I don't know if you'd ever find a precise definition of "dialectical engine" I'm mostly just referring to the general idea of Hegelian dialectics. I've never actually read Hegel either, just Stalin and Mao. If you're interested in Hegelian dialectics specifically I don't really know where you can get started since it's infamously unreadable for people who aren't super familiar with 18th century philosophy; maybe just take a look at Hegel's wikipedia page.

Rephrasing what I meant: If you think dialectically, it's very natural to take something someone else said, and contribute by developing the dialectic: remarking contradictory data, drawing the opposite conclusion, or just generally being a contrarian. If that's how you think, it can be difficult to just think of a new meaningful contribution to discussion unprompted.

Edit: Here's a few primers on (Marxist) dialectics:

https://youtu.be/GNHzVeC7jeY

https://www.marxists.org/reference/archive/mao/selected-works/volume-1/mswv1_17.htm

https://www.marxists.org/reference/archive/stalin/works/1938/09.htm