Subaru’s EJ257 was a turbocharged, 2. The EJ257 engine had a wine corks for leg cramps-cast aluminium block with 99.
5 mm bores and a 79. 0 mm stroke for a capacity of 2457 cc. The EJ257 engine had a semi-closed deck design whereby the cylinder walls were attached to the black at the twelve, three, six and nine o’clock positions. For the EJ257 engine, the crankshaft was supported by five main bearings and, like other EJ Phase II engines, the crankshaft thrust bearing was positioned at the rear of the crankshaft. The connecting rods were made from forged high carbon steel, while big end cap dowel pins and set screws were used for accurate mating.
The EJ257 engine had cast aluminium pistons with an Alumite coating for the piston head and ring grooves, and a molybdenum coating for the piston skirts. The EJ257 engine had a die-cast aluminium cylinder head that was mounted on a head gasket which consisted of three stainless steel sheet layers. The single timing belt had round profile teeth for quiet operation and was made from a strong flexible core wire, wear resistant canvas and heat resistant rubber. Each camshaft was supported at three journals, held in position by three camshaft caps and had a flange which fitted the corresponding groove in the cylinder head to receive thrust forces. The EJ257 engine had parallel flow cooling system whereby coolant flowed into the block under pressure, crossed the gasket to the cylinder head and then passed through holes adjacent to each cylinder. The intake valves had hollow stems to reduce mass and inertia, while the exhaust valve stems were filled with sodium. At high temperatures, the sodium would liquefy and its motion within the stem would effectively transfer heat from the valve head to the valve stem, contributing to faster cooling of the valve head.