Head Bolt Re-torque

Discussion in 'Inboards' started by mikealston2428, Dec 29, 2014.

  1. BMcF
    Joined: Mar 2007
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    BMcF Senior Member

    100% correct.
     
  2. Moggy
    Joined: Feb 2011
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    Moggy Senior Member

    I must be VERY lucky.
     
  3. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Modern engine designs have camshafts mounted above the head bolts, so re-torquing after a few engine hours - like in the old days - is not an option anymore and a new kind of fasteners was developed.
    After obtaining the specified torque in 3 or sometimes 4 steps the bolts must be turned another half or 3/4 turn. You can feel and and see on the tool's scale you have entered a range where the material is subjected to forces it cannot recover from, just like in a hydraulic test bench that determines tensile strength.

    Because these fasteners are mass produced, they are cheap. If would be plain stupid to use them again in critical applications.
     

  4. powerabout
    Joined: Nov 2007
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    Location: Melbourne/Singapore/Italy

    powerabout Senior Member

    Did anyone mention what sealant was used on the chev head bolts as they go into the water so if it goes off you might create a leak re torqueing.
    I guess 30 million or so small blocks went out from the general without ever needing a re torque...
     
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