Mahle PowerPak 99.5mm Bore Piston and Ring Kit Subaru WRX / STI EJ25 2004-2021

Part #: 930285117. Mahle's PowerPak piston assemblies are a one - stop solution for high - performance needs. It comes with forged pistons, piston rings, pins, and wire locks. The hand - deburred pistons are dry phosphate - coated to prevent ring micro - welding and pin galling at startup. Mahle also added its special Grafal anti - friction coating to the piston skirts for better performance. Low drag rings, steel pins, and round wire locks make up this proven package. Specs: Bore Size 99.5mm, Wrist Pin Size 23.0mm, Piston Material 2618 Forged Aluminum, Compression Height 30.7mm, Piston Ring Size 1.2 1.2 2.8mm, Piston Type Dish - 22cc, Crankshaft Stroke 79.0mm.

Using this Mahle piston and ring kit is straightforward. First, make sure your engine is clean and ready for installation. Carefully place the pistons into the cylinders, following the correct orientation. The pins and wire locks should be installed securely. When starting the engine for the first time, take it easy for a short period to let the components settle in. As for maintenance, regularly check the engine oil for any signs of debris. Also, keep an eye on the engine temperature to ensure it doesn't overheat. If you notice any unusual noises or performance issues, have your engine inspected by a professional.