Overview of Engineering Principles incorporated in Technic LEGO sets
This depends on how deep engineering principles do you wish to teach. For simpler, shallower things, like the inherent stability of a triangle based construction versus a square based, the crawler crane already offers a lot: the relation between force and leverage, skid steering, gearing, pulleys, gearboxes, electronics. Pneumatics and shock absorbers are missing from this set, but you can get some pneumatic parts from the 42008 Service truck.

For advanced concepts like Ackermann steering, Camber, caster and toe it would be hard to find official models to demonstrate, but you can always build simple models to display one or more of these features.

There are a few other things that I can think of, like fiber optics, but these are really hard to find nowadays.

Of course besides mechanical engineering there is also computer engineering, for which the Mindstorms sets offer an admittedly expensive introduction.