Engine swap

An engine swap is the process of removing a car's original engine and replacing it with another.

This is done either because of failure, or to install a different engine, usually one that is more modern and so more efficient, this may make it more powerful and or economical. Older engines may have a shortage of spare parts and so a modern replacement may be more easily and cheaply maintained. Swapping to a diesel engine for improved fuel economy is a long established practice, with modern high efficiency and torque diesel engines this does not necessarily mean a reduction in performance associated with older diesel engine swaps. For the particular application of off-road vehicles the high torque at low speed of turbo diesels combined with good fuel economy makes these conversions particularly effective. Older non-electronic fuel injection diesels were well known for their reliability especially in wet conditions.

An engine swap can either be to another engine intended to work in the car by the manufacturer, or one totally different. The former is much simpler than the latter. Fitting an engine into a car that was never intended to accept it may require much work – modifying the car to fit the engine, modifying the engine to fit the car, and building custom engine mounts and transmission bellhousing adaptors to interface them along with a custom built driveshaft. Some small businesses build conversion kits for engine swaps, such as the Fiat Twin cam into a Morris Minor or similar.