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12 valve with a terrible fluttering paper bag sound from exhaust. HELP!!!

12 Valve 2nd Gen Dodge Cummins 94-98 Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps

12 valve with a terrible fluttering paper bag sound from exhaust. HELP!!!

  #41  
Old 02-24-2019, 01:09 PM
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Itís a nick name I was givin back in my mini truckin days about 20 years ago. Fieval was the nick name and FON is short for Freaks of Nature, a car club I was in at the time. Been using it as a user name and such ever since.
 
  #42  
Old 03-11-2019, 12:34 AM
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Just a quick update for those who still follow this post. Installed a new adjustable over flow valve and just as I suspected there was no change. Iím not surprised but it was worth the $60 chance that it might have had something to do with it. Any new clues out there possibly?
 
  #43  
Old 03-11-2019, 05:12 PM
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No, but the adjustable valve is nice. They wear out, but when the adjustable one starts to get worn, you just tighten it up a little bit and pressure is GTG again. This is the strangest 12v thing I've ever heard of.
 
  #44  
Old 03-24-2019, 11:24 AM
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I too, would like to see the results of a compression test on all 6...you have not mentioned excessive blow-by and it appears that you may have addressed valve seating (with new head) and setting lash. Have you gone over the crankcase breather system to assure it's OK?
I was reviewing the suggestion made earlier to jam something in the compressor to take the turbine rotation out of the equation in the exhaust..while I admit at first glance it seems crazy and counter intuitive to do so, (we tend to protect that opening from foreign objects)...but I was wondering how much force is really on the turbine and if it could be held stationary without damage to the compressor wheel....???
Without hearing the sound, we are guessing, but I tend to lean toward a sound created by 1 or more, cylinder misbehaving through the exhaust valve...or a bad injector...but you replaced those...how about a weak exhaust spring? Did those get checked with the new head and I assume, new valves? Are the rockers the originals or after market? Pushrod lengths checked? Each rocker going through full valve open motion when barring over engine (cam lobes OK?)
 
  #45  
Old 03-26-2019, 02:30 PM
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Iím with you guys on doing a compression check. Iíve exhausted all efforts at this point besides a compression check which Iíve been hoping and praying all along is not the coperate. To answer your question Windage, yes all new 60# springs were installed (exhaust and intake). Push rods and rocker arms are stock just modified pedastools for the install of the head studs. I have no idea about the cam lobes, a lot of work to try and examine cam lobes so I havenít gone that far yet obviously. I do plan on try to stop the compressor wheel with a piece of wood at some point as im certain that will not damage anything but I have high doubts that is the issue any ways. Exhaust has made this noise with two different turbos including the factory HX and Iíve heard plenty of other trucks with factory HX turbos that do not make this particular sound. Anyways, as soon as I find a few things out I will let you all know. Thanks for the help to this point guys, just too bad I still havenít figured this thing out.
 
  #46  
Old 03-26-2019, 04:11 PM
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well...sounds like you eliminated weak spring. could you borrow a mag based dial micrometer and check the arc of rocker motion against each other? pain in the ***, I know...but you haven't eliminated a worn cam lobe just yet. My reasoning is; if one cylinder isn't performing like the others, it could add a wonky tone to the exhaust.. Have you run a temp gun on each exhaust outlet to compare temps?
 
  #47  
Old 03-27-2019, 12:42 AM
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To be honest windage, I wouldnít even know how to go about using a mag base micrometer to do that test even if I did know someone that had one. Lol. But yes I did do the temp gun test awhile back and from what I remember nothing seemed awry. Iíll do that test again though just to double check. At this point Iím definitely leaning towards the worst and having to assume bad rings and low compression at this point. Obviously I wonít begin a rebuild though with out first doing a compression check and confirming but gut says thatís going to be a disappointing test. The truck seems to have plenty of power and moves right along down the road but then again not quite as peppy as Iíd assume a 12 valve would be with all the upgrades Iíve done.
 
  #48  
Old 03-27-2019, 08:57 AM
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I follow several youtube channels with good guys that know their way around a 12 valve...DeBoss Garage and Power Driven Diesel are some of the best...imo here is a link to DeBoss;
plenty of others too. There are also several good 'leak down' test vids...good luck and keep us posted on test results..
 

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