Here's a breakdown of the challenges:
* Engine Mounts: The engine block and transmission mount locations are completely different. You'll need custom engine mounts fabricated.
* Transmission: The 2002 DOHC engine likely used a different transmission than the 1996 SOHC. You might need to swap the transmission as well, leading to further compatibility issues with the driveshaft, axles, and differential. Even if the transmission *appears* compatible, the bellhousing bolt pattern almost certainly won't match.
* Wiring Harness: The wiring harnesses are completely incompatible. You'll need to extensively rewire the car, possibly requiring a custom harness built or significant splicing and modification of both harnesses. This includes the computer (ECU), sensors, and all electrical connections.
* ECU (Engine Control Unit): The 2002 ECU is not compatible with the 1996 car's systems. You'll need the 2002 ECU, and potentially a way to adapt its signals to the older car's instrumentation and other systems.
* Exhaust System: The exhaust manifold and system will need significant modification or replacement due to the different engine design and mounting location.
* Cooling System: The cooling system components, including the radiator, hoses, and thermostat, may not be compatible.
* Fuel System: The fuel injectors, fuel rail, and fuel pump may require modification or replacement to match the new engine.
* Bodywork: Depending on the size and location of the DOHC engine, you may need to modify the engine bay to accommodate it.
* Driveshaft: The driveshaft length is almost certainly incorrect and will likely need modification or replacement.
In short: This swap is not a beginner project. It requires advanced mechanical skills, significant fabrication abilities (welding, metalworking), electrical knowledge, and a deep understanding of automotive systems. You'll likely need access to a workshop with specialized tools.
Alternatives: Instead of this complex swap, consider these options:
* Rebuild the original engine: A rebuild of the 1.9L SOHC engine is far simpler and more cost-effective.
* Find a used replacement 1.9L engine: This would be a much more straightforward swap.
* Find a compatible engine from a later-model Saturn: Look for a similar-year Saturn with a slightly more powerful engine that is a more direct bolt-in replacement.
Unless you have extensive experience with engine swaps and fabrication, this DOHC swap is highly discouraged. The time, cost, and complexity will likely far exceed the potential benefits.
