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OK - what is this noise???

Discussion in 'Technical Q&A' started by Crawford, Jan 2, 2004.

  1. Crawford

    Crawford Formula 3

    Mar 5, 2003
    1,294
    Nashville, TN
    Full Name:
    Crawford White
    Took the 328 out the other day. Warmed it up well and did some high rev shifting over the course of about a 30 minute drive.

    I was just about to go back to the house and gave it one more (fairly) high rev shift into second and I hear a whistling/whining sound as I goosed the engine up to about 6500 rpm. The sound went up and down in pitch along with the engine revs.

    Noise went away as I gingerly drove back to the house. Car runs fine and I didn't try to push it again but... what the hell was that!!
     
  2. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    16,558
    USA
    Full Name:
    Hugh G. Rection
    I had this happen with my 308! Stock exhaust, yes? What happens is the air flowing over the perforated metal in the exhaust tips causes the whistle. You can fix it by fabricating some little inserts from a piece of scrap stainless steel sheet metal. I tried aluminum and galvinized steel and the heat caused them to curl up tighter and blow out. Stainless works great. I local sheet metal fabricator gave me the scraps for free(actually I went back with two dozen donuts and made friends for life), and I cut them out with tin snips and slip them in. They only have to be about 3" x 5", roll it around a broom handle then carefully insert it in the exhaust tip. If you move it from tip to tip, you can fix just the offending one, or do all four.

    I have seen and heard other 308's do this, but not a 328, but they all share a similar exhaust.

    Here is a service tip on it I found later:
    http://www.modena-motors.com/308whistle.htm

    Tony suggests welding the inserts in place. I found the ss sheet metal to be "springy" enough to stay in place by it's own tension.
     
  3. Crawford

    Crawford Formula 3

    Mar 5, 2003
    1,294
    Nashville, TN
    Full Name:
    Crawford White
    Hi Dave-

    I've actually got a Tubi on the car, so I don't know if it's what you're suspecting...
     
  4. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    16,558
    USA
    Full Name:
    Hugh G. Rection
    Crawford, I am fully prepared to retract everything I say and deny that I every said it... :)

    Sounds like a belt or bearing noise of some sort then.
     
  5. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    15,222
    Savannah
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    name
    just a guess..... vaccume leak, alternator bearings, a/c clutch bearings. happy new year CRAWFORD! by the way , did the car have a Tubi on it when i got those ( great ! ) rides here at Roebling , or have you added that since? best of luck whatever it is. michael
     
  6. Crawford

    Crawford Formula 3

    Mar 5, 2003
    1,294
    Nashville, TN
    Full Name:
    Crawford White
    Yes, the car was tubified, Michael. And Happy New Year to you! Maybe 2004 is the year for your Ferrari????
     
  7. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    15,222
    Savannah
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    I sure hope so, ive sold off most of the " lesser" cars to make room for a fcar. we will see! please say hello to your wife for me, it was so nice meeting the two of you. please keep us posted on the mystery noise. michael
     

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