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What's that round thing connected to exhaust manifold?

Discussion in 'The Garage' started by MilpitasK5, Dec 19, 2002.

  1. MilpitasK5

    MilpitasK5 1/2 ton status

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    What\'s that round thing connected to exhaust manifold?

    I didn't see exactly how it was connected but it looks like some kind of pump or something. It's on the passenger side. It's round and thick. Probably about 2" in diameter.
    The reason why I ask is b/c it looks like there should be a hose connected to it but it's free. Anyone know what the heck I'm talking about?
    /forums/images/graemlins/ears.gif
    Thanks
     
  2. Swanson52

    Swanson52 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    Exhaust heat riser valve? It generally has a chunk of flexible aluminized tubing running from it to the air cleaner.
     
  3. HarryH3

    HarryH3 1 ton status Author

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    Re: What\'s that round thing connected to exhaust manifold?

    Does it go to a set of small pipes that feed into each exhaust port? If so, then it's part of the AIR system that is supposed to feed fresh air into the exhaust stream. Fresh air comes from the AIR pump, then into the ports to burn any leftover fuel that couldn't burn due to a lack of oxygen. It reduces emissions and keeps the catalytic converter hot enough to do its job. /forums/images/graemlins/cool.gif
     
  4. Shaggy

    Shaggy 3/4 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    <font color="green"> It's the heat riser. From Thorley Headers -

    </font><blockquote><font class="small">In reply to:</font><hr />
    The heat riser is a valve that closes off the exhaust on one bank of a V-8's cylinders when it's cold. The heat riser routes the hot exhaust gases from the closed off bank, through the exhaust crossover at the center of the manifold, and out through the exhaust manifold on the open side. Heat risers are also known as early fuel evaporation systems (commonly referred to as "E.F.E. valves") There are two types of heat risers: mechanical and vacuum. The mechanical heat riser uses a bi-metallic strip that acts as a heat sensitive spring to open the valve. The vacuum heat riser (shown above) uses a vacuum canister to open and close the valve.

    [/ QUOTE ]
    <font color="green"> </font color>
    [​IMG] </font color>
     
  5. HarryH3

    HarryH3 1 ton status Author

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    Re: What\'s that round thing connected to exhaust manifold?

    Cool pic! I've never seen one of the vacuum operated heat risers! /forums/images/graemlins/shocked.gif I guess I've only seen the mechanical ones that are operated by a thermostatic spring.
     
  6. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    Okay Evan, I'm done thanking you b/c it's getting old /forums/images/graemlins/thumb.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif.
    Does this need a hose from somewhere to be connected to it? Where do I get it or where should it be from? /forums/images/graemlins/ears.gif

    Thanks guys! /forums/images/graemlins/thumb.gif
     
  7. Shaggy

    Shaggy 3/4 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    <font color="green"> I'm pretty sure it gets manifold vacuum. I'll look it up in my service manual if you want. </font color>
     
  8. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    That'd be great! /forums/images/graemlins/thumb.gif
    Of course, when you get the chance. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  9. Re: What\'s that round thing connected to exhaust manifold?

    I think you're ALL wrong! That's the muffler bearing. /forums/images/graemlins/rolleyes.gif
     
  10. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    Really? That pic that Shaggy attached is what I was asking about. What are you referring to? /forums/images/graemlins/ears.gif
     
  11. zakk

    zakk 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    this coming from a guy that can't figure out how to fill out a profile?? /forums/images/graemlins/rolleyes.gif /forums/images/graemlins/ignore.gif
     
  12. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    Awwww how cute!! /forums/images/graemlins/eek.gif /forums/images/graemlins/eek.gif Jokes on the guy that doesn't know crap about engines that and tryin' to learn...
    Thanks for your input too, buddy. Any help is always appreciated! /forums/images/graemlins/rotfl.gif
     
  13. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Re: What\'s that round thing connected to exhaust manifold?

    The vacuum heat risers are connected to a thermo control valve on the intake or the thermostat housing. If you hook it to straight vacuum it will be closed all the time and cause vapor lock as it boils the gas in the carb.
     
  14. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    </font><blockquote><font class="small">In reply to:</font><hr />
    The vacuum heat risers are connected to a thermo control valve on the intake or the thermostat housing. If you hook it to straight vacuum it will be closed all the time and cause vapor lock as it boils the gas in the carb.


    [/ QUOTE ]
    So that sounded like there should be something hooked up to it but not a vacuum line? /forums/images/graemlins/ears.gif
    So is there a hose or something from </font><blockquote><font class="small">In reply to:</font><hr />
    a thermo control valve on the intake or the thermostat housing.

    [/ QUOTE ]
    Thanks /forums/images/graemlins/thumb.gif
     
  15. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    Re: What\'s that round thing connected to exhaust manifold?

    Can you still get those?
    I tried NAPA, but they looked at me like I had 3 heads.
    I have yet to try the dealer.
    Any part numbers?

    Thanks. /forums/images/graemlins/thumb.gif
     
  16. Shaggy

    Shaggy 3/4 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    <font color="green"> Ahhh yes, that is correct, sir. Now I remember that from when I had to figure out what that funny lookin thing on my intake manifold is. /forums/images/graemlins/thumb.gif Thanks, Grim. </font color>
     
  17. HarryH3

    HarryH3 1 ton status Author

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    Re: What\'s that round thing connected to exhaust manifold?

    Sounds to me like there is supposed to be a vaccum line that goes to a thermostatic vacuum switch on the intake manifold. Another vacuum line goes from there to the heat riser. When the engine warms up, the heat riser opens and lets the exhaust flow freely. /forums/images/graemlins/cool.gif
     
  18. MilpitasK5

    MilpitasK5 1/2 ton status

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    Re: What\'s that round thing connected to exhaust manifold?

    Could that be part of the reason that I get some back-fire/gurgle when cold?
    So does anyone have pics of how that should look connected with the hose/vacuum?

    Sorry if I'm not picturing this right away. Still kinda cloudy /forums/images/graemlins/smirk.gif.
     

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