Head Bolt Re-torque

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

  1. BMcF
    Joined: Mar 2007
    Posts: 1,173
    Likes: 182, Points: 63, Legacy Rep: 361
    Location: Maryland

    BMcF Senior Member

    100% correct.
     
  2. Moggy
    Joined: Feb 2011
    Posts: 181
    Likes: 8, Points: 0, Legacy Rep: 76
    Location: Somewhere else!

    Moggy Senior Member

    I must be VERY lucky.
     
  3. CDK
    Joined: Aug 2007
    Posts: 3,324
    Likes: 148, Points: 63, Legacy Rep: 1819
    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
    Posts: 2,944
    Likes: 67, Points: 48, Legacy Rep: 719
    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...
     
Loading...
Similar Threads
  1. Scotro95
    Replies:
    1
    Views:
    5,808
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.