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Wrong head bolts tightening sequence

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    Wrong head bolts tightening sequence

    Hi.
    I was installing the head after machining, with new gasket and bolts.
    I made a mistake during the tightening sequence: I gave the +90° to a bolt already turned instead of another; out of the sequence, I completed the tightening of the missing bolt and the others.

    The engine didn't start yet, since I'm still cleaning the components of the cooling circuit.

    Now, my question is: is it feasible and is it better to remove and then re-tighten the bolts with correct sequence and torque?

    #2
    I did it when I just installed my head, a month or two back, also. I just loosened and corrected the issue then. no cooling issue or leaking headgasket

    Comment


      #3
      so you turned that one bolt 180' (90+90)? You will probably be 100% fine. OEM bolts are TTY bolts that stretch permanently when torque is applied. Once they get loosened, they are no longer can apply the same clamping force when retightened hence one time use. I personally had bad expirience with OEM m20 head bolts and had to spend money on arp studs (should have done it in the first place). Bolt holes where cleaned, everything was lubed....and some OEM bolts were slipping when final 90' turn was applied. Basicly there was a lot of resistance to turning during about 60' (expected) and as I got closer to 90' they just slipped. It is still a mystery to me why that happened. Almost felt like threads got stripped. Threats were fine....I think TTY bolts were bending so slightly/going off center and than sprung back straight when they got closer to 90'. Nerve racking...ARP studs are just so much more precise

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        #4
        TTY bolts are weird to use. like zaq123 describes they do not inspire confidence when they are done up. I had the same experience where it does feel like the threads strip.

        Youll be right with what you have done i reckon. I would just leave it. you would have just stretched the bolt a bit more so its all good.

        I reused some TTY bolts years ago on a 4age, i didnt even know they were TTY. never had an issue for years with those installed.

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          #5
          I thought I broke on because of that weird slipping feeling. I was cussing like a fool thinking I was going to be trying to get a damn snapped bolt out but it turned out to be exactly that.

          Comment


            #6
            Once I completed the sequence, I just tightened a little more all the bolts in the right sequence, but just to have more or less the same torque on all the bolts. This is what e30davie says I guess.

            Comment


              #7
              that weird slipping feeling.
              Yeah- 8v watercooled headbolts get something like 360, and twisting those... well, it kinda makes me wanna throw up...
              It's every bolt you've ever twisted off, but it keeps going

              t
              now, sometimes I just mess with people. It's more entertaining that way. george graves

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                #8
                360deg is a long way, ive only dealt with 90 +90 or whatever it is. There really is nothing worse than the feeling of a stripped thread. Its the sensation of seeing the bolt turning, but feeling its not getting tight. Happened to me once on a brake caliper, haunts me to this day everytime I go to do up the brake caliper bolts.

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                  #9
                  Hi guys, I finally turned the key!
                  The engine started well. But... there is smoke. Smoke from the exhaust side. I think it can be normal considering all the new gaskets, the smell is as well of warmed materials. The point is that I cannot understand how long the smoke can continue and how much it can be. I work in a small garage where only that car can stay, and after few minutes in the room there was pretty much smoke.
                  The back of the car was out of the garage so it's not exhaust gas.
                  Is it normal?

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