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Idit piston rings

Discussion in '6.9L IH & 7.3L IDI Diesels' started by frankenwrench, Feb 13, 2020.

  1. frankenwrench

    frankenwrench overkill is under rated!

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    I read through a large amount of the tech article and found part numbers for the na rings but didn't find a part number for the std idit piston rings. Any clues?
     
  2. Philip1

    Philip1 Full Access Member

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    As far as I'm aware the piston rings are the same between the idi and idit. Someone with more knowledge than myself might correct me but I'm pretty sure only the wrist pin (and related parts) are different

    Sent from my SM-G975U using Tapatalk
     
  3. u2slow

    u2slow Plan B

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    The factory IDIT uses keystone shaped rings. They are self-cleaning, and seal better to deal with the higher cylinder pressures of turbocharging. You find this design in most industrial diesel engines.
     
  4. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    The 6.9 / 7.3 all use keystone rings as I recall.
     
  5. aggiediesel01

    aggiediesel01 Full Access Member

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    You may be correct and I don't know otherwise but the "coffee table book" for the IDIT touts the keystone rings for their qualities as noted above.

    image.png
     
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  6. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    The na IDI rings are not keystone like the idit rings, here’s some specs on the various IDI rings.
    IDIT rings top to bottom:
    1/8” 6* keystone
    5/64” 3* keystone
    9/64 oil control ring

    1994-1989 na 7.3:
    1/8” conventional
    5/64” conventional
    9/64” oil control

    The 88 7.3 is 5/64, 5/64, 9/64 and the 6.9 is even smaller at 5/64, 5/64 and 7/64.
     
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  7. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    Thanks for clearing that up Wes. I looked at some pistons this morning before I found your posts. I guess I’m just used to diesels having keystone rings. The first diesel I ever rebuilt, a Waukesha 190 DLC had them. But the 6.9 piston I have on my bench doesn’t. Guess I shouldn’t post from the campfire lol.
     
  8. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    Wasn’t my intention to “internet correct” anyone haha, just sharing what I’ve found. Really any diesel should have keystone rings, just another reason to build an idit over the older idis.
     
  9. aggiediesel01

    aggiediesel01 Full Access Member

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    Any idea why your measurements and the book are different? Early vs late, preproduction vs actual, typos from engineering?
     
  10. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

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    It’s possible that is the degree of the keystone in the ring land not the actual ring that they are referring
     
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  11. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

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    No need for you to apologize Wes, I was the the one talking without checking facts first. Glad you are here with fact checked info.
     

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