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    Stag engine cylinder head stud removal

    Further to the other ongoing recent strings re stud removal by f100stepside(2/11/2014) and MarkShutt(4/9/2014) as an owner myself confronted by the same problem, only worse so, in that the score so far is:-
    2 studs out clean, 3 broken off and 5 corroded in and stuck tight.
    As a novice with Stag engines, I’m wanting to know why do the Stag engines have studs at all, rather than proper cylinder head bolts? The Stag engine’s own 10 cylinder head bolts usually seem to come out without any problem at all?

    #2
    Hi Tony,

    The bolts come out much easier, not because they are bolts but because they are *much* shorter. Therefore the galvanic corrosion is not on such a large surface area so you don;t have as much torque needed to break the seal as it were. When you need to clamp something using such a long shaft, then studs do no not give rise to as much inaccuracy in the torque applied because they do not allow as much twist in the shaft as a bolt would.

    Maybe I have been lucky, but I have always managed to get most of the studs out cleanly but if you are having serious issues then search on here for the "rope trick" or head removal tools as lots of methods have been found when all else fails.

    Hope that helps.

    KInd regards
    Ian

    Comment


      #3
      Someone of going to give this a try sooner or later
      http://youtu.be/RVuKML-rL0s
      John

      Comment


        #4
        I spoke to the Inductor people but they want over £500 for an ex-demo mini unit so I declined. Might try and import one from the US at some point though where they seem to be about $500
        Paul - 3 projects, 1 breaker - garage built and housing 2 white Stags. One runs, one doesn't

        Comment


          #5
          Originally posted by Tony Triumph View Post
          Further to the other ongoing recent strings re stud removal by f100stepside(2/11/2014) and MarkShutt(4/9/2014) as an owner myself confronted by the same problem, only worse so, in that the score so far is:-
          2 studs out clean, 3 broken off and 5 corroded in and stuck tight.
          As a novice with Stag engines, I’m wanting to know why do the Stag engines have studs at all, rather than proper cylinder head bolts? The Stag engine’s own 10 cylinder head bolts usually seem to come out without any problem at all?
          Hi Tony,

          That sounds just like my situation.... The two front studs came out no problem at all, one of the middle ones snapped and last week I got another one out with a bit of persistance and probably a whole heap of luck. Only six more to go!!! Plus the broken one....

          I'm just letting the studs soak in various penetrating liquids and I'm hoping that'll eventually get all of them to release. Will try heating the area around the studs with a heat gun to see if that somehow will allow the penetrating fluid to seep in a bit easier, although I have my doubts I'll get it hot enough to make any difference. As long as you're not in a rush it'll one day no doubt come good, at least that's what keeps me going.

          As for why Triumph used studs instead of normal bolts is also beyond me, no doubt there is a reason that made sense during the design process, but I personally can't see what advantage the studs would've given compared to bolts other than that it might've looked modern and hightech at the time...

          Good luck!

          Cheers,
          Joakim
          Last edited by jagorstag; 26 November 2014, 12:31.

          Comment


            #6
            Originally posted by jagorstag View Post
            Hi Tony,

            That sounds just like my situation.... The two front studs came out no problem at all, one of the middle ones snapped and last week I got another one out with a bit of persistance and probably a whole heap of luck. Only six more to go!!! Plus the broken one....

            I'm just letting the studs soak in various penetrating liquids and I'm hoping that'll eventually get all of them to release. Will try heating the area around the studs with a heat gun to see if that somehow will allow the penetrating fluid to seep in a bit easier, although I have my doubts I'll get it hot enough to make any difference. As long as you're not in a rush it'll one day no doubt come good, at least that's what keeps me going.

            As for why Triumph used studs instead of normal bolts is also beyond me, no doubt there is a reason that made sense during the design process, but I personally can't see what advantage the studs would've given compared to bolts other than that it might've looked modern and hightech at the time...

            Good luck!

            Cheers,
            Joakim
            It was Ricardo Engineering who designed the engine for SAAB (4-cylinder) and Triumph (4 and 8-cylinder). I guess they had their reasons, one of which was the idea that the heads could be removed without disturbing the camshafts. SAAB continued development of their 4-cylinder engine and designed out the long, inclined, studs and went to conventional bolts, but this required removal of the camshaft before removing the head. No big deal in hindsight as it takes much longer to remove seized studs than it does to remove a camshaft. Unfortunately Triumph didn't have the funds to do something similar with their versions of the 4-cylinder or the TV8.

            Some owners have sourced or made long bolts to replace the studs. This in itself has generated much discussion and opinion, but so far I am not aware of any long-term advantages or disadvantages.
            Dave
            1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.

            Comment


              #7
              Just one interesting fact to add:

              Although it utilises the same bolt and stud arrangement, the Dolomite Sprint appears not to suffer from the stud seizing problems that the 1854 cc Dolomite and the TR7 slant 4 engines suffer from - the same as the Stag.

              As most will know, the Sprint utilised a clever 16 valve head design, but with only one camshaft - one set of valves being operated by rockers off the back of the camshaft.

              This design (which won a British Design Council award) involved a substantial redesign of the head with the spark plugs (the first British car with small diameter tapered seat plugs) situated down deep tubes between the valves.

              Anyway, the redesign meant that the large alloy valve cover completely covered the head, including the tops of tne head bolts and studs so they were always covered in oil, when the engine was running.

              I'm sure it wasn't deliberate, but this design meant that the head studs came out pretty easily.

              Anybody fancy redesigning Stag cam covers ?

              Cheers

              Julian

              Comment


                #8
                Hi Tony
                I looked at the Heat Inductor tool it sounded just the right thing for the job,but the cost puts it way out of most peoples pocket. Maybe the Club should buy one and charge members a small fee, if it takes all the hastle and hard work from the job it's well worth it. I tried several different methods to free the studs, the best proved to be air ratchet but maybe I was a bit lucky. The two studs that were stuck fast had to be hacksawed off with the blade in my hand, a long job but it did the trick, then the broken piece came out buy hand! so it was stuck fast in the head.
                Jonathon

                Comment


                  #9
                  Thanks guys for your responses so far. I still don't feel as though we have got to the bottom of this issue as to why we have studs at all. I take Ian's point that the studs are much longer than the bolts, but stretching my own engineering knowledge to the limit, I feel that the Stag studs are introducing a lower breaking point weakness for the stud within the threaded area of the shaft by the very thread cutting action. I believe I'm right in saying that the Stag engine studs always break at a point where the thread has been cut in the shaft, having been considerable weakened at that point by the very thread cutting action needed to form the stud. The thread in the block is not seizing up or corroding in either the studs or the bolts.
                  So, I'm still thinking, long high tensile bolts would be much stronger and easier to remove for us all in the future. Tony.

                  Comment


                    #10
                    The idea of using bolts instead of studs has been raised on here a few times over the last four or five years, but I don't think the discussions ever really reached a conclusion.

                    You could try doing a search on here, but I rather fear that if you do a search for 'head bolts' or 'studs' you'll find a lot of threads

                    Cheers

                    Julian

                    Comment


                      #11
                      When the studs sieze, the weakest point is the thread at the top, and inevitably that is where it breaks. Siezing is usually caused by corrosion between head and stud, and the way to solve that problem is to use studs which are of reduced diameter along most of the shank. This gap can then be filled by a non-corrosive compound that seals the gap and helps minimise corrosion.

                      EJ Wards sell such a stud, so that's what I would buy.

                      Comment


                        #12
                        Originally posted by DJT View Post
                        It was Ricardo Engineering who designed the engine for SAAB (4-cylinder) and Triumph (4 and 8-cylinder). I guess they had their reasons, one of which was the idea that the heads could be removed without disturbing the camshafts. SAAB continued development of their 4-cylinder engine and designed out the long, inclined, studs and went to conventional bolts, but this required removal of the camshaft before removing the head. No big deal in hindsight as it takes much longer to remove seized studs than it does to remove a camshaft. Unfortunately Triumph didn't have the funds to do something similar with their versions of the 4-cylinder or the TV8.

                        Some owners have sourced or made long bolts to replace the studs. This in itself has generated much discussion and opinion, but so far I am not aware of any long-term advantages or disadvantages.
                        I thought the idea was that it speeded up production line assembly as they could shim up the cams prior to engine assembly instead of after the heads were fitted.

                        Comment


                          #13
                          Originally posted by Staggard View Post
                          I thought the idea was that it speeded up production line assembly as they could shim up the cams prior to engine assembly instead of after the heads were fitted.
                          You could well be right Graham.......
                          Dave
                          1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.

                          Comment


                            #14
                            And quicker production meant they were certain they were leaving all the casting sand in the blocks as the line went so quickly
                            Paul - 3 projects, 1 breaker - garage built and housing 2 white Stags. One runs, one doesn't

                            Comment


                              #15
                              Originally posted by Goldstar View Post
                              And quicker production meant they were certain they were leaving all the casting sand in the blocks as the line went so quickly
                              And it thus of course gave them much more time to not do any quality control either...

                              Comment

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