Spark Pulg Problem Identified - Solution unclear | FerrariChat
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Spark Pulg Problem Identified - Solution unclear

Discussion in '308/328' started by lewis, Aug 20, 2010.

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  1. lewis

    lewis Karting
    Silver Subscribed

    Feb 11, 2004
    144
    South Florida
    #1 lewis, Aug 20, 2010
    Last edited by a moderator: Sep 7, 2017
    Ok - the detective work had paid off.

    Please recall I was having an issue. My 1988 328 GTS was running on only 7 cylinders. I located the problem which was the Plug on the HT Leads from the front #4 cylinder was popping off:

    http://ferrarichat.com/forum/showthread.php?t=292770

    I noticed that the "problem cylinder" - the one where the plug kept popping off - there was a lot more "grim" around the spark plug and the HT Leads compared to the other cylinders. I switched the HT leads and that did not solve the problem. I then got a bore scope and BINGO - I think I have identified the issue.

    If you look at the first two pics below of the "problem cylinder" you will see that there does not appear to be a complete seal around the spark plug. Compare this to the bottom two pics from of the "good cylinder". The good cylinder appears to have a seal around the entire plug.

    Is there a simple solution or is this a big issue. I searched this forum and my recently downloaded owner’s manual/workshop manual and I could not find this problem elsewhere.

    Sorry for the grainy photos - I was taking a pic of the screen on the bore scope.

    The first two photos are the "bad cylinder"
    The last two photos are the "good cylinder"

    Thanks for your help

    Lewis
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  2. flyngti

    flyngti Formula 3

    Jul 16, 2009
    1,256
    Snohomish, WA
    Full Name:
    Eric L
    #2 flyngti, Aug 21, 2010
    Have you pulled the offending plug? A spark plug has a captive crush ring which seals it when tightened. It's possible that you have a plug with a damaged or partially missing crush ring. I would carefully unscrew the plug maybe half way, then put the scope back in the plug well to see if the crush ring is intact or if it's broken. If it's broken and you have a piece of the ring floating around, fish it out with some stiff wire and then remove the plug.

    Boroscopes -- 1001 uses.
     
  3. thecarreaper

    thecarreaper F1 World Champ
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    Sep 30, 2003
    18,130
    Savannah
    #3 thecarreaper, Aug 21, 2010
    we use very nice borescopes at work on aircraft frequently. i really need to get one for my shop at home !
     

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