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Loud valve tap

Discussion in 'Technical Q&A' started by smithbb, Oct 4, 2004.

  1. smithbb

    smithbb Karting

    Jan 27, 2003
    69
    Lancaster, PA
    Full Name:
    Brad Smith
    I'm running a TR and recently developed a very noticeable valve tap during warm up at one cylinder. Just started in past week. Not sure why and how harmful this condition is. Any input on cause, potential harm and diagnosis for repair?
     
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  3. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,086
    Austin TX
    Full Name:
    Brian Crall

    An exhaust leak from one cyl can easily be confused with a valve tap and often goes away when warm due to thermal expansion of the parts involved. TR's have solid lifters so there would be little change after warming up unlike a 355 which has hydraulics, unless of course something is sticking. In any event I would have it diagnosed ASAP. A stethescope should help narrow it down very quickly, as would looking under the car to see if any nuts are missing at the manifolds where they attach to the heads or looking for any obvious signs of leakage at that point.
     
  4. smithbb

    smithbb Karting

    Jan 27, 2003
    69
    Lancaster, PA
    Full Name:
    Brad Smith
    Brian, thanks for the advise. It just seemed really strange it happened so quickly so maybe it is a manifold issue. I hope you're right! It is definitely related to expansion. The sound is so much like a cam lobe slapping. I'll check and get back with the results.
     
  5. smithbb

    smithbb Karting

    Jan 27, 2003
    69
    Lancaster, PA
    Full Name:
    Brad Smith
    Brian, had a chance to get under the hood. Seems the issue is a bearing in the AC compressor. I pulled the belt, everything quiet. I've needed to get the AC worked on anyway so this is just one more item for the list. Thanks for the read on it.
     

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