355 Muffler springs/bypass pipe adjustment | FerrariChat

355 Muffler springs/bypass pipe adjustment

Discussion in '348/355' started by Carmellini, Feb 8, 2021.

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  1. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    What is the function of the 2 springs that are located at the left and right of the muffler?

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    Are they simply for damping, or are they used for any adjustment purpose?

    Also, what is the purpose of clamp #9 at the forward flange for the secondary CAT?

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    I thought I read a post about these used for adjusting the angle of the bypass valve connection to the bypass port on the muffler?
     
  2. fboutlaw

    fboutlaw Karting

    Dec 3, 2014
    237
    Woodside, CA
    Springs are for both:
    1. NVH isolation
    2. Allows tolerance in design for metal expansion with heat.

    I'm no expert on part #9 as I have a '95, but it appears to be a clamp for part 7.
     
  3. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,212
    Los Angeles
    Curious as well about the hanger springs. I'm reassembling my exhaust after cat/muffler swap and have everything finger-tight so that cats/muffler/y-pipe/etc all fit snugly without leaks or undue stress on the components. Anyone know if there's factory guidance on this?
     
  4. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    I recently has some leaks and found that it was imperative to tighten both flanges at the header, first because the header is a fixed entity; unless items #6 provide for adjustment of the secondary cat? Does anyone know about that?

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    If you start from the rear, you will never get the donuts to seat properly. Once I secured the donuts, at the header, I then attached the connections at the muffler. I needed to push up a little bit on the muffler, in order to properly engage the fittings at the CATs. I am concerned that this might be pulling down the fittings at the header, or cause a crack?

    That is why I am interested in the adjusting points.

    There is zero information in the WSM about the exhaust fitment; Targatime, I highly recommend that after you finish, you smoke test to be certain the system is leak free.
     
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  5. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,212
    Los Angeles
    Thanks -- couldn't find any either. Definitely going to smoke test. I'm going to snug everything up iteratively, each component a little at a time, although probably will do a little more with the header/cat junctions first for the reason you mentioned. I'm probably overthinking it, but I also don't want to spend weeks chasing down OBD codes and air leaks.
     
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  6. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    ^^^^there must be a "formula" to follow for install? I understand its not rocket science, but it would be a lot easier to comprehend if we could understand the physics of the muffler spring points, and the slip collar at header to secondary CAT joint. Surely someone knows....??? Bueller.....Bueller
     
  7. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,628
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    Full Name:
    John Kreskovsky
    #7 johnk..., Feb 9, 2021
    Last edited: Feb 9, 2021
    Yes, not rocket science. Use a little common sense. Examine the system closely. The springs are not intended for adjustment. Look at part 41. There are vertical slots in it where bolt 45 goes through it to allow height adjustment. As for the slip collar, parts 8 and 9 slide over the collar, 7, then 7 slides over the header tube. The collar slides back and fourth to adjust to the proper length to meet the cat bypass tube. The clamp, 9, is then tightened using bolt 10 and nut 11 to prevent it from sliding once correctly positioned. Like any exhaust system all parts should be loosely fit and aligned before tightening anything. Start with the muffler height adjustment bolts, 45, so as to remove downward pressure on the headers. Frankly, if you need help to figure this out you shouldn't be working on cars, let alone a Ferrari. :(

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  8. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    Not productive, unnecessary, and inappropriate, not even if intended to be funny.
     
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  9. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    10,628
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    John Kreskovsky
    Did I answer your questions accurately and concisely? Yes.

    With 240+ views, did anyone else? No.

    Wonder why?

    The rest you'll have to deal with.
     
  10. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    Yes, you did. I appreciate the explanation and I hope it benefits Targatime and others, as well. Thank you.

    However, there was no benefit in your closing statement. We are all here to learn and I am very grateful to everyone with greater experience than myself.
     
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  11. Targatime

    Targatime Formula 3

    Feb 22, 2014
    1,212
    Los Angeles
    Thank you for your comments @johnk... and @Carmellini I wouldn't get bent out of shape, John's grumpiness is part of his charm. I get grumpy sometimes when noobs ask dumb questions about air-cooled 911's but buying a 355 has reminded me that a lot of what goes into "expertise" isn't pure mechanical aptitude or IQ but simply experience with a particular mechanical system and its quirks. I have a great deal of mechanical aptitude (built a few track engines, among other things) but very little 355 experience, and yes, the exhaust system is pretty different than other cars, which means there are things you wouldn't know or understand just eyeballing it. So I'm eager to hear tips and insights from people who may be less skilled with a toolbox than me but who have more experience working on 355's.
     
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  12. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    11,484
    Sydney
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    Ian Riddell
    I wonder how many people on the Ferrari/Boeing/Apple assembly lines understand how their products work? They just follow a set of instructions. Should they not have jobs?
     
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  13. emac

    emac Formula Junior
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    Sep 14, 2014
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    ernest
    Recently purchased a Stinger Brand smoke tester. Reasonably priced and very pleased with the quality. I have only tested the unit and haven't actually used it on a car, but it makes good smoke. Hopefully get around to smoke testing the 355 vacuum lines/intake and exhaust one of these days. The units get very good reviews. HTH
     
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  14. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    John Kreskovsky
    Here is my point. The exhaust system assembly is pretty straight forward. With minimal mechanical aptitude and skills a person should be able to figure it out. If a person need assistance doing so it raises the question, in my mind, as to the level of competence in working on mechanical things in general and perhaps should consider if they are really qualified to work on their Ferrari without messing something serious up.

    You have no idea how many people I know who work on their cars and, for example, will replace brake pads w/o replacing or resurfacing the rotors. Then they wonder why the pads wear out in 10k miles.
     
  15. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    Frankly, if you need help to figure this out you shouldn't be working on cars, let alone a Ferrari.
    Still a little harsh John.
    Everyone asks questions mate relevant or not. Some people including myself probably don't right the question appropriately. Lots of guys and gals do there own work and rely on the forum to enforce what there doing is correct.
    Anyways I like that your candid lol
     
  16. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    Is this for real? Seriously? You really want to continue criticizing another forum members "competence?" LOL

    I got your point the first time, loud and clear: you don't think I should own or work on any car. I fail to understand why you want to defend your overt condescension? Again, to MY point, what is the benefit and productiveness of this continued behavior.

    I believe I know what you are trying to say, however, here is an anecdote: "Joey's is a good boy; he only robs banks on Weds." It is amazing what it tolerated today. Unfortunately, I have been forced to expect bad behavior from our new generation that worships Cardi B "WAP," and the Kardashians; but on a Ferrari forum I expect a more mature member and attitude. The bar is not that high.
     
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  17. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    Criticizing, and diminishing someone's abilities is not candor. It's rude and needs to be called out and not tolerated.
     
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  18. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    Moving on: My right side exhaust tips extend a bit more than my left side. I noticed that flange #7 extends more on the right side:

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    Since this connects to the secondary CAT, I don't see how it might affect the tips? But perhaps it does?
     
  19. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    John Kreskovsky
    Without comment, I refer back to my post 7. Align thing properly and then tighten all clamps, etc.

    You don't have cats but the test pipes serve the same function. Part 28 is also a sliding piece. You need to adjust the position of 28 (forward or back) on each side so that the muffler pipes protrude from the bumper the same on both sides. So let's count them you have 4 sliding flanges that must be adjusted, 2x #28, and 2 x #7. You have two flares on the front of the test pipes and the test pipes must be rotated/positioned so that the flares mate properly with the donuts on the headers, otherwise they may leak. You have the muffler height adjustment. You also have an adjustment that allows slight left right movement of the muffler (see post 7, part 48). This and the muffler height may have to be adjusted to align the flanges between the muffler and the secondary cat exit.

    You said it yourself, it's not rocket science.


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  20. Carmellini

    Carmellini Formula Junior

    Jul 16, 2019
    814
    ^^^^ thank you.
     
  21. emac

    emac Formula Junior
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    Sep 14, 2014
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    ernest

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