* Block and Head: While both use a cast-iron block and aluminum cylinder heads, the Series III engine received revisions to the cylinder head design for improved flow and combustion. This often resulted in slightly increased power and torque, along with better fuel efficiency. Specific changes included improved porting and potentially different valve sizes or valve train components.
* Management System: The biggest difference lies in the engine management system (EMS). The Series III typically features a more advanced EMS compared to the Series II, offering better control over fuel delivery and ignition timing. This leads to smoother running, reduced emissions, and better drivability. The exact EMS used varied depending on the application and year of manufacture.
* Intake Manifold: Minor changes to the intake manifold design might be present between the two series, often complementing the improvements made to the cylinder head and EMS.
* Other Components: Minor changes in other components, such as oil pumps, might also exist between the Series II and III. These are often incremental improvements rather than fundamental redesigns.
It's crucial to note that the exact specifications varied slightly based on the vehicle application (e.g., Range Rover, Land Rover Discovery) and the year of production. Direct comparisons require specifying the precise engine codes for both Series II and Series III variants. Simply saying "Series II" or "Series III" isn't always sufficient for precise technical detail.
In summary, the Series III engine represents an evolution of the Series II, offering incremental improvements in performance, efficiency, and refinement through refinements to the head, management system, and potentially other related components. The improvements were largely evolutionary, aimed at addressing minor weaknesses and enhancing the overall engine package.
