Cylinder Base Nuts

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      Topic for Tony & RAM came up at Q & A Session Branson convention regarding cylinder swap.
      I believe Tony stated that they used the same through bolt; but confirm that he or most shops replaced the cylinder base nuts/bolts.
      Please correct me if this was correct and that this has to do with tensile strength on subsequent use?

      I believe the TCM letter states on engine OH all are replaced but not required on single cylinder? Any thoughts.



      Continental maintenance and overhaul manuals are online at lots of good stuff on there website. Parts manuals are also online.


      The through studs would not be replaced during a single cylinder replacement. To my limited knowledge, they are only replaced at overhaul. They have interior rubber o-rings, and are quite tight into the case.

      Likewise, the cylinder base studs would not be replaced unless there was some issue. I think they are checked at overhaul for height and condition but otherwise left bedded in the case. The nuts should be replaced, and the new nut standard is 12 pt.



        Maybe you should read Mike Busch’s article in EAA June 2014 Sport Aviation on cylinder replacement and it pitfalls; titled “Cylinder Work: Be Afraid” page 26 and subtitled “It is nearly impossible to install a cylinder correctly when the engine is on the airplane”. I have been wrenching for 40+ years and I learned a lot from this article. It goes into great detail about bolt stretch, thread contamination, thread lubricants, through bolts, how to torque and how not to torque, and top overhauls in general. The importance of this cylinder change issue has been brought to the forefront because of the Superior and ECI mandatory cylinder replacement ADs and possible ADs.

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