Mahle PowerPak 99.75mm Bore Piston and Ring Kit Subaru WRX / STI EJ25 2004-2021

Part #: 930285227. Mahle's PowerPak piston assemblies are a top - notch package that combines forged pistons, piston rings, pins, and wire locks, all proven in races. The pistons are carefully hand - deburred and coated with dry phosphate. This coating offers excellent protection against ring micro - welding and pin galling during the engine's initial startup. To boost performance further, Mahle has applied its exclusive Grafal anti - friction coating to the piston skirts. The set also features low - drag rings, steel pins, and round wire locks. Specs: Mahle MS Piston Set EJ25 with 99.75mm Bore, 79.0mm Stroke, 130.4mm Rod, 23mm Pin, - 10cc, and 8.5 CR, comes as a set of 4.

Using this Mahle PowerPak piston and ring kit is straightforward. First, make sure your engine is clean and free of debris before installation. Carefully follow the installation instructions that come with the kit. During the initial startup, let the engine run smoothly for a while to allow the components to get used to each other. This helps the dry phosphate coating on the pistons do its job of protecting against ring micro - welding and pin galling. For maintenance, regularly check the engine oil level and quality. If you notice any unusual noises or performance drops, it might be time to have the engine inspected. Keep the engine in a clean environment to prevent dirt from getting into the components. Also, make sure to use high - quality engine oil to ensure the long - term performance of the piston and ring kit.