Performance timing

Electrical and Ignition

  1. dazedand confused

    dazedand confused Well-Known Member

    Messages:
    155
    Likes Received:
    35
    Joined:
    Oct 3, 2010
    Location:
    hollister mo.
    Local Time:
    1:28 PM
    AJ/FormS

    I have a push on chrome breather on the passenger side valve cover and a pcv valve on the drivers side. Do i need to get rid of the pcv and put on another push on breather? Also my 727 has a stock torque converter . My truck has power brakes. Do you think ill have to drill those holes on thebutter flies on the 600 eddie i have on the engine? If i remember after i put 500 miles on the new 318 i did a compression test with it warmed up and plugs out coil wire disconnected and 4 barrel wide open and i think it was 130 psi per cylinder . I let it crank 4-6 times each cylinder
     
  2. yellow rose

    yellow rose Master Of Insanity

    Messages:
    24,493
    Likes Received:
    20485
    Joined:
    Jun 19, 2015
    Location:
    Walking a crooked mile
    Local Time:
    11:28 AM

    Leave the PCV system on it.

    I'm not sure why you'd need to drill the butterflies if you can get the engine to idle at the correct RPM without the idle screw being all the way in.

    You need to read some more about the difference between intitial and total timing so you understand it. Like mentioned above, some of the MP distributors have a pretty quick curve in them, meaning you'll get the total timing in too soon. I'm all for a relatively quick curve, but you have to manage advance so you don't get rattle on tip in. And if you can, you need to run the vacuum advance. That distributor SHOULD have an adjustable vacuum can on it so you can at least control how much vacuum advance you have.

    You may want to find a local guy to put your distributor machine so you can get an accurate look at what the curve really looks like.
     
    • Agree Agree x 1
    • dazedand confused

      dazedand confused Well-Known Member

      Messages:
      155
      Likes Received:
      35
      Joined:
      Oct 3, 2010
      Location:
      hollister mo.
      Local Time:
      1:28 PM
      Ok ill try to study up on the total and initial timing. Should i switch back to a stock distributor?
       
    • yellow rose

      yellow rose Master Of Insanity

      Messages:
      24,493
      Likes Received:
      20485
      Joined:
      Jun 19, 2015
      Location:
      Walking a crooked mile
      Local Time:
      11:28 AM

      Nope. What you have is just fine.

      You should take up 512 on his offer. He's a good guy (bought from him on this very forum and he's as straight as the day is long) and you'll probably pick up this stuff much easier if you have some help.

      I was lucky. When I was growing up, my dad had a distributor machine. So at 12-13 years old I was doing advance work and such. Sadly, when I was 14 he sold it. He is still kicking himself in the can for that all these years later.

      I finally bought my own and its now up and running. You can do much more with the machine much quicker. But 512 could definitely get you going and shorten up your learning curve.
       
      • Agree Agree x 1
      • Mattax

        Mattax Just the facts, ma'am FABO Gold Member

        Messages:
        11,151
        Likes Received:
        7040
        Joined:
        Feb 7, 2013
        Location:
        Phila. Pa
        Local Time:
        2:28 PM
        I've posted a chart from the Direct Connection Bulletin as well as graphs of what I measured. Tach drive distributors are super fast in. Work great for the drag strip, and easy starting for high comp engine with a manual transmission.
        Yup. That's for the one for tach drive distributors.

        OP has a regular MP one (with vac advance, no tach drive) or a copy. If its a copy then who knows what's in it. Only way to be sure will be make some timing - rpm measurements,

        Maybe. But probably the curve will be further from ideal since the engine combustion characteristics are now rather different than a stock 2 bbl 318 would have had.

        Initial or base timing: Timing at an rpm with no advance added.
        Normally on a stock engine timing at idle is the baseline. Idle is usually 500 - 650 rpm (pre-smog), or 600 - 700 rpm smog era.
        Hot rodded and race engines requires some trial and error tuning to get the idle speeds down anywhere close to 700 rpm.
        When you are measuring timing at idle it is critical to note the rpm. Timing at 800 or 900 rpm will likely be base timing plus some advance unless the spring tension is increased. Don't worry about it. Just write down the rpm.

        Mechanical Advance: Degrees added by the distributor's weights moving outward with rpm. Usually just called advance.

        Total Timing: Initial timing plus the maximum mechanical advance. With hot rods and race engines, sometimes the idle timing is very unstable, especially early in the tuning process. For that reason, a high rpm timing measurement is a better reference. For example, mopar performance instructions suggest measuring at 2800 rpm.

        Purpose:
        upload_2020-1-3_10-43-26.png

        Mechanical or Centrifical Advance

        Compensates for the reduced amount of time (miliseconds) available for the burn as rpm increases. Its not directly proportional because engine efficiency decreases burn time as rpms climb. A 'low performance' 318 usually has good lower rpm efficiency, but does not gain as much efficiency with increasing rpm. A 'high performance engine' is usually the opossite.

        Vacuum Advance:
        upload_2020-1-3_10-49-52.png
         
      • AJ/FormS

        AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

        Messages:
        19,189
        Likes Received:
        7088
        Joined:
        Jan 19, 2014
        Location:
        South-Central Manitoba,Canada, 900ftelevation
        Local Time:
        1:28 PM
        The 292/292 is a pretty big cam, and in a modest 318 even bigger. That means, with the Transfers sync'd, the timing will be modest, and the idle vacuum pretty low... which means the PCV will not be flowing much. But it is your principal Idle-air bypass. So leave in in there.
        Don't forget that at WOT, there is no way for the PCV to keep up, so the breather part of the system will work in reverse, spewing crankcase vapors all over your valve cover; this is normal whenever the engine is under heavy load, not just at WOT. If you are not returning these vapors to the air-cleaner housing then you probably want to reroute them somewhere else.
        If your carb has a 4-corner idle system, then you may be able to get away with cracking the secondaries, to supply the engine's craving for air. Then you won't or may not need, to drill the primaries. Some guys believe drilling the primaries is a bogus thing to do. Not me, I do whatever it takes, usually as cheaply as possible. I have never had success with introducing dry air into the secondaries; ie, cracking them. You can make it work, but it will not idle properly; try it for yourself if you like. IMO this is as bad or worse, than hooking the brake-booster to the #8 runner. If you don't like the idea of drilling holes; there is an adjustable PCV system on the market, that can be used to good effect. Say Goodbye to about $160 IIRC. The engine doesn't care where it gets the required air, so long as it exits into the airstream with the low-speed fuel,lol.
        Sorry no pics. When you flip the carb upside down, you will see the transfer slots in the front sides of the throttle bores. And you will see the idle mixture ports close by, with the screw-tips slightly (or not) protruding into the bores. You just need to be in the general vicinity of those slots and ports, and not too close to the edge; that is all. If you manage to get them the same between the bores, it looks good on your resume.... that is all,lol.
        As an aside; when I got this right, I was able to idle the engine down to 550rpm, in first gear, and that big 292/108 pulled my pig-Barracuda around on hard,flat, level ground. However, at 11.3Scr the pressure pulses were so strong that with a manual trans, the car would start to buck like a wild horse. I reduced the idle-timing to 5*( from 14*) , and that went away, as long as the rpm was above 550 in gear. But,lol, at this setting it would not climb the slightest hill with a starter gear of 3.55x2.66. So I got me a Commando-box with it's 3.09 low-gear for a TM improvement of 16%, and then I was happy, because this got me down to 4 mph. It would operate like that for as long as I needed it to.
         
      • AJ/FormS

        AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

        Messages:
        19,189
        Likes Received:
        7088
        Joined:
        Jan 19, 2014
        Location:
        South-Central Manitoba,Canada, 900ftelevation
        Local Time:
        1:28 PM
        That stock TC is gonna kill your performance with a 292/292/112 cam and 9.1Scr.
        If your combo is already assembled, Try to leave that TC in there for a week or so. By that time you will have a pretty good idea of when,where, and how badly it sux. And better, you will have a good idea where the power is, and what stall-rpm to order up. This will vary somewhat with your rear gear. With a 9.1Scr 318, I predict that you will need at least 3.91s and at least a 3200TC for a streeter.
        Forget fuel economy, just furgetabowdit. With just 98* of power extraction, just 106* of compression, and a fairly hefty effective overlap of 60*, Plus cylinder pressure down around 125psi, there is almost nothing you can do to improve it's fuel economy........ but I suspect you knew that going in,lol.
        In my 367 that cam did not come alive until 5200, and the 108 version I had, just rocked to deep into the 6000s! I shifted it at 7000plus which, with my trans, allowed the rpm to drop back to 5000 ........ "perfect" in my combo.
         
        Last edited: Jan 3, 2020
      • AJ/FormS

        AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

        Messages:
        19,189
        Likes Received:
        7088
        Joined:
        Jan 19, 2014
        Location:
        South-Central Manitoba,Canada, 900ftelevation
        Local Time:
        1:28 PM
        Depending on the booster, not all of them will work properly with the 292 cam's very low idle-vacuum. On my combo I always drove it into my parking stall .Later, by the time the engine was warmed up, and I had blipped the throttle a few times, she had enough vacuum to work my brakes. And with a manual trans, I am always blipping and speed matching on the slow-down, so the booster is always charged. I used a booster off a mid-70s F-car.... I think. That or a 73 Dart. For my combo, it always worked.
        It's been said that the 292 with an automatic, will not keep itself charged all the time. I guess you will know soon enough.
        I can tell you for sure that the Dual diaphragm booster did not work for me. I even went so far as to take it apart and see if I could mod it, but no dice. Cuz I really liked it's small compact size and original look. Now it sits on the shelf with all it's also-ran brethren.
         
      • famous bob

        famous bob mopar misfit

        Messages:
        17,532
        Likes Received:
        7018
        Joined:
        Aug 14, 2011
        Location:
        okla
        Local Time:
        1:28 PM
        Off topic a little , but , have any if u guys ever ran a pcv on one side and a pan evac on the other side, in a hi flowing street exh. system ? such as a dual 3 1/2'' system w/ bullet mufflers , dumped ?
         
      • yellow rose

        yellow rose Master Of Insanity

        Messages:
        24,493
        Likes Received:
        20485
        Joined:
        Jun 19, 2015
        Location:
        Walking a crooked mile
        Local Time:
        11:28 AM

        I run both. And I pull the pan evacs from both sides.
         
      • famous bob

        famous bob mopar misfit

        Messages:
        17,532
        Likes Received:
        7018
        Joined:
        Aug 14, 2011
        Location:
        okla
        Local Time:
        1:28 PM
        On a street car? Been thinking of hooking a pan evac up on the breather side .
         
      • AJ/FormS

        AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

        Messages:
        19,189
        Likes Received:
        7088
        Joined:
        Jan 19, 2014
        Location:
        South-Central Manitoba,Canada, 900ftelevation
        Local Time:
        1:28 PM
        I ran pan E-vacs on my 367 streeter ,yes with a PCV. But not for long.
        I also run a HV pump, and increased oiling to the top-end. Well the P-side E-vac found that right away; only took a few corners and such, the way I drive. I have 1.6 aluminum rockers and cast M/T covers. I modded the baffles and put some open cell foam in there for a test run, but that only delayed the onset of oiling the mufflers. I ain't drying up my top end any time soon, so , off they came.
        It took a really long time to cook that oil out of the mufflers. I could fabb something up but ..... there's not much point, IMO, for 5 second zero to 60 blasts. They did work really well tho, while they were on there.
         
      • yellow rose

        yellow rose Master Of Insanity

        Messages:
        24,493
        Likes Received:
        20485
        Joined:
        Jun 19, 2015
        Location:
        Walking a crooked mile
        Local Time:
        11:28 AM

        Yes. And I use an M. E. Wagner PCV valve.
         
      • dazedand confused

        dazedand confused Well-Known Member

        Messages:
        155
        Likes Received:
        35
        Joined:
        Oct 3, 2010
        Location:
        hollister mo.
        Local Time:
        1:28 PM
        I have 3:55 gears in the 8.25 rear
         
      • RustyRatRod

        RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

        Messages:
        64,481
        Likes Received:
        37444
        Joined:
        Jun 7, 2010
        Location:
        Georgia
        Local Time:
        2:28 PM
        You have a stand up and very knowledgeable member on here who has offered to help. You are mentally incapacitated if you do not take him up on it. You will meet a new friend and learn something at the same time and get your timing sorted out. What's not to love?
         
        • Agree Agree x 1
        • dazedand confused

          dazedand confused Well-Known Member

          Messages:
          155
          Likes Received:
          35
          Joined:
          Oct 3, 2010
          Location:
          hollister mo.
          Local Time:
          1:28 PM
          Rustyratrod I appreciate everyone's help on here but can't visit 512 Stroker in person . I work and we both live in opposite ends of missouri north and south . I live in hollister just a couple miles south of branson and he live up in lake of the ozark up by Jefferson city mo. Other wise i'd pay him a visit.
           
          Last edited: Jan 4, 2020
        • crackedback

          crackedback FABO Gold Member FABO Gold Member

          Messages:
          18,707
          Likes Received:
          3030
          Joined:
          Aug 7, 2005
          Location:
          92201
          Local Time:
          11:28 AM
          Timing is like bulding a house. Build a house on a crappy foundation and your results will be subpar.

          Timing is the same with initial being the foundation. Get that right and other things in the tune up come around. Even though the tq 20 has a bunch of advertised duration, it's not like the 292 mopar cam. My guess is that you will end up somewhere in the 14-18 range for initial and 34ish for total. Vacuum adavance will add to the cruise total. One big clue that you don't have enough initial, besides the stinky idle, is RPM drop when pulled into gear. Drop should be no more than about 100-150 rpm. Anything more and the engine isn't likely happy or the converter is WAY too tight on an auto car.

          Simple test, start engine get it warmed up, Give the distributor a smidge of a twist CCW. If the engine picks up rpm, it wants the timing at idle.
           
          • Agree Agree x 1
          • dazedand confused

            dazedand confused Well-Known Member

            Messages:
            155
            Likes Received:
            35
            Joined:
            Oct 3, 2010
            Location:
            hollister mo.
            Local Time:
            1:28 PM
            Crackedback
            Is that 34 total timing? And at what rpm ? You said to hook up the vaccum port but what port on the carb ? Full vaccum or the port for timed vaccum? And after the vaccum is hooked back up what should the timing be ?
             
          • RustyRatRod

            RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

            Messages:
            64,481
            Likes Received:
            37444
            Joined:
            Jun 7, 2010
            Location:
            Georgia
            Local Time:
            2:28 PM
            "All of that" is combo dependent. There is no one set formula for timing. DO what we've told you with what you have and you can find where your initial wants to be right now. Just bump the timing up 2* at the time, until the engine does not raise in RPM anymore. Each time you bump the timing up, bring the idle back down on your tach or tune up gauge to where it's supposed to be. 700 is a good place. Once you get to where the engine does not idle up when the timing is advanced that last 2*, then back it back down that last 2* and take the reading with your timing light. WRITE IT DOWN, because until you can limit your total timing, you do not want to leave it there, because it will have too much total timing. Then back it back down to where it was before and it will be safe until you can get the total timing limited to around 34 "or so" degrees.
             
            • Like Like x 1
            • RustyRatRod

              RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

              Messages:
              64,481
              Likes Received:
              37444
              Joined:
              Jun 7, 2010
              Location:
              Georgia
              Local Time:
              2:28 PM
              That's a shame. I would endeavor to make that happen.
               
              • Agree Agree x 2
              • crackedback

                crackedback FABO Gold Member FABO Gold Member

                Messages:
                18,707
                Likes Received:
                3030
                Joined:
                Aug 7, 2005
                Location:
                92201
                Local Time:
                11:28 AM
                What RPM... when it's DONE advancing. ANYONE that tells you to set total timing at a certain RPM has no idea what is actually in the curve for springs. See that "it kept advancing to 4600..." comment. That's the issue there.

                I NEVER said hook up the vacuum advance. Just that after you are done with the first two pieces, the vacuum advance will add at cruise. All this tune up stuff should be done with the vac can disconnected and the port at carb plugged.

                I run it on ported and the can SHOULD NOT be active at idle... PERIOD!!!

                Set initial FIRST, then get the total adjusted/limited, then worry about vac advance. One STEP at a time. The engine will TELL you where it's happy.
                 
                • Agree Agree x 2
                • 67Dart273

                  67Dart273 FABO Gold Member FABO Gold Member

                  Messages:
                  45,017
                  Likes Received:
                  12611
                  Joined:
                  Oct 14, 2010
                  Location:
                  Idaho
                  Local Time:
                  11:28 AM
                  ^^What he said..........and if you are squeemish about blipping the throttle with all that hardware thrashing around, then check the timing with the engine not fully warm, and temporarily unhook the fan belt just long enough to set and check the high RPM timing. then point the light down there, get "the picture" and blip the throttle to make sure it IS THE END of the advance
                   
                • Mattax

                  Mattax Just the facts, ma'am FABO Gold Member

                  Messages:
                  11,151
                  Likes Received:
                  7040
                  Joined:
                  Feb 7, 2013
                  Location:
                  Phila. Pa
                  Local Time:
                  2:28 PM
                  Steps:
                  1. Review the definitions in post #30.

                  2. Have a notepad, your timing light, and tachometer ready. If you have a vacuum gage, connect it to a manifold vac source. If you don't, don't worry about it right now.

                  3a. Disconnect the hose from the vacuum advance canister on the distributor. Plug the hose with a golf tee or similar; or remove the hose and cap the vacuum source. This is always done, even when setting to factory specs on a stock engine. See definations of timing for why.

                  3b. Put inductive clamp for timing light on #1 spark plug wire. Route the timing light wires so they will not contact the exhaust manifolds or fan blade when the light is being used as well as where ever you are laying it down. Connect the tach with same precautions.

                  4. Start engine and get it running at a stable speed.

                  5a. Aim timing light at the timing tab/fixed marks on the timing cover.
                  5b. With light set at 0 on the dial, note the timing mark lit by the strobe. Read that and then read the tachometer. Write both down.
                  5b alternative. If the strobe is not illuminating the zero mark on the damper where it lines up with a fixed mark, then increase the dial setting on the timing light until the mark on the damper lines up with the TDC mark on the timing cover. Read the number on the dialback light. Check the tachometer. Write rpm and advance.

                  6. Repeat at slow idle. If equiped with an automatic transmission, and you can do so safely (a second person is best), repeat at slow idle with transmissoin in gear. Also read and write down the vacuum with this reading.

                  7. In neutral or park, read the tach, the timing and rpm again. Write these down. Increase the engine speed 200 or 250 rpm and repeat. Do so again and again every 250 or 500 rpm whatever you feel is sufficient for your purpose and comfort level. At higher rpms you will have to use 5b alternative. At some point you can just do as 67Dart273 suggested - quickly snap the throttle to 4000 rpm or so and see what the timing is. And if you are not comfortable doing that yet, that's OK too. As with crackedback explained, its important to get foundation built first.

                  8. Return engine speed to the same as you wrote down at the begining of step 7.

                  9. If you want to recheck if the engine will now idle even lower since the engine is warmer, this is a good time to do so. Check to see if the timing is lower at the new lowest rpm the engine will idle. Write down the timing, rpm and vacuum. See if it will idle in drive. If not, increase idle speed to where it was when it did.
                   
                • dazedand confused

                  dazedand confused Well-Known Member

                  Messages:
                  155
                  Likes Received:
                  35
                  Joined:
                  Oct 3, 2010
                  Location:
                  hollister mo.
                  Local Time:
                  1:28 PM
                  Mattax posting#48

                  I followed the instructions after engine fully warmed up and running 92 octane no ethanol fuel psi 6 and vaccum gauge reading 18-1/2 steady not fluxuating! Idle in park 1000 rpm and vaccum port on distributor plugged off
                  Time light on 0 on dial and timing reads 30º at the 0 mark on timing cover tab.

                  In drive tach at 600 rpm and timing reads 24 º and in neutral tach reads 900 rpm timing reads 25 added 250 rpm's = 34º at the 0 mark on timing cover.

                  Snapped the throttle to 3000 rpm timing reads: 44º give or take a degree?
                   
                • dazedand confused

                  dazedand confused Well-Known Member

                  Messages:
                  155
                  Likes Received:
                  35
                  Joined:
                  Oct 3, 2010
                  Location:
                  hollister mo.
                  Local Time:
                  1:28 PM
                  512Stroker was that idle suppost to be in park or drive? Right now in park my engine idles at 1000 rpm and in drive it idles at 600-650 rpm
                   
                1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                  By continuing to use this site, you are consenting to our use of cookies.