Oil pumps: Compare

Discussion in 'Modifications And Maintenance' started by Snowbum, May 10, 2009.

  1. Snowbum
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    Snowbum Well-Known Member

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    I have a WRX and EJ22t oil pump sitting in my garage. So, I did alittle research and measuring to figure out which should be used in the new engine.

    All "case" dimensions are within .001in of eachother, and the gear width (measured .393in/9.9822mm)/profile are the same.

    I've always been under the impression that the 22t pumped a larger volume. Although, after comparing both, I can only conclude that they are the same pump.


    [​IMG]
    Ej22t pump on left, WRX on right.

    [​IMG]
    Ej22t gears on left, WRX on right.

    Am I missing anything here?....:eek3:

    Feel free to post up any other findings, I am particularly interested in comparing these 10mm pumps to the 12mm.
     
  2. Nuke
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    Nuke Well-Known Member

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    the 22t's pump is shimmed.
     
  3. piddster
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    piddster Lone Wolf

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    What is the thinkness of the rotors?
     
  4. Snowbum
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    Snowbum Well-Known Member

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    They are both 10mm and I see no shims in the 22t.
     
  5. readymix
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    readymix ...Lest ye be trod upon... Staff Member

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    There are shims, otherwise you didn't disassemble it all the way. Or it wasn't an EJ22T oil pump.
     
  6. piddster
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    piddster Lone Wolf

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    I see the "10" on the 22T pump. I'm just surprised at the 10mm rotor of the WRX pump. The casting of hte WRX pump does not have the typical size designation on the inside, which is visible on the 22T pump.

    I want to see the bypass valve apart on both.
     
  7. Shibbs
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    Shibbs The Daywalker

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    The one on the right is the WRX pump with the 10 on it. I don't see any markings on the 22t pump tho.
     
  8. Snowbum
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    Snowbum Well-Known Member

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    [​IMG]

    Thats a shot of the inside, underneath the rotating gears of the pump. ej22t on left, wrx on right. Can it be taken apart any further?
     
  9. Threshld1
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    Threshld1 Well-Known Member

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  10. Snowbum
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    Snowbum Well-Known Member

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    Now this is very interesting:
    I removed the bypass valve on both pumps, the 22t pump had 1 shim and the wrx pump had 2.

    Is it safe to run 3 shims?
     
  11. Snowbum
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    Snowbum Well-Known Member

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    22t left, wrx right
    [​IMG]

    I was not expecting to see the shims in the wrx pump, was it manufactured shimmed/nonshimmed in different years?

    From what I have read, the spring rates are the same between the two pumps, is this true?
     
  12. subytek
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    subytek Well-Known Member

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    If I remember right, Jason is running 3 in his car.
     
  13. AWDimprezaL
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    AWDimprezaL has more posts than you

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    Dust thou haveth the best sounding stove pipes?
     
  14. FuJi K
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    FuJi K Well-Known Member

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    orly.... WRX has 2 shims.... must be the same for JDM. Meaning that would be for factory 8000rpm like JDM.