What do you have to do to remove a 1.6 liter engine from your 2 door 1991 sentra and replace it with a 2.0 liter?

To remove the 1.6-liter engine from your 1991 Sentra and replace it with a 2.0-liter engine, you need to start by disconnecting the battery and draining the fluids. Then, remove the necessary components such as the intake and exhaust manifolds, wiring harness, and any connections to the transmission. After lifting the engine out using an engine hoist, you can install the new 2.0-liter engine by reversing the removal steps, ensuring all connections and mounts are secure. Finally, refill fluids and reconnect the battery before starting the engine.