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head bolts

Discussion in 'The Hokey Ass Message Board' started by rodzz2010, Jan 26, 2012.

  1. rodzz2010
    Joined: Feb 8, 2010
    Posts: 54

    rodzz2010
    Member
    1. A-D Truckers

    Is it adviseable to use grade 8 bolts for my 49 flathead stock heads? I just cant see paying alot of $$$$ for them.Am I just asking for problems,:confused:
     
  2. shoprat
    Joined: Dec 23, 2006
    Posts: 1,109

    shoprat
    Member Emeritus
    from Orange, CA

    Just use whatever it came with.
     
  3. rodzz2010
    Joined: Feb 8, 2010
    Posts: 54

    rodzz2010
    Member
    1. A-D Truckers

    would if they were there
     
  4. Dale Fairfax
    Joined: Jan 10, 2006
    Posts: 2,585

    Dale Fairfax
    Member Emeritus

    Grade 8 is overkill. The originals were equivalent to Grade 5.
     

  5. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    Be very careful cleaning the threads in the block. Dont use a tap, they take out too much. Use a common thread cleaner/chasser. Then, put on one head to measure the bolt length. Some of the holes are very short. On final assembly, use thread sealer on the threads, and a drop or two of oil under the head to reduce friction. Start at 30 foot pounds, in the correct pattern. Go to 45, then 50, then 50 again, then the day after first start, 50 again. The next day, do 50 again. Use three pellets in the radiator to seal up the threads from the bottom.
     
  6. rodzz2010
    Joined: Feb 8, 2010
    Posts: 54

    rodzz2010
    Member
    1. A-D Truckers

    Thanks for the help I do appreciate the advise
     
  7. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,614

    Rusty O'Toole
    Member

    Head bolts are necked down to prevent them rusting to the head. You can do yours on a lathe.
     
  8. noboD
    Joined: Jan 29, 2004
    Posts: 7,917

    noboD
    Member

    On a 1924 car I own I used B-7 threaded rod to replace the head studs. B-7 is { 4340, I think} alloy, would have to look it up. Anyway it has about the same tensile strenght as grade 8 and has worked perfect for sevral years. I used hardened washers and the stock nuts. B-7 is available from MSC, McMaster-Carr and many other places and has a much better finish and fit then standard threaded rod.
     

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