White sparkplugs in front row, black in rear?? | FerrariChat
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White sparkplugs in front row, black in rear??

Discussion in '308/328' started by Gisle, May 20, 2013.

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  1. Gisle

    Gisle Rookie

    Jun 4, 2011
    30
    Norway
    Full Name:
    Gisle Platou
    #1 Gisle, May 20, 2013
    Hello i am the lucky owner of a carbed 77 GTB .
    When i had the annual change of sparkplugs, i noticed that the front row sparkplugs where almost white (to lean setting?), and the rear row black (to rich setting?). Is this; A carb issue? Ignition? One camshaft a notch wrong? - all of the above or maybe something else?
    The car seems to run ok but I am a little bit unsertain about the engine sound, i believe it is not as sweetsounding as it used to be.
    I have noticed a little sweat from the rear carbs.
    Last year i removed the restricting sound silencer in the filterbox inlet. No dramatic change of performance but it seemed moore eager / happier above 6500RPM. (Beautiful carb sound)

    Someone been there before? I would like suggestions where to start.

    Gisle
     
  2. Ferraripilot

    Ferraripilot F1 World Champ
    Owner Project Master

    May 10, 2006
    17,849
    Atlanta
    Full Name:
    John!
    #2 Ferraripilot, May 20, 2013
    Check the ignition on both banks first. Is this a US or Euro car?
     
  3. Gisle

    Gisle Rookie

    Jun 4, 2011
    30
    Norway
    Full Name:
    Gisle Platou
    #3 Gisle, May 20, 2013
    Hello, it is a US, twin distrubutor without airpumps or cats. The second pair of points is removed.
     
  4. hoverland

    hoverland Formula Junior

    Aug 14, 2010
    265
    Norway
    Full Name:
    Harald Ø
    #4 hoverland, May 20, 2013
    Checking and comparing dwellangle & dynamic ign. timing for forward/aft bank will give you good information with minimum effort.

    Harald
     
  5. don_xvi

    don_xvi F1 Rookie

    Nov 1, 2003
    2,934
    Outside Detroit
    Full Name:
    Don the 16th
    #5 don_xvi, May 20, 2013
    I'd say to look into the rods connecting the front carbs to the rear.
    Pick up a carb airflow meter if you don't already have one and do the carb sync process. It's spelled out rather minimally in the service books that you may have, or there's an adequate tutorial on Birdman's Ferrari site.
     
  6. Fairview

    Fairview Formula 3

    Mar 16, 2009
    1,109
    Waynesboro, Virginia
    Full Name:
    Jeff Ward
    #6 Fairview, May 20, 2013
    And if your choke control is still connected, make sure the choke lever arms on all the carbs are going back fully off. An out of adjustment choke control linkage could definitely make two carbs on a bank richer than the other two.
     
  7. Gisle

    Gisle Rookie

    Jun 4, 2011
    30
    Norway
    Full Name:
    Gisle Platou
    #7 Gisle, May 20, 2013
    Thanks to all of you.
    I will check out your suggestions next weekend.

    Gisle
     

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