Engine: Description and Operation

1. General





The SUBARU engine is made from aluminum alloy and is horizontally opposed. It is a 4-stroke cycle, water-cooled, SOHC 16-valve engine. The fuel system utilizes an MFI (multiple fuel injection) design.
A summary of the major construction and function features is as follows:
- The cylinder head is a center-plug type that utilizes pentroof combustion chambers. The four-valve design is provided with two intake valves and two exhaust valves per cylinder. The intake and exhaust ports are arranged in a cross-flow design.
- The valve rocker arm has a built-in hydraulic lash adjuster which eliminates the need for valve clearance adjustment.
- A single timing belt drives two camshafts on the left and right banks and the engine coolant pump on the left bank. Belt tension is automatically adjusted by belt tension adjuster to eliminate maintenance.
- The crankshaft is supported by five bearings to provide high rigidity and strength.
- The cylinder block is made from aluminum die cast which is integrated with cast-iron cylinder liners.