I like the concept a lot. The deck is already quite tight but you might want to consider using cards like Retraction Helix and Future Sight.

Megalomania thanks a lot for your input. I've considered Future Sight myself in the past since the deck just so happens to play the rest of the combo pieces. It's hard for me to add a five drop though, I was already on the fence about Memory Jar. I'm curious what Retraction Helix would be used for though. Paradox engine loops?

Yeah. 5 cmc seems a bit high but with enough mana rocks I think it will not be much of a problem.

As for the Helix, yeah, it will work well with the Engine. I’ve seen several Jhoira decks which are built around it. Not sure if it suits your type of play just throwing it out there for consideration.