Valve Clearance Increase or decrease? | FerrariChat
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Valve Clearance Increase or decrease?

Discussion in 'Technical Q&A' started by gatsby, Jul 2, 2005.

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  1. gatsby

    gatsby Karting

    Apr 26, 2005
    206
    half moon bay, CA
    Full Name:
    jim
    #1 gatsby, Jul 2, 2005
    I was curious to hear from the techs out there if valve clearance should be expected to increase as the engine operates? I seem to have read somewhere that sometimes valve clearances will decrease over time as the engine gets used. Is this true? I never really paid too much attention when I adjust valves but I seem to recall that some clearances were "tighter", but most were a little loose.
     
  2. Lawrence Coppari

    Lawrence Coppari Formula 3

    Apr 29, 2002
    2,192
    Kingsport, TN
    Full Name:
    Lawrence A. Coppari
    #2 Lawrence Coppari, Jul 2, 2005
    I have to think the clearance lessens as they wear. The back side of the cam gets no wear and that is where you take the measurement. So what wears? The 'hockey puck' is hardened and remains flat. The valve continually beats on the cylinder head. Thus the valves gradually wear away the head where they seat. Or the valve where it seats can wear along with the head area. That would reduce clearance.
     
  3. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,367
    NY
    #3 Steve King, Jul 2, 2005
    Valves pound in the head so the clearance is less. This is normal wear. You will find that the exhaust valves "tighten" up faster then intake so pay attention to the exhaust. Did mine at 30k and found only 2 exhaust valves .001 tight. Simple job and used ferrari shims.
     

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