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Technical Removing cylinder head bolts, your thoughts?:

Discussion in 'The Hokey Ass Message Board' started by c-10 simplex, May 14, 2016.

  1. c-10 simplex
    Joined: Aug 24, 2009
    Posts: 1,371

    c-10 simplex
    Member

    Should cylinder head bolts be removed in sequence and incrementally?

    Or does it not matter?

    Small block chevy with iron heads.

    Your thoughts?
     
  2. 302GMC
    Joined: Dec 15, 2005
    Posts: 8,514

    302GMC
    Member
    from Idaho

    Air gun & impact socket ...
     
    LOU WELLS likes this.
  3. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,339

    falcongeorge
    Member
    from BC

    I do it sequentially, but I dont think it makes any difference, just a habit with me. Even Im not compulsive enough to do them incrementally, I just crack 'em all with a breaker bar, then spin 'em out with a T bar and extension.
     
  4. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,561

    gimpyshotrods
    ALLIANCE MEMBER

    Impact gun, no order. Discard. Replace.
     
    Bandit Billy likes this.
  5. squirrel
    Joined: Sep 23, 2004
    Posts: 60,040

    squirrel
    Member

    I usually do them in reverse order that I tighten them. I don't know why.
     
    shawnsauto1 likes this.
  6. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,756

    Rusty O'Toole
    Member

    Doesn't matter how you take them out, it does how you put them in. Head bolts were reusable up to the early or mid 80s, since then many are one use only.
     
  7. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 16,150

    Bandit Billy
    ALLIANCE MEMBER

    I'm with Gimpy, I blast them out with the impact gun and discard them. New ARP bolts on the install.
     
    LOU WELLS and gimpyshotrods like this.
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 60,040

    squirrel
    Member

    I almost always reuse them, too. I don't work on late models much!

    I wonder why we torque them in a certain pattern?
     
  9. I was taught that we torque them in sequence to make sure that the gasket spreads correctly. It could be totally unnecessary given today's new materials in gasket construction, but I'm pretty sure I will continue to use the sequence as long as I can still put enough force to the torque wrench to make it click! ;)
     
    Last edited: May 15, 2016
  10. jcmarz
    Joined: Jan 10, 2010
    Posts: 4,631

    jcmarz
    Member
    from Chino, Ca

    I always "break" the bolts first, in the same order that they are tighten. Once the pressure is released, then I use a ratchet to remove the bolts in random order. I've always reused the same bolts on the old Chevy motors but on new motors, the head bolts should be replaced, because they can break if retorqued.
    Also, for example on a 235 Chevy 6, the torque spec for the head bolts is 90-95 ft lbs, so what I do is I torque the head in increments, starting at 30-35 ft lb.
     
  11. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,561

    gimpyshotrods
    ALLIANCE MEMBER

    Bolts are cheap. Engine failures are not.

    I will not trust a $3-14k build on 30-70 year-old bolts in unknown condition.
     
    Bandit Billy likes this.
  12. Sporty45
    Joined: Jun 1, 2015
    Posts: 1,388

    Sporty45
    Member

    That's funny! I just helped my neighbor out yesterday replacing head gaskets on his diesel pick up. Final torque was 210lbs!!! We both were pulling on the wrench, but couldn't get to click point, had to put a pipe on it to get there. Manual says not to do that, but there was no way we could get it done without one.
     
  13. stimpy
    Joined: Apr 16, 2006
    Posts: 3,546

    stimpy

    break them loose in the reverse order of tightening then remove them , inspect them and reuse them , if its a race motor it gets studs after it comes back from the machine work ( except lower end as they have to align bore it after it gets studded )
     
  14. stimpy
    Joined: Apr 16, 2006
    Posts: 3,546

    stimpy

    need to get one of my wrenches thats made for that, its 4' long and can go to 600 LBft , and its a dial type . I have a special hydraulic one we use on EMD's as the crab head nuts ( head retainer) torque out at 1900lbft the old wrench one we had was 8' long and it doesn't work well when the motor is still in the unit .
     
  15. steinauge
    Joined: Feb 28, 2014
    Posts: 1,507

    steinauge
    Member
    from 1960

    We torque headbolts in pattern to prevent warping the head casting.If you notice you will see we always start in the middle and work out toward the ends.This keeps the head casting flat on the block.I usually loosen headbolts in pattern.Some engine manufacturers are very specific about loosening incrementally and in pattern.IME those will usually be engines that have aluminum heads and not enough head bolts.
     
  16. c-10 simplex
    Joined: Aug 24, 2009
    Posts: 1,371

    c-10 simplex
    Member

    As far as reusing the bolts, how "old" is old and how new is new as far as engines/engine type?

    i'm not opposed to buying new bolts, i'm just curious. In my case, it appears that the engine has never been rebuilt.
     
  17. c-10 simplex
    Joined: Aug 24, 2009
    Posts: 1,371

    c-10 simplex
    Member

    Yes, i'm getting the impression that iron, it doesn't matter, aluminum probably does.
     
  18. stimpy
    Joined: Apr 16, 2006
    Posts: 3,546

    stimpy

    it depends alot of the condition of the shank ( nicks , rust ) and the threads , and unless you know someone who does NDT testing the only real way is to measure the length to see if they are stretching , but you have to know the length of them before they were put in . so if your worried about it , chuck them and get new ones .and use a rolled thread replacement not cut threads ..
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 60,040

    squirrel
    Member

    Look up the torque specs, if they mention turning some fraction of a turn after reaching a certain torque value, then they're probably torque to yield design, and need to be replaced.

    I trust 70 year old bolts more than I trust new stuff of unknown origin. But yeah, you need to inspect them and make some judgements based on experience.
     
    34toddster, Moriarity and 302GMC like this.
  20. Canus
    Joined: Apr 16, 2011
    Posts: 102

    Canus
    Member

    For squirrel, The reason heads bolts are torqued from the inside out is to allow the gasket to expand outward as we tourque. If we were to torque the outside bolts first we would "trap" the gasket thus not allowing it to spread.
     
    Atwater Mike likes this.
  21. c-10 simplex
    Joined: Aug 24, 2009
    Posts: 1,371

    c-10 simplex
    Member


    Ahhhh..........I.C.
     
  22. squirrel
    Joined: Sep 23, 2004
    Posts: 60,040

    squirrel
    Member

    Sounds a bit strange to me....I once asked my gaskets if they were worried about feeling trapped, and they didn't seem to concerned about it.
     
  23. indyjps
    Joined: Feb 21, 2007
    Posts: 5,397

    indyjps
    Member

    I break them loose by hand, half a turn, mostly to be sure they're breaking loose and not seized, then buzz them out with impact. I mainly build sbc's and reuse head bolts unless I see something wrong. Buy bolts on anything hi-po.
     
  24. Canus
    Joined: Apr 16, 2011
    Posts: 102

    Canus
    Member

    All gaskets must "flow" in order to fill the gaps in the machined surfaces they are in contact with. Obviously rubber or cork gaskets will fill larger grooves whereas copper or steel gaskets (like head gaskets) can only fill much smaller grooves. By torquing from the insde out the gasket "flow" is allowed to work outward as we tighten thus not being "trapped" causing the gasket to bunch up, thus forcing the mating surfaces apart and possibly causing a leak.
     
  25. Canus
    Joined: Apr 16, 2011
    Posts: 102

    Canus
    Member

    ALL bolted connections should be detensioned in the reverse order they were torqued.
     
    falcongeorge likes this.
  26. Atwater Mike
    Joined: May 31, 2002
    Posts: 11,618

    Atwater Mike
    Member

    S.A.E. dictated 'bolt stretch' to ascertain steady 'clamping' during the life of the gasket; torque specs to 'guarantee' tightness when hot and when cold.
    Do A.R.P. bolts have the same elasticity specs as factory O.E.M.?
    ARP spec sheets liken con rod bolts to possess the hardness of the Hubs of Hades. 'Bolt Stretch? Not on this train...'

    When the 'art of Angle Torquing' came about (BMW factory specs) I took it as ludicrous. Two of our apprentices were convicted of pulling studs @ 30 degrees. A long probationary period ensued...
    Parts Dep't was optimistic they'd make a killing in s**** metal for the stretched bolts that were replaced with every head gasket replacement.
    I longed for the 'good old days'...
     
  27. buffaloracer
    Joined: Aug 22, 2004
    Posts: 823

    buffaloracer
    Member
    from kansas

    I give about a quarter turn in reverse order and then remove them in the same order. Had an old shop teacher that worked for Mercedes and they removed them with an impact. Probably doesn't matter on removal but I don't think I'll change.
     
  28. seb fontana
    Joined: Sep 1, 2005
    Posts: 9,214

    seb fontana
    Member
    from ct

    We don't need head bolts![​IMG]
     
  29. Gene Boul
    Joined: Feb 9, 2006
    Posts: 805

    Gene Boul

    In the case of a SBC the only bad thing you can do is loosen all bolts except bottom row! You know the ones hidden by the exhaust!
     
  30. squirrel
    Joined: Sep 23, 2004
    Posts: 60,040

    squirrel
    Member

    first time I took heads off a SBC, it was an old 283 before PCV, the heads were covered with sludge, I was 14 years old...I was prying for a while before I looked and found those other two bolts near the ends, way down in there. Didn't break anything, I wasn't strong enough to.
     

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