360 - Cracked manifolds? | FerrariChat

360 Cracked manifolds?

Discussion in '360/430' started by rainyz, Mar 27, 2025.

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  1. rainyz

    rainyz Rookie

    Jul 23, 2024
    15
    SF Bay Area
    Full Name:
    Jess
    I started noticing a buzzing sound coming from the rear during cold starts. From the many threads in the forum, it could be cracks in the manifold. Have a listen and help me confirm:



    It starts to become a bit more pronounced at the 30 seconds mark, then cuts off abruptly after 1 minute of idle.
     
  2. bonehead

    bonehead Karting

    Apr 21, 2007
    192
    TX
    Full Name:
    Ed
    Precat failure?
     
  3. andrejwolk1975

    andrejwolk1975 Karting

    Feb 28, 2020
    116
    Italy
    Full Name:
    Andrea M
    Exhaust side for sure: Metal expands with heat and "seals" the fracture.
     
  4. aventari

    aventari Karting

    Dec 9, 2010
    157
    San Diego
    You gotta poke your head around in the engine bay and listen where it's coming from. My tubi exhaust was cracked (not leaking yet) and I just welded it up

    A stethoscope or a long screwdriver can help sometimes
     
  5. Mario Andretti

    Mario Andretti Formula 3
    Silver Subscribed

    Aug 9, 2020
    1,776
    Boston
    My exhaust valves are rattling at times when cold.... start her up and put your hand on the valves in the back before they get too hot.
     
  6. KC360 FL

    KC360 FL Formula 3

    Jun 20, 2017
    1,948
    Melbourne Florida
    Full Name:
    KGC
    Be sure to check the Secondary Air Injection pump. Mine rattles a bit upon start up ( I have 30K miles on my 360) but after a minute or so it cuts off (as it should) and then it's all Ferrari music from there on. It's an emissions thing that is only in play upon a cold start up. I don't give it a second thought. I suppose someday I will address it. We don't have vehicle inspections where I live but it's possible that could be an issue if you did. However I highly doubt it since you would be pulling into the inspection station with a fully "warmed up" engine.
     
  7. rainyz

    rainyz Rookie

    Jul 23, 2024
    15
    SF Bay Area
    Full Name:
    Jess
    I tried this today but was difficult to pinpoint with the engine roaring away. I understand the stethoscope but what's the purpose of the screwdriver?
     
  8. rainyz

    rainyz Rookie

    Jul 23, 2024
    15
    SF Bay Area
    Full Name:
    Jess
    I've got a tubi on mine so no valves at the moment. And from the interior, the sound seems to be coming from right behind the glass panel.
     
  9. rainyz

    rainyz Rookie

    Jul 23, 2024
    15
    SF Bay Area
    Full Name:
    Jess
    Nice, I'm also at 30k, I'll check it out once I find out the location of the secondary air injection pump.
     
  10. sammyf

    sammyf Formula Junior

    Aug 13, 2004
    263
    Northern California
  11. CANDREAM

    CANDREAM Canada

    Nov 13, 2009
    407
    Burlington, Ontario
    Full Name:
    Sadi
    Table all possibilities and start the troubleshooting by eliminating one at a time. The easier ones, with the engine on, when I hear the buzzing, put your hand under the intake plenums, it is known that the butterflies linkage rattles from underneath , u could touch it and see if any difference. Also, when headers fail, when u turn off the engine after being fully hot, u will hear metal cracking (louder than normal) also watch for a white like dust everywhere in the engine bay…this is the fiberglass based (or similar) heat insulation being blow out of the heat shields. Last resort, smoke test them to be sure.
     
  12. aventari

    aventari Karting

    Dec 9, 2010
    157
    San Diego
     

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