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Lost motion assembly

Discussion in 'Engine Building' started by CRXSIR1, Oct 29, 2003.

  1. CRXSIR1

    CRXSIR1 Junior Member

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    How do you determine if a lost motion assembly needs to be replaced?
     
  2. B16

    B16 Super Moderator VIP

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    press down on it and see if it sticks down
     
  3. CRXSIR1

    CRXSIR1 Junior Member

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    Can lost motion assemblies be repaired? My car has a clacking noise on start up, could this be caused by the lost motion assemblies? Clacking noise goes away after a minute or so.
     
  4. CRX_B16B

    CRX_B16B Senior Member

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    It depends how loud it is it could just be valve lash and when your engine heats up the parts expand and close the gap
     
  5. CRXSIR1

    CRXSIR1 Junior Member

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    It really isn't a clicking noise like valve lash, it is a loud CLACK,CLACK CLACK. If it were a push rod engine it would sound like a collapsed lifter.
     
  6. biglew

    biglew Junior Member

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    Has anyone changed out their LMAs here? How difficult was it. My engine is an H22A but I figure it's pretty similar in most Honda DOHC Vtec engines.
     
  7. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    I'm doing mine tomorrow... it's not that hard. Just get a service manual and go at it.
     
  8. biglew

    biglew Junior Member

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    So how did it go?
     
  9. Canuck 93 Civic Si

    Canuck 93 Civic Si Senior Member

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    Maybe you have a loose rod bearing like my car :eek:
     
  10. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Got them in, didn't help- Canuck- maybe you're right. We'll see.
     
  11. brettII

    brettII KMS-fab

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    this may seem dumb, but what is the LMA? sorry if that is a bonehead question but....thanks

    brett
     
  12. Paperchaser013

    Paperchaser013 Member

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    call me dumb, but was tha hell is that?
     
  13. Paperchaser013

    Paperchaser013 Member

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    yippe im not dumb any more!!!


    A lot of people don't know what these are/ what they do, so...

    Think of a lost motion assembly as a shock absorber for the mid- lobe rocker arms. They sit in the head under the mid rockers. What they do is that they give support to the mid rocker (aka the VTEC lobes) during non-vtec rpms. When vtec kicks in, the mid rockers are locked with the primary and secondary rockers, and what happens is that the big lobes (the middle) of the camshaft push the mid-rockers down, which in turn pushes the primary and secondary rocker arms down, which open the valves.

    Hopefully that makes more sense... and note, that this is for DOHC VTEC motors. SOHC VTEC motors operate slightly different, but have the same concept of offering support to the vtec rocker.
     
  14. B16

    B16 Super Moderator VIP

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  15. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    :werd:

    Good explanation. I'll post pics of the assembly tonight or tomorrow.
     
  16. CivicMasterEX

    CivicMasterEX New Member

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    ticking/tapping

    i have a 97 civic ex. D16Y8. it is tapping at idle. nothing bad, no power lost. and when driving i can hear a little pinging. but i was wondering what i could do to fix it. i have drove it for 3000 like this and not seem to get any worse. just annoying. someone please help. thank
     
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