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Torque Values

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  • Torque Values

    I’m searching for torque values the following:
    1. Main engine mounting bolts
    2. Prop Governor attachment studs (nuts)
    3. ​​​​​​PMags (Magnetos) attachment studs (nuts)
    I’ve downloaded the Lycoming Service Table Limits and Torque Values, but I’m well out of my depth (more questions than answers) so any information would be appreciated.

    Nev Bailey
    Christchurch, NZ

  • #2
    I used the torque values indicated in AC 41.13 for the size of the bolt I was using. Lord, Hartzell and Champion also have the torque values they specify in their specification documents as well.

    Rob Caldwell
    Lake Norman Airpark (14A), North Carolina
    EAA Chapter 309
    Model B Quick Build Kit Serial # 11B-24B / 25B
    YouTube Channel:
    1st Flight May 18, 2021


    • #3
      Didn't Bob build your engine? I think I recall there being a reference to that in one of your videos. I would ask him about the torque for the studs, but as for the engine mounts, assuming you have the elastomeric vibration isolators (Lord, Barry, etc mounts), usually the drill there is to torque them until they bottom out on the internal bushing. In other words, keep torquing until you come to a halt.


      • Nev
        Nev commented
        Editing a comment
        Good idea Mark, thanks.

    • #4
      While I have no idea what Lycoming would want on the studs of the engine - for any airframe nuts like the engine mount nuts you should torque them to the torque values in AC43.13. Mark


      • #5
        The values for the coarse threaded studs on the prop gov and the mag clamps are in my assembly manual for my titan engine, but that is at the airport and I may not get there for a week or two. If you still need it I will post it when I can. I just used the standard published values for the engine mounts.


        • #6
          I have an MT prop governor and their paperwork specifies 180-220 in-lbs for the governor mount bolts while my e-Mags specify 17 ft-lbs (204 in-lbs) for the hold-down clamp nuts. Regarding the engine mount bolts, I agree with using the standard torque value as listed AC43-13.


          • #7
            From the lycoming OH manual, table I.

            Dave B.