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"Correct" timing marks don't work..

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  • Ignition: "Correct" timing marks don't work..

    Every year or so I embark on a failed mission to "correctly" tune and time my R2 Hawk. When I have everything set correctly according to the timing marks (12* initial, full advance comes in at about 2400 rpm, 32* BTDC on the mark, according to my non-dial back timing light), car just lacks power. I always end up adding another 12-14 degrees of distributor advance which is where it likes to run and is about 10* cooler, still starts fine. I tune it to the generally available premium pump gas junk and never get any ping or detonation, been tuning it that way for over 10 years now without issue. My question is, is that typical for R2 timing? Engine is .030 over, b&b with Erb pistons and R2+ cam with a calculated 9 1/2 :1 cr, Pertronix igniter, locked distributor, MSD 6AL, MSD 8981 timing computer, R3 headers and Erb supercharger and was built by a very reputable shop. 44-46* seems like a lot of advance for this motor but I have double checked it and I'm pretty sure my old school timing light doesn't lie.

  • #2
    On my Super Lark damper there is only one demarcation mark and it lines up only with the pointer mark at TDC #1 piston. The cam is bleeding off some of the "on paper compression prediction." The only true compression is dynamic compression values. The lower this value the more timing the engine can tolerate.

    What is the cranking compression on WOT and all 7 plugs installed?
    Start and Stage Your Studebakers

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    • #3
      Originally posted by 11SecAvanti View Post
      On my Super Lark damper there is only one demarcation mark and it lines up only with the pointer mark at TDC #1 piston. The cam is bleeding off some of the "on paper compression prediction." The only true compression is dynamic compression values. The lower this value the more timing the engine can tolerate.

      What is the cranking compression on WOT and all 7 plugs installed?
      Curious... why would it make a difference to check compression plugs in or plugs out?
      sals54

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      • #4
        Originally posted by 11SecAvanti View Post
        On my Super Lark damper there is only one demarcation mark and it lines up only with the pointer mark at TDC #1 piston. The cam is bleeding off some of the "on paper compression prediction." The only true compression is dynamic compression values. The lower this value the more timing the engine can tolerate.

        What is the cranking compression on WOT and all 7 plugs installed?
        Haven't tried that, sounds easy enough to do. How would I interperet the results? I don't race this car, I just like to drive it like it was supposed to be driven-and surprise a few young'uns now and then...
        This builder fixes a groove at TDC, mfgr's recommended full in advance and 3 grooves at 1/4 revolution points for easy valve lash adjustments.
        Last edited by 63 R2 Hawk; 11-06-2017, 05:10 PM.

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        • #5
          The cranking compression will vary to the starter rpm. With the plugs removed the starter spins faster and gives a higher compression reading. For a baseline I stay with 7 plugs in and carb WOT. Worn rings also give lower psi readings vs a 1 to 3% leakdown tested cylinder. Leaky valves, cam overlap, valve settings, starter rpm, engine at operating temperature vs cold engine, etc. are Some of the influcing factors involved in a compression gauge test.

          But again, if the compression is say 130 psi vs say 175-180, then the lower compression needs and will accept more timing advance. Both static and total mechanical advance. As long as the octane is good and no detonation or preignition exists.
          Start and Stage Your Studebakers

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          • #6
            If it cranks hot and dont ping quit worrying and drive it!!! not all mechanical problems can be sorted or explained, enjoy it and save your hair. Luck Doofus

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            • #7
              Most of the harmonic balancers in service were made 50+ years ago and the rubber bisquit between the balancer hub and weight deteriorates over the years and can allow the weight to move or slip causing the timing mark to move which makes it nearly impossible to set the timing correctly. There is something seriously wrong if you have to add 12 or 14 degrees of extra timing to get the engine to make good power. I recommend pulling the #1 plug and getting the piston as close to TDC on the compression stroke as you can and check the location of the timing marks. Bud

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              • #8
                Probably a dumb question but if the distributor were a tooth off, would that cause the issue?

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                • #9
                  With all older vehicles, I adjust the timing by listening to the engine when under load.
                  I keep advancing the ignition until I hear SLIGHT pinging (pre ignition), then
                  back the timing off until ALL detonation is gone!

                  Comment


                  • #10
                    Originally posted by Jiles View Post
                    With all older vehicles, I adjust the timing by listening to the engine when under load.
                    I keep advancing the ignition until I hear SLIGHT pinging (pre ignition), then
                    back the timing off until ALL detonation is gone!
                    Yes, agree, that's a good procedure for standard engines.

                    No, an R2 can melt itself before some old ears among us would detect that SLIGHT pinging.

                    Yes, agree, the timing marks are questionable, as 46 degrees is way to much initial plus centrifugal advance. Having said that, if vacuum advance is somehow being added in, the engine will cruise just fine at 46 degrees total if that 12 degrees of vacuum drops out when boost comes up.

                    Probably a dumb question but if the distributor were a tooth off, would that cause the issue?
                    The timing light indicates when the spark for that cylinder occurs, regardless of where the distributor is installed. One tooth off and on R2 engines, it might run, but the timing would be so advanced or retarded the timing mark might not be visible when the timing light flashed.

                    jack vines
                    PackardV8

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                    • #11
                      Originally posted by Jiles View Post
                      With all older vehicles, I adjust the timing by listening to the engine when under load.
                      I keep advancing the ignition until I hear SLIGHT pinging (pre ignition), then
                      back the timing off until ALL detonation is gone!
                      Never added a knock sensor, but this might be worth considering.
                      http://www.ifsja.org/forums/vb/showthread.php?t=34984

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                      • #12
                        Originally posted by Bud View Post
                        Most of the harmonic balancers in service were made 50+ years ago and the rubber bisquit between the balancer hub and weight deteriorates over the years and can allow the weight to move or slip causing the timing mark to move which makes it nearly impossible to set the timing correctly. There is something seriously wrong if you have to add 12 or 14 degrees of extra timing to get the engine to make good power. I recommend pulling the #1 plug and getting the piston as close to TDC on the compression stroke as you can and check the location of the timing marks. Bud
                        Thanks for the idea. Harmonic balancer was 6 years old when I bought the car and I still had the issue then. I recently checked it and it is still in good condition, rubber is solid.

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                        • #13
                          Originally posted by jeryst View Post
                          Probably a dumb question but if the distributor were a tooth off, would that cause the issue?
                          I haven't checked rotor phasing, but your question got me to thinking about a related possibility. As mentioned, I am running a locked distributor (no vacuum or centrifugal timing compensation), but I don't recall ever checking to see if it is locked in the correct rotor phase position. Could be, the rotor is locked in the wrong position. Time to do some research....and pull the distributor, something I have been avoiding....

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                          • #14
                            That is interesting. What is the advantage of no timing advance mechanisms in the distributor? Do you have something somewhere else in the engine that will advance timing as needed?
                            RadioRoy, specializing in AM/FM conversions with auxiliary inputs for iPod/satellite/CD player. In the old car radio business since 1985.

                            17A-S2 - 50 Commander convertible
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                            5H-D5 - 54 Commander Conestoga wagon
                            56B-D4 - 56 Commander station wagon
                            60V-L6 - 60 Lark convertible

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                            • #15
                              Originally posted by RadioRoy View Post
                              That is interesting. What is the advantage of no timing advance mechanisms in the distributor? Do you have something somewhere else in the engine that will advance timing as needed?
                              Yes, as mentioned in my original post, MSD 8981 timing computer (I think I typo'd the model #). Regardless of what the timing computer is-or isn't-doing, the timing light doesn't lie. I have the tc set up to deliver 20 degrees of ramped advance and it is doing exactly as told. My concern is running a supercharged motor with apparently over 44 degrees of total advance to get it to perform right. I've run normally aspirated sb Chevys and Fords with that much and more, but a supercharger changes the whole game.

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