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Too much advance?

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  • Engine: Too much advance?

    Since rebuilding my 60 Lark’s 259 (and adding Edelbrock 4bbl, aluminum radiator and refurbishing most everything else) I noticed the engine runs warmer at speed compared to say idling in traffic. The gauge reads at the top end of operating range on the highway and back down to the middle around town.
    I replaced the vacuum advance with a NAPA replacement (Delco window type distributor), I was wondering if it advances too much at speed causing heating? Timing is spot on and I’m using correct vacuum port.
    Not a huge deal as the car runs sweet and gets pretty good mileage, but inquiring minds need to know!

  • #2
    Have you tried hooking a MitiVac up to the vacuum advance and measuring the degrees of advance? Look in the Studebaker Shop Manual and that will give you the specs (advance at a certain vacuum)......pull a vacuum on the advance canister and see how much advance you have. You will need either a dial-back advance light or mark the vibration damper so you can determine how many degrees advance you get. Compare that to the Stude vacuum advance specs and you will know if you have more or less advance, and whether the advance comes in earlier or later.

    What do you have your initial timing set to? Have you measured your centrifugal advance to make sure it's working properly (you can plot the centrifugal advance degrees versus rpm and compare it to the Shop Manual specs)? Is you dwell set to specs?

    Timing too retarded could also cause overheating.

    EDIT: during all this work, did you have the cam out and/or timing gears off? If so, are you positive that the gears were reinstalled in the right position in relation to each other? You mentioned that you are using the correct vacuum port on the carb -- which one are you using? Have you tried swapping to the other port to see if it makes any difference?
    Last edited by r1lark; 08-17-2018, 08:50 PM.
    Paul
    Winston-Salem, NC
    Visit The Studebaker Skytop Registry website at: www.studebakerskytop.com

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    • #3
      Short answer - no. Retarded timing runs hot.

      Too much advance pings when hot.

      jack vines
      PackardV8

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      • #4
        If you replaced your vacuum advance with one you picked up at NAPA, you probably put one on for a Chevrolet, which is very wrong for a Studebaker. I would have to dig for the specs for each one, but I do have then. A Studebaker has a much lower vacuum signal at low speeds, thus the advance unit is matched to that. A Chevrolet has a strong vacuum at low speeds, and, the proper advance unit is tuned to that. So, your advance unit is probably not working much at all, since it would take much more vacuum to make it work.

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        • #5
          What Jack said is partially correct.

          1. Low ignition timing - Additional water temperature.
          2. Book ignition timing - Reasonable water temperature.
          3. Slightly higher than "book" timing - Lower water temperature.
          4. Too high timing, into detonation/pinging - also leads to higher water temperature.

          All four of those lines have caveats to them.
          1. Lower fuel mileage, lower performance.
          2. Again, the word...reasonable...
          3. Better fuel mileage, better performance (more fun..!).
          4. Lower fuel mileage, lower performance, high potential for part damage.

          Note that the addition of a new/working vacuum canister 's additional ignition timing, is limited by the designers. IF...the initial timing isn't over done, the addition of the vacuum induced timing shouldn't hurt anything. This also depends on whether you are using ported or unported vacuum.

          Mike

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          • #6
            Also confirm the springs in the centrifugal advance are not broken or weak. I had a broken spring in the mechanical advance once and had a severe over heating issue at speed, idle was ok. The springs have a design pull strength but you would have to look that up. Every body has their opinion as to the correct timing settings either at idle or static, anything from +4 to -4 or 0 degrees. The vacuum advance only works when there is sufficient vacuum otherwise the centrifugal advance does all the work most of the time. Early engines did not have the accessory vacuum advance and only relied on the mechanical advance, and earlier yet the advance was controlled by the driver.

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            • #7
              You can install an adjustable vacuum advance unit. There's a small screw inside the tube where the hose fits that lets you taylor it. It looks like this: Note hex below hose nipple.

              I don't run mine with ported vacuum, it's connected directly to the manifold. I set the timing at the IGN mark at 700rpm with vacuum advance disconnected. Connect the vacuum and advance goes up 3 degrees. By 1500rpm the mechanical advance is all in at 30 degrees. By 2500rpm the combined vacuum and mechanical advance brings total advance to 45 degrees. Runs like a scalded dog, no pinging or temp issues.
              sigpic

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              • #8
                Check out my post below for the right NAPA part numbers for the Stude Delco application. I’ve gotten the wrong part in the right box.

                https://studeblogger.blogspot.com/search?q=Distributing

                Clark in San Diego | '63 Standard (F2) "Barney" | http://studeblogger.blogspot.com

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                • #9
                  Thanks for all the advice and information gentlemen! I replaced advance springs (which were shot) and yes I believe the advance unit was a Chevy unit. I will investigate further and report back. I just finished a 300. plus mile trip this weekend and the Lark did great on the freeway!

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                  • #10
                    Update on this situation: I had the vacuum advance hooked up to the "timed vacuum" port on the Edelbrock instead of the "manifold vacuum" port. Instead of reading the directions I messed around with a timing light and removed/plugged the vacuum line and compared with the centrifugal advance only. THEN I read the manual which told me I had it hooked up wrong. After switching ports I then took the Lark out for a test run, and the power has improved plus the heat gauge needle backs off at hiway speeds with the increased air flow. Even tho the 259 ran great before at hiway speeds, it now has more acceleration power.

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                    • #11
                      Originally posted by BRUCESTUDE View Post
                      Update on this situation: I had the vacuum advance hooked up to the "timed vacuum" port on the Edelbrock instead of the "manifold vacuum" port. Instead of reading the directions I messed around with a timing light and removed/plugged the vacuum line and compared with the centrifugal advance only. THEN I read the manual which told me I had it hooked up wrong. After switching ports I then took the Lark out for a test run, and the power has improved plus the heat gauge needle backs off at hiway speeds with the increased air flow. Even tho the 259 ran great before at hiway speeds, it now has more acceleration power.
                      I'm more than likely running the same set up as you are on my 259. It certainly woke up my ole 62 Hawk. Now I just need a 6 speed in it. LOL
                      Jim Kaufman
                      Kearney NE

                      1952 2R10
                      1953 Champion (sold it and still kicking myself)
                      1962 GT Hawk
                      1963 R3984 Avanti R1

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                      • #12
                        Using the timed or manifold only affects the advance at idle. At cruise there is no difference as the timed port is fully uncovered.
                        78 Avanti RQB 2792
                        64 Avanti R1 R5408
                        63 Avanti R1 R4551
                        63 Avanti R1 R2281
                        62 GT Hawk V15949
                        56 GH 6032504
                        56 GH 6032588
                        55 Speedster 7160047
                        55 Speedster 7165279

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