Does this sound like an exhaust manifold issue? (355) | FerrariChat

Does this sound like an exhaust manifold issue? (355)

Discussion in 'Technical Q&A' started by ian_uk1975, May 18, 2007.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. ian_uk1975

    ian_uk1975 Rookie

    Feb 19, 2007
    25
    Northampton, UK
    I have a 96 355B and I've suspected for a few weeks that I might have the beginnings of manifold issues on the right bank. At idle, the exhaust does seem quite noisy (stock system). However, having never head another 355 with a stock exhaust, I have nothing to compare it to. But, it does sound like the exhaust is blowing slightly. Also, and more tellingly, every now and again, I can hear what sounds like a 'spit' from the manifold area on the right bank. This is with the engine cover open and the car idling. Happens infrequently, but I have heard this very distinct sound on a couple of occasions. I suspect that I may have a slight crack in the manifold, but of course, I can't be sure. Also, when the car is started from cold and I gingerly press the accelerator (when inching out of the garage), the engine 'stumbles' a little (almost as if there's a inlet manifold vacuum leak). It's fine when the engine has warmed-up a little.

    I did take the car to a local specialist last weekend and he had a listen to it. He was of the opinion that nothing was wrong, but I'm still not sure! He was listening to the car with the engine hot, so it is feasible that a hairline crack in the manifold would close-up due to heat expansion with the engine hot.

    Is there any way to 'test' for a leaky manifold without dropping the rear subframe to visually inspect? I'm thinking in terms of EGT or temps around the manifold? Would it throw the lambda off on the affected bank? This is bugging me now and it's niggling at the back of my mind. I want to determine, conclusively, if I have a problem or not. If have looked for signs of insulating material blowing-out, but it all looks fine.

    Thanks,
    Ian.
     
  2. ian_uk1975

    ian_uk1975 Rookie

    Feb 19, 2007
    25
    Northampton, UK
  3. turbo993

    turbo993 Rookie

    Dec 6, 2005
    1
    I had a 96 f355 with the same problem like yours.It got worse and worse.It was the manifold,they melt and you cant weld them.Bought a pair of tubi manifold.little more money than the factory but made a big difference in power
     
  4. f355spider

    f355spider F1 World Champ
    Owner Rossa Subscribed

    May 29, 2001
    18,044
    USA
    One visual clue is to look all around the heat shields of the exhaust manifolds. Check for bits of insulating material being forced out. Pay particular attention at each end; the collector and at the mounting flange.

    If there is a decent sized crack, the pressure will start to force the material out. BTW, if it has gone this far, immediately quit driving it.
     
  5. ian_uk1975

    ian_uk1975 Rookie

    Feb 19, 2007
    25
    Northampton, UK
    Found the cause of my noisy exhaust today... sheared clamps around the junction between the cats (both sides) and the exhaust box. Will order new billet clamps and, hopefully, the car will sound a lot better for it :)

    Thanks for the advice guys.

    Cheers,
    Ian.
     
  6. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    Since you're in the UK already, support your very own Hill Engineering and get the VASTLY superior EC-355 clamps. They make the Ferrari ones look like complete junk.

    -d
     

Share This Page