real Time".... with little risk of any Digital Timing Light electronic circuitry or algorythm errors, or possible user errors.

                    [/COLOR][COLOR]#ff0000 wrote:


                    [/COLOR]
                    OK.... you're up next... but I'm not sure which text color you should use for contrast!

                    Edit:

                    Terry.... I hope that we didn't loose you here! This has turned into a bit of a hi-jack!

                    Edit #2:

                    I see that this has been cropped from TerryW's "simple question - I hope" thread, and given it's own thread title.

                    That works for me.

                    .
                    Rick E. (aka RicardoMarine) 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

                    Please, no PMs. Ask your questions on forum.

                    Comment


                      #11
                      Bounty2850 - No need to use any more colours, I'm colourblind I was merely taking the time to respond to the answers you gave to clarify my points because I didn't agree with you on everything you said. As far as I'm concerned this has been stated and restated for clarification more than once.

                      As for hijacking, thanks for renamimg the thread. I don't have enough experience on this forum to know how to do all the fancy stuff. My technicolour attemp was all copy paste, took way too long- but while I was doing that some lightbulbs came from a combination of the information you provided and reading this stuff over so many times. That while carefully answering the points you made that I either did not understand or did not agree with. That's what healthy debate is - IMO. Again thanks for the insight you provided.

                      There have been quite few very engine literate people listen to this engine idling on a flush kit, idling in the water and also running under load. They all tell me it sounds really good doing all 3. An expert race car engine builders only comment was there was slight miss at idle on flush kit, when not completely warm, but that was gone the minute the throttle was opened - even very slightly. I couln't hear that.

                      New plugs, leads, distributor and coil come with the delco system so that should take care of that once it's installed. All part of the kit - except for the plugs

                      I would think it must running pretty good if it's set up to idle under load while trolling for several hours without a burp. I always said it runs and sounds great, ~ 100 hour compressions indicate it' a keeper too. BTW that's not our normal practise, we normally use a trolling engine. We got stuck out in bad weather over a low tide this year. The best thing to do was fish on main engine until the tide was high enough to get into our moorage. The Admiral was not happy but we landed a 36 lb Chinook Then the waters calmed........ and my hands got all fishy again.

                      I previously apologized to Terry if I had detracted from his original post but IMO my initial point was not a hijack. That being - it's not always that straight fwd when we migrate from 5.0 to 5.7L and if issues arise it can be more dificult because there is no standard curve with that much going on in that magical black box. Pardon me, I thought that info might be usefull to him.

                      I'm perfectly happy accepting the factory timing marks as accurate. IMO there is no need to re-invent that wheel. It is not a race engine. I'm also OK accepting the Timing Light manufactures instructions on how to use their advanced timing light- I don't have enough spare time to re-invent that wheel.

                      There are millions of these advance timing lights in use and Yes - they do rely on the factory marks being accurate enough and that the user has the ability to follow instructions to properly set the base with module disabled. Some love 'em and some hate them. I like 'em.

                      If I was to rebuild or have engine out of boat I would use a dial guage, be sure it's absolutely perfect and then degree the wheel for any future doubts. Realistically though I don't see that as being this issue.

                      I know the factory marks can be off if you want confirmation, to split degrees or need absolute pefection. IMO it's not worth it with engine installed if you weigh the pro's and cons. Once I understood the TBV better I quit challenging that because I could clearly see I wasn't even getting the typical advance curve for a SBC. Hence the ability to run extremely well with 15.5 x 15P but not with factory spec 19P prop on A1. Timing is the logical conclusion when you see the max achieved. I was looking for around 30* at 3K +.

                      I did not make up the functional explanations of the TBV module. That was accurately quoted from MC documentation for clarity. My point was that TBV is very smart when functioning correctly but can be anything but straight forward if it is not working as designed on the correct engine. Here's where your preferred setup would rule. I think someone said earlier that the TBV is how MC made a 220 hp engine into 260 hp.

                      I got lots of good information from the info you provided and I hope some got insight from the facts I provided. I've spent much time on this subject. You made no comments whether the 5.0 is less prone to detonation than the 5.7. I've often wondered why the 5.7 gets the added knock module to talk to the TBV module and the 5.0 does not.

                      BTW- Same goes for the carb - it's the same except it's not really ! Reason - the venturi. IMO that could have detrimental effect achieving WOT and detonation if advance is too agressive. To that end it got corrected by getting newish spare carb with correct venturi for a 5.7L. Original and never rebuilt. These are Mercarbs I refer to. I was happy with that change over and it was only 1/4 the cost of a new TBV module. Less than the cost of the venturi alone.....
                      2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

                      Comment


                        #12
                        nottingham88 wrote:
                        • 1 wrote:
                        • I'm perfectly happy accepting the factory timing marks as accurate. IMO there is no need to re-invent that wheel. It is not a race engine.
                        • I'm also OK accepting the Timing Light manufactures instructions on how to use their advanced timing light- I don't have enough spare time to re-invent that wheel.
                        • Once I understood the TBV better I quit challenging that because I could clearly see I wasn't even getting the typical advance curve for a SBC. Hence the ability to run extremely well with 15.5 x 15P but not with factory spec 19P prop on A1. Timing is the logical conclusion when you see the max achieved. I was looking for around 30* at 3K +.
                        • You made no comments whether the 5.0 is less prone to detonation than the 5.7. I've often wondered why the 5.7 gets the added knock module to talk to the TBV module and the 5.0 does not.



                        • 1 wrote:
                        • The original wheel was invented way back when the first SBC found it's way into a boat.

                          As for timing marks, the reason that we occasionally check TDC markings for true, is because some harmonic balancer out rings will slip on the inner rings, thus the TDC markings are no longer true.

                          However, this does not occur very often on a Marine engine.
                        • Agreed again. The original wheel was with the old school standard strobe type timing light. If there's a new wheel, it's the Digitally Advancing light.

                          If the digitally advancing timing light is a high end brand, it should work just fine.

                          But I'd sure steer clear of the Harbor Freight Chinese made quality units since this is so dang important... HP Race engine or Marine.... doesn't matter! In fact... Marine timing may be even more important, IMO.

                          One equipment algorithm error, or one user error, may cause trouble......., whereas seeing this in Real Time/Real Degrees removes any potential error from this.

                          Call me "old school" if you want to!
                        • Yes, and you should be looking for around 26* to 28* @ 3k+ rpm with this style combustion chamber.

                          Once we get into a quench build SBC, this can change some.
                        • Correct. I don't recall being asked.

                          That may be best answered by a factory Mercruiser Tech. Support person. One who is well educated in the TB advance curves.




                        Like said earlier, I have no dog in any fight here. I'm as curious as you may be regarding your advance numbers.

                        I've been looking at, playing with, changing, experimenting with, etc, SBC Ignition Avance numbers sine the 1960's.

                        I fully understand the perameters in which both HP Auto and Marine engines must operate within.

                        I also understand LPCP and what this means to torque and horse power, and how ignition advance affects this.

                        With that in mind, I'm still not able to make any sense from your low 18* @ 3k rpm.

                        Just for fun, http://"http://www.boatfix.com/merc/...in PDF format. I'm not able to find a V-8 engine ignition curve that suggests 18* BTDC @ 3k rpm.

                        Just to clarify.... I'm not trying to engage in any p!ssing match with you. Not at all!

                        If anything, I'm trying to help you with what appears to be an ignition advance that just doesn't sound right to me. I want for all us to have good running engines.

                        IMO, you either have a very rare performing SBC that uses Physics that are not of this world (like in Grits cooking analogy used in the movie My Cousin Vinny ), or your numbers are not accurate.

                        I just don't see how 18* BTDC @ 3k rpm can possibly produce any SBC Marine load torque.

                        In theory, that number may put your LPCP at approximately 10* later than hoped for.

                        Just a hunch..... but does that make sense?

                        .
                        Rick E. (aka RicardoMarine) 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

                        Please, no PMs. Ask your questions on forum.

                        Comment


                          #13
                          2850Bounty wrote:
                          • 1 wrote:
                          • The original wheel was invented way back when the first SBC found it's way into a boat.

                            As for timing marks, the reason that we occasionally check TDC markings for true, is because some harmonic balancer out rings will slip on the inner rings, thus the TDC markings are no longer true.

                            However, this does not occur very often on a Marine engine.
                          • Agreed again. The original wheel was with the old school standard strobe type timing light. If there's a new wheel, it's the Digitally Advancing light.

                            If the digitally advancing timing light is a high end brand, it should work just fine.

                            But I'd sure steer clear of the Harbor Freight Chinese made quality units since this is so dang important... HP Race engine or Marine.... doesn't matter! In fact... Marine timing may be even more important, IMO.

                            One equipment algorithm error, or one user error, may cause trouble......., whereas seeing this in Real Time/Real Degrees removes any potential error from this.

                            Call me "old school" if you want to!
                          • Yes, and you should be looking for around 26* to 28* @ 3k+ rpm with this style combustion chamber.

                            Once we get into a quench build SBC, this can change some.
                          • Correct. I don't recall being asked.

                            That may be best answered by a factory Mercruiser Tech. Support person. One who is well educated in the TB advance curves.




                          Like said earlier, I have no dog in any fight here. I'm as curious as you may be regarding your advance numbers.

                          I've been looking at, playing with, changing, experimenting with, etc, SBC Ignition Avance numbers sine the 1960's.

                          I fully understand the perameters in which both HP Auto and Marine engines must operate within.

                          I also understand LPCP and what this means to torque and horse power, and how ignition advance affects this.

                          With that in mind, I'm still not able to make any sense from your low 18* @ 3k rpm.

                          Just for fun, http://"http://www.boatfix.com/merc/...in PDF format. I'm not able to find a V-8 engine ignition curve that suggests 18* BTDC @ 3k rpm.

                          Just to clarify.... I'm not trying to engage in any p!ssing match with you. Not at all!

                          If anything, I'm trying to help you with what appears to be an ignition advance that just doesn't sound right to me. I want for all us to have good running engines.

                          IMO, you either have a very rare performing SBC that uses Physics that are not of this world (like in Grits cooking analogy used in the movie My Cousin Vinny ), or your numbers are not accurate.

                          I just don't see how 18* BTDC @ 3k rpm can possibly produce any SBC Marine load torque.

                          In theory, that number may put your LPCP at approximately 10* later than hoped for.

                          Just a hunch..... but does that make sense?

                          .
                          Bounty2850- I can assure you that both your help and willingness to share your knowledge is very much appreciated here. I think reading and re reading your answers has helped me come to some good ideas and conclusions.

                          The timing light in question; No it's not from Harbour Freight although I don't know what you'd call cheap. It is an Innova 3568+ which is patented in the good old USA, most likely made overseas but what isn't. $100- $150 retail. I always look for where it was designed not made. The build and method of plugging together for use is more than acceptable to me. The only comment I have was the diff between the snap on and the innova in bright sunlight. Snap on was better. Still 10* was 10* and I use it how often ?

                          Water test readings you say they're wrong. I agree 100% - but not because they were taken wrong They just show the problem.

                          It was not easy to HOLD certain RPM's long enough while I got the readings but they're all very close. I repeated when needed.

                          My records confirm that the prop used was a Vortex 4 blade 14.5D x 18P which by my estimations is roughly equivalent to

                          3 blade 14.5 x 19P. MAX RPM at WOT was 4K. WOT was 4100 if you prayed. Seriously over-propped with correct prop = missing HP.

                          Maybe there is something wrong with that module - or that during migration they created a wiring fault.

                          Since the TBV (Denso) unit is basically functional it was deemed overkill to split the original harness from the 5.0 to verify absolutely.

                          It's all plug and pray stuff- normally either works or doesn't UNLESS it's a module that works for some functions and not for others as in malfunctioning or partially working.

                          I know it uses an internal rev counter but nowhere can I find the logic it runs on other than counting RPMS and comparing to before and after functional adjustments under its own logic or control of the anti knock module.

                          It also has engine sensors which I think are just switches for Oil Press, EngineTemp and Drive Oil. If I had a functional explanation for the innards of the Denso unit life would be great. I'm sure denso does their best to protect these units. I would not be surprised however to find someone did or has done something to harm this unit.

                          I have seen 4600 RPM on 2 separate occcasions both running 17P and it went there quickly and without hesitation and I throttled back immediately since still quite new. I have since tried many times , with more hours, on a warm engine and flat water. 4K with 19P.

                          IMO no harm has been done continuing to use the boat with such retarded timing. The timing must be the main reason I shouldn't use the 19P prop. I actually prefer to be slightly underpropped vs overpropped for engine longivity. I did record compression readings after 10 hours run time. 2 @ 160 and 6 @170 psi with my guage. Properly done. Not repeated since.

                          At that time I removed unidentified platinum plugs and replaced with those id'd from valve cover or manual. The ones removed were from the 5.0L. Once ID'd I may re-use them - they're as new except slightly pink tips. I've heard incorrect plugs can do harm, besides affect performance and pink indicate overlean conditions ? AC 41-932 with 25328284 below. Any info on those ?

                          I looked at the link you sent and see the TBV at end of document page 4B-16. That graph and the next few pages (not shown at link) do a pretty good job explaining the AUTO functions of TBV - that missing part is what I inserted into the techinicolor answers previously.

                          The previous pages 4B 11 and 4B 13 specifically show TB IV but do compare the 5.0 and the 5.7 L. Not sure if those would be vortec versions or not and what relevance that may have. I think they could be vortec with TB IV.

                          I was looking at the total advance numbers - they do provide min and max numbers. The base timing may differ by 2 * but I'm looking for a whole lot more than that !

                          4B -13 shows 5.7 mag alpha advance curve max - 26* and Min 23 * - plus of course the base of 8* - far exceeds mine around the critical ~3K range. I assume TB IV not V

                          4B-11 shows a 5.0 with TB IV again the min 20 + 8 or max 23 + 8*. I do like specific specs. Once again those numbers jive with what we'd reasonably expect.

                          IMO those references remove all doubt that when I achieve even close to the correct range TA around the 3K mark I will need to change the prop back up closer to where it should be. I'm still hopefull.

                          The options list for 2003 2359 clearly shows the stock prop as 14.5 x 19P and the info for the 5.0 base engine clearly shows the stock prop as 15 x 17P. Why would I doubt that with sensible load for that purpose. I know all props are different but you have to start somewhere.

                          I'll post the info I dug up on the "Delco Voyager distributor is a fully self-contained marine ignition system." it goes on to say. Installation is not difficult, but the timing setup must be exact.

                          Their chart of included engines has from 3.0L to 8.2 L but for the 5.0 and 5.7 initial is always 8* or 10 * with reference to fuel grade used - 87 or 89.

                          A comment quoted from their instructions just after the timing shunt has been removed

                          Quote "Check total timing at 2000, 3000 or 4000. (For example, a 5.7L Vortec engine , total timing will be 26 * or 28 * depending on your initial timing.)" End quote

                          To me that means properly set the delco system would achieve 28* total timing with my 10 * base setting. Isn't that what you've advised would be safe and around min to get some of the ooomph the 5.7 has ? It sounds so much better than the dismal numbers I'm getting.

                          I might then be losing some HP from lack a few more degrees during optimum conditions if the TBV was working properly BUT it will be a huge step in the right direction and to myself not objectionable with the unknown piston tops and combustion chambers.

                          Normally during a major change I like to prove the removed parts defective and I think that's whats been hanging this up.

                          X2 if parts are not cheap. x3 if I'm not sure if the 5.0 module should be used on 5.7 without knock sensor.

                          I'm not even sure if the coil is weak but doubt it. Don't see how that could produce these timing numbers.

                          To that end I bought the delco stuff, avoided installing because it's just more work and boat runs good, has been very reliable and it's hard to convince most something is not right with it. Obviously the advance curve was studied because thats the most likely source of this problem. Installing the delco may have moved up the list of importance though...........

                          Thanks for the ideas towards completing my search for the missing horse ponies. They are available if I can just get them out
                          2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

                          Comment


                            #14
                            nottingham88 wrote:
                            • 1 wrote:
                            • Water test readings you say they're wrong. I agree 100% - but not because they were taken wrong They just show the problem.
                            • Their chart of included engines has from 3.0L to 8.2 L but for the 5.0 and 5.7 initial is always 8* or 10*
                            • To me that means properly set the delco system would achieve 28* total timing with my 10 * base setting. Isn't that what you've advised would be safe and around min to get some of the ooomph the 5.7 has ? It sounds so much better than the dismal numbers I'm getting.
                            • I'm not even sure if the coil is weak but doubt it. Don't see how that could produce these timing numbers.
                            • Thanks for the ideas towards completing my search for the missing horse ponies. They are available if I can just get them out



                            • 1 wrote:
                            • Under any other circumstances I would normally agree that your numbers indicate a problem........ but why does it run well?

                              On one hand you say that the engine runs strong...... and yet on the other hand your numbers appear to be dismal numbers, as you put it.

                              As I've suggested, I just can't see or understand how a GM SBC 5.7L engine in a Marine application is going to produce any mid RPM performance while seeing only 18* of spark lead @ 3k rpm.

                              It just doesn't make sense to me.

                              IMO, either the numbers are inaccurate, or physics of another world apply to your engine! :kidding
                            • It may be 8* or 10*, but keep in mind that these aren't necessarily written in stone. A dynamic check will let you know.

                              If it needs to be 8* to achieve TA, then 8* it is.

                              If it needs to be held back to 7* to achieve TA, then 7* it is, and so on, etc.
                            • Yes, I probably offered a range, but I try to avoid quoting TA numbers to anyone unless it can be shown via an OEM curve graph.

                              Vortec or not, your later model engine is very likey fitted with the full dished pistons. IMO, 30* BTDC at/near 3k rpm for this engine build would be pushing it, perhaps putting it near the edge of Detonation. It may be fine, but I'd not exceed this!

                              I can't answer the part about the Delco advance. Perhaps Delco can tell you, or you just install it and then check your timing advance dynamically.
                            • Agree..... I don't see how a coil would cause a change to the advance.
                            • I doubt that they ran too far away with those good 160-170 psi cylinder pressure readings.

                              Keep looking..... you'll find them!




                            This one is an afterthought, and is not necessarily in order.

                            nottingham88 wrote:
                            4B -13 shows 5.7 mag alpha advance curve max - 26* and Min 23 * - plus of course the base of 8* - far exceeds mine around the critical ~3K range. I assume TB IV not V
                            While this spec may look aggressive, look at the RPM where the Max and Min are shown.

                            First.... we don't typically operate at this RPM, so I'd be looking at/near the 3k rpm scale.

                            Secondly..... Detonation potential is perhaps greater at/near 3k rpm than it is at/near 4.8k rpm.

                            I'm not suggesting that detonation cannot occur at 4.8k rpm, just say'n.

                            If I was trouble-shooting this, I'd install a degree decal onto the harmonic balancer, or mark off the balancer by other means.

                            This should give me up to 35* -40* to work with.

                            I'd then take the timing light out of digiatal mode, and use the standard mode.

                            This would allow me to see the progressive advance in Real Time and Real Degrees.

                            As suggested, when strobing dynamically in standard mode, we can't help but see actual advance.... in other words, BASE advance will be included in what we see. Or as you put it..... WYSIWYG.

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

                            Other than marking off the balancer and then strobing in standard mode, replacing the Merc TB module, or trying the Delco EST ignition system, I'm out of suggestions.

                            .
                            Rick E. (aka RicardoMarine) 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

                            Please, no PMs. Ask your questions on forum.

                            Comment


                              #15
                              Bounty2850, My definition of running and sounding good probably differs from yours and for good reasons on both parts.

                              On your part you are an accomplished marine mechanic from what I've read as well as an avid boater.

                              On my part I define a good running boat like this; starts every time, gets me there and back every time, has good oil pressure, doesn't overheat or rattle and so on. It just sounds smooth.

                              I will get around to installing the Delco Voyager ignition. You can be sure I'll be taking note of the TA curve after, and whether performance is up or down.

                              If I could degree the wheel in location I would, but I can't. I can still see the advance working with the light as throttle increases but a degreed wheel makes life easier I agree. I'm also not quite as flexible as I was.

                              Delco Voyager would be max 28* TA. Even around 3K I would think that should be OK and if not an initial of 8* instead of 10* should remove all doubt giving 26* TA. I don't think thats pushing the limits with 89 marine fuel.
                              2003 Trophy Pro 2359; Rebuilt 5.7L Vortec longblock (crate) using rest of the previous owners freeze destroyed 5.0L. Now fully FWC Alpha 1 Gen 2 drive.

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