As said it's been covered on here many times before, the Zetec-SE which you currently have and the Zetec-E 1.8-2L are totally different engines with the only resemblance being the name.

To start with the inlet and exhaust manifolds are on opposing sides, the mounts are different, loom, ECU etc, these are just a few of many things. Not to mention you will need different suspension as the 2L is heavier.

The consensus is it's cheaper just to buy a 2L car outright, unless you have a 2L donor car parked next to it and are prepared to swap everything over.

As said just swap it for another SE.

Martin