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Can a Lost Motion Assembly go bad?

Discussion in 'General Tech and Maintenance' started by D See 2, Apr 21, 2004.

  1. D See 2

    D See 2 Senior Member

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    just wondering because there has been an annoying rapping sound coming from my head. (1g b16a) i have titanium retainers and dual valve springs installed along with comp cams stage 2 camshafts. i've checked the valve lash several times and everything is within spec. so my question is... with the higher lift of these cams... could or can the LMA's go bad or become worn out?
     
  2. cws13

    cws13 Senior Member

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    I have never seen or heard of it. If you have a very agressive ramp on your cam profile you can chew up the whole valve assembly in time. Not really with those cams though.
     
  3. D See 2

    D See 2 Senior Member

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    valve assembly meaning rocker arms etc...
     
  4. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    Yes, LMAs can go bad. If you want to do a quick check, press down on the LMAs through your followers, and make sure that none of them are sticking. When you go with larger cams, you generally want to get ITR LMAs. They have a bit more clearance for larger lobes. With cams that are about ITR sized, you can use stock LMAs- for larger cams, it's safer to use new ITR LMAs. I had a funny noise in my B16's head, and it turned out to be sticking LMAs.

    If your LMAs are sticking and you don't want to spend cash buying new ones, you can try to refresh them by removing and soaking them in a tub of fresh engine oil overnight. Sometimes that helps them to loosen up.
     
  5. 97CTR

    97CTR Senior Member

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    What valve lash are you running?
     
  6. D See 2

    D See 2 Senior Member

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    int.: .006 in.
    exh.: .007 in.
    stock specs... i have a feeling the LMA's are bad.
    It sounds like the cam is "slapping" the rockers arms. I'll pull the valve cover off today and see what i can find out...
     
  7. xj0hnx

    xj0hnx I wanna be sedated VIP

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    Keep us posted, when I switched to CTR cams there was a lot more valve noise coming from the VC than before using stock B16A valve clearance specs, maybe it has something to do your issue.
     
  8. cws13

    cws13 Senior Member

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    Ditto, new one on me. I'd like to know what it turns out to be. Good luck. ;)
     
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