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, or to 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 ...