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54 running problems

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  • Don H.
    Infrequent User
    • November 3, 2009
    • 6

    54 running problems

    Hi Members,

    I require help with regards to my 54 Vette - i have had the engine rebuilt but have heaps of trouble to keep the car running right. The mechanic i am using is extremely reputable and specialises in Corvettes, but even by his own admission, is not fluent in these early models, and being in Australia - there is no-one i can find who is!! David (my mechanic) has listed below everything he has done. Does anyone out there have an idea on what we may be missing? Any help would be greatly appreciated.

    Many thanks

    Don Hailes

    Work that has been done
    fully rebuilt engine,
    rebuilt carburettors, correctly set float levels, carbs set up with reference to carter and chevrolet service instructions
    std jets and needles (I think) ?
    carburettors set up and balanced
    fuel pressure regulator fitted to drop fuel pressure from approx. 8.5 psi down to 2.5 to 3.0 psi to stop excess fuel passing needle and seat and running out of carb.
    ignition system -distributor fully rebuilt with new shaft etc and re-curved to suit, points gap set, timing set approx 30deg advance at 3000 revs, very good spark especially for 6volt system, etc
    Run on dyno
    fitted new spark plugs gapped 35thou
    engine ran very lean right through the rev range under load, however not running short of fuel : ie we had enough fuel volume.
    After driving vehicle back to workshop ( a 15minute drive) partly along freeway I pulled the plugs out to find them black as if running rich.
    Do these carbs flood during cornering or other driving conditions as I found this to be a little confusing?
    Attached Files
  • Roy B.
    Expired
    • February 1, 1975
    • 7044

    #2
    Re: 54 running problems

    A summing the engine was rebuild correctly !=( cam marks)
    1 Setting the valves cold then rechecking them when HOT to Corvette specks .
    2 Set the timing at zero for start up then when the engine is hot by hand advance Dist till the engine snap up at high RPM with out studdering then lock down.
    3 Set dwell at 30 degrees
    4 Set Carb floats lower then what the book says.(this is important )
    5 Recheck needle adjustment again and again
    6 Check that the Carb choke (IS) open when engine is hot
    7 re balance the Carb air-intake
    This is what I've done for many years and works for me.
    Then check back and let use know the results . Good luck

    Comment

    • Jack H.
      Extremely Frequent Poster
      • April 1, 1990
      • 9906

      #3
      Re: 54 running problems

      and being in Australia - there is no-one i can find who is!!

      Hum, I guess I beg to differ on this comment! Being a US native who's a founding member of the NCRS Australia Chapter, I KNOW there are Oz resident natives who ARE familiar with these cars. In fact, another founding member of the NCRS chapter there actually HAS a nice running '54...

      Comment

      • Chuck W.
        Very Frequent User
        • May 31, 2002
        • 257

        #4
        Re: 54 running problems

        What heat range plugs are you running?

        Comment

        • Jim L.
          Extremely Frequent Poster
          • September 30, 1979
          • 1808

          #5
          Re: 54 running problems

          Originally posted by Don Hailes (51008)
          After driving vehicle back to workshop ( a 15minute drive) partly along freeway I pulled the plugs out to find them black as if running rich.
          Do these carbs flood during cornering or other driving conditions as I found this to be a little confusing?
          I can't speak to the lean condition you noted, but rich conditions can be caused by a design problem with the YH carburetors. This thread, beginning with posting #19, describes it:

          https://www.forums.ncrs.org/showthre...62637&uid=6676

          Jim

          Comment

          • Don H.
            Infrequent User
            • November 3, 2009
            • 6

            #6
            Re: 54 running problems

            Thanks for the help guys - keep the advice coming!! i'm passing everything on to my mechanic.

            Comment

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