Possible fix for a noisy/rattling 355 exhaust valve | Page 2 | FerrariChat

Possible fix for a noisy/rattling 355 exhaust valve

Discussion in '348/355' started by f355spider, Dec 29, 2007.

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  1. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    Mine went back into place easily.

    Now that mine is back in place the rattle is significantly reduced, but still there, I might have turned the valve out one more time to tighten it up a bit more. Upon test drive the car does not seem to have the power at the top end, also the "scream like a banshee" is no longer there. I do not want to push the car for fear that the valve is not opening and I do not want to cause damage to the engine.

    Is it possible that the valve is not opening? How can I check for correct operation???
     
  2. Monteman

    Monteman Formula 3
    Rossa Subscribed

    Feb 9, 2006
    2,348
    Santa Barbara, CA
    Full Name:
    Monte
    To check the valve operation, just start the car (and let it warm up so you're not revving up a cold engine) and have someone stand behind the car with the rear hatch open and look down at the bypass vale from above. When it's revved up (4K RPM+) you should be able to see the valve open and close.
     
  3. cf355

    cf355 F1 Rookie

    Feb 28, 2005
    4,208
    Full Name:
    chris
    I did'nt know the valve would open while the car was rev'd while in neutral.
    I thought you had to have it in gear. ????? Has anyone tried this on a 1995 ?
     
  4. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,055
    USA
    Cary, you also need to confirm that there is not another source for the rattle. I had two others that had to be corrected. One was the heatsheilds on the Y diverter pipe to the exhaust valve. They are only crimped at the ends, and over time get loose and rattle around. I had mine tack welded at each end. Also the heat sheilds on the cats can also get loose and rattle. My left side cat sheild was loose and I also had it tack welded in place. So look around, grab and pull or try to slide these sheilds around and see if you get movement....if you do, then when under way they can rattle around pretty significantly.
     
  5. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,055
    USA
    Also, per the Work Shop Manual, the car needs to be fully warmed up before the exhaust valve will be allowed to open. So warm up thoroughly before testing.
     
  6. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    I will try testing tonight. I ALWAYS warm up the car before driving!!!
     
  7. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    I warmed up the car and had my wife take it to 6k, the valve does not move. The car also has a muffeled sound. When driving it has the same muffeled sound and the upper end power seems reduced, so I am sure it is not opening at speed either.

    Perhaps I need to take the assembly back apart and unload the spring a bit and live with the rattels.

    The valve is vaccuum driven, did I need to bleed anything???
    Any other suggestions???
     
  8. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
  9. yfc

    yfc Karting

    Dec 23, 2003
    212
    Geneva / Switzerland
    Full Name:
    Christophe
    I confirm that on my 97's 355, the by-pass valve open even in neutral. You need to rev a "bit" the engine ;-)
     
  10. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    I was up at 6,000, it was not moving and the engine was muted.
     
  11. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    Is it safe to remove the vaccuum hose while the car is running to see if there is any suction at 4-6k?
     
  12. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,055
    USA
    Strange, it almost sounds like there is a leak in your vacuum line. I guess you could adjust it back to it's previous position as a test.
     
  13. Testa

    Testa Karting

    Mar 28, 2004
    50
    You will have to check the valve during rev up (and you have to rev up quickly). If you keep the rpm at the same level or only rev up slowly the valve will close again. This is at least what my '95 model does.
    Driving with a always closed valve is not a good idea if you rev up hard >4000 rpm.
     
  14. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    I took off the airboxes and shiels again so I could see the valve clearly. With my wife revving the car quickly the valve does not move. I also checked the veccuum hose at the bypass and tightened it,still no movement. Playing with the valve I noticed that it would take quite a bit of pressure (a few more turns out) to stop the rattle. The amont of rattle is livible at this point, if the valve worked. I did manually open the valve, put my finger over the vaccuum port and the valve stayed open, so it is not a torn diaphram.

    I am going to get contact cleaner to clean the solinoid, and see if that helps. I could loosen the valve again to see if that fixes the issue, any other suggestions?
     
  15. cf355

    cf355 F1 Rookie

    Feb 28, 2005
    4,208
    Full Name:
    chris
    From what you describe , the first thing I would check is the vacuum.
    Goto to your local auto parts store and pick up a cheap vacuum gauge and see if there is vacuum on the line as you rev the motor (take it for a drive if possible..... and run it through the rpm ranges for this test and watch the gauge- but I would wire your bypass valve open for this test).....if no vacuum, then the problem is NOT your bypass valve but rather you need to check the vacuum lines and air canister(behind the right rear inner wheel well cover).
    You need to eliminate the basics before you proceed further.

    I just had a thought....before you do anything, why not adjust the bypass valve shaft tension to its original adjustment and see if it works as it did before......
     
  16. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    I am going to put it back to the original tension and try that, back to super rattle!
     
  17. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,055
    USA
    Or buy a new one from Daniel... ;) Or that new trick version from Capristo.
     
  18. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,055
    USA
    BTW, I have confirmed if the water temp isn't up to around 175 degrees f the solenoid will not activate the valve to open the vacuum line to the exhaust valve.
     
  19. Cinemagic

    Cinemagic Formula Junior

    Apr 28, 2007
    325
    Scottsdale, AZ
    Full Name:
    Cary Christie II
    For the short term I have it wired open...no time to play. During this summer, when I am redoing the interior, I will probably get the new capristo and take care of the engine as well..
     

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