Manley Size (STD) Stroke (79mm) Bore (99.50mm Grade B) SINGLE Piston w/ Rings WRX STI EJ257 2004-2021

Part #: 612000CB - 1. Manley Subaru pistons are crafted from high - strength 2618 material. They offer a drop - in installation and match OEM Grade Range A or B bore sizes. Just pick the right grade range pistons for your engine block. Each grade range is designed with proper clearance. These pistons come with Premium Chrome Moly 0.180' wall pins, perfect for moderate boost. Included are Total Seal piston rings. The top ring is AP steel, and the second has a Napier profile for better oil control. For high - boost engines, we highly recommend installing 9310 alloy 0.210' wall wrist pins (part no. 42546).

Using these Manley pistons is quite straightforward. First, make sure to select the appropriate grade range pistons that match your engine block's requirements. When installing, they are designed for a drop - in fit, but still handle them carefully. The pistons come with Premium Chrome Moly 0.180' wall pins which are suitable for moderate boost. If you're running a high - boost engine, replace these pins with the recommended 9310 alloy 0.210' wall wrist pins (part no. 42546). As for maintenance, regularly check the piston rings. The top AP steel ring and the second Napier profile ring work together to control oil, so make sure they are in good condition. Also, keep an eye on the clearance in the grade range you've chosen. If you notice any abnormal wear or performance issues, it's a good idea to have the pistons inspected by a professional.