In the attached, I did an even different method. Since no one has yet offered anything, I guess I was wrong about the more-current versions having a Tool/Feature for doing this cutaway/section-hatch thing.
In the attached, I did the sectioning and hatching in Modelspace.
>I created the initial Section object as I did previously. And dragged that new entity off to the side.
>I created another closed polyline to use for the negative of that section on the original entities. To create the thing(s) you don't see in the first Section object.
>That new Section object (the upper corner of the engine) is a Group (that's what the Section Tool automatically does). I went into that Edit Group Contents, and did a Section on the faces I wanted hatched. I used Section by 3 Points, for that.
>I copied those resultant 2D Section objects; exited out of that Group Edit; and pasted those 2D Section objects and moved them into place on my first Section object (the top parts of the engine with the corner cut away.)
>In Paperspace, inserted a Viewport, making sure I only had the Layers I wanted visible set to show.
The reason I went through a bunch of steps on this revision and the previous revision I shared is because this engine is fairly complex, so for a cutaway hatching, I wanted to be able to just use Pick_Point_Hatching.
Again, (pride) disclaimer: I made very little efforts to better organize and format this drawing file. There's a lot I would have done differently if I had drawn the initial drawing and it was for reals.