355 - Chatter after engine is warmed up... | FerrariChat

355 Chatter after engine is warmed up...

Discussion in '348/355' started by F1ScuderiaTifosi, May 11, 2020.

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  1. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    HI all,

    Before I randomly begin replacing parts I figure I'd better ask for some helpful guidance and useful input from my fellow F355 folks :D

    My '95 has a weird quirk. At least I think it does. After my engine warms up and is idling I hear light chatter towards the front of the engine near the firewall behind the passenger's seat. It's not old school diesel engine loud, just noticable chatter. This sound was present before I had my EOS so I figured it was normal due to wear and tear of gear tolerances, etc. But just to make sure... I thought I'd ask y'all.

    The chatter does not become louder as RPMs increase. I only hear it during idle. I can't hear it from within the cabin either.

    Any ideas what it may be, if anything? Thanks in advance for y'alls time and consideration.
     
  2. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    Eric
    The chatter does not get louder but it does get faster with rpm's?
     
  3. PaulK

    PaulK F1 Rookie
    Silver Subscribed

    Apr 24, 2004
    4,603
    Michigan
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    Chatter could be a few things... It could be the hydraulic tightener, those things chatter when they start to weaken and aren't giving full tension on the belts.

    Also chatter could be the headers. When the headers crack it sounds like lifter tick.
     
    F1ScuderiaTifosi likes this.
  4. Kokose7en

    Kokose7en Karting

    Dec 5, 2019
    207
    SF Bay Area
    Engine mount collapsed. Engine touching something that makes a chatter. Only thing that I could think of that makes a noise that is not related to engine RPM. Maybe clutch/flywheel because your idling and you’re in neutral. Try pressing the clutch to see if the noise disappears.
     
    F1ScuderiaTifosi likes this.
  5. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    Eric
    It does not get louder he says but did not clarify if it gets faster or not with rpm's? That's a key bit.
     
  6. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    No thankfully it doesn't.
     
  7. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    Do you mean the chain tensioner? If so, is that accessible without having to lower her engine out? I hope it's not the headers.
     
  8. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    No sir, it doesn't get louder or faster with RPMs.
     
  9. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    #9 F1ScuderiaTifosi, May 12, 2020
    Last edited: May 12, 2020
    And thank you all for trying to help me figure this out. I appreciate it a lot.
     
  10. PaulK

    PaulK F1 Rookie
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    Apr 24, 2004
    4,603
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    There is no chain tensioner, but for the belts. It is what keeps the pressure on the belt to keep it taught. Yep that would require an engine out.

    Image Unavailable, Please Login

    https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/355-group/f355-m2-7-1995/timing-controls.html

    It has not happened to me but I remember people saying that when they start to go bad they rattle due to lack of proper tension.


    I suppose it could be a lot of things. How about a video? Can you post a video with good audio of what you are hearing?
     
    Michael Burgoyne likes this.
  11. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    I'll look to see if depressing the clutch quiets it down.
     
  12. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    #12 F1ScuderiaTifosi, May 12, 2020
    Last edited: May 12, 2020
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    I'll see about recording a video.

    What about the chain tensioner for the oil pump? Could that be a possibility?

    I found these photos on FLife (David@FluentInFerrari).
     
  13. Ferrarium

    Ferrarium F1 Veteran
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    Jul 28, 2018
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    Not saying it is the issue but the oil pump tensioner did rattle it was reported, as a result it was updated with the 360 which was then an update for the earlier cars.
    I read previously that these are candidates, not saying it is and of these just a list of some possible options:
    1. Exhaust bypass valve
    2. Broken isolator bush in rear silencer mounting
    3. Oil pump chain tensioner
    4. Piston slap
    5. Engine mount
    6. Header crack
    7. Heat shields
    8. Engine mounts
     
  14. PaulK

    PaulK F1 Rookie
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    Apr 24, 2004
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    I am sorry I misunderstood you. I didn't think about the chain that drives the oil pump.

    I'd also consider getting a mechanics stethoscope with a probe (I use this one, but I did polish the tip of the probe just to take the edge off https://www.amazon.com/gp/product/B0015DLMOO/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1) that way you can have yourself a listen around the engine.
     
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  15. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    The chatter is emanating from the front of the engine (firewall area) on the passenger side so I think #3, (I pray it isn't) #4 or #6 will be the first things I'll be looking at. Could even be an exhaust-gasket leak, correct?

    And like I mentioned, it only sounds off once the engine is close to reaching normal operating temperature so I'm thinking something (valve, etc.) opens/closes once the temperature is achieved then the chatter begins. 90% of the time I hear the chatter. Sometimes it's just that beautiful F355 exhaust symphony. *sigh*

    Does anyone know the operational sequence of the oil thermostat valve (#18)? Does it close or open at the precribed temperature? Could it be the valve is not opening/closing fully and in turn starving my oil pump? Just trying to think out of the box...
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  16. F1ScuderiaTifosi

    Mar 16, 2015
    131
    Hill Country TEXAS
    Full Name:
    JB
    PaulK likes this.

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