Piston Ring Set 4.245 Bore - File Fit

The Piston Ring Set 4.245 Bore - File Fit from MAHLE PISTONS is engineered for high-performance engine builders and serious mechanics who demand precision-matched components for competitive or custom applications. This file-fit ring set is purpose-built for applications requiring exact bore specifications and superior ring-to-bore clearance control. When engine performance and reliability depend on exacting tolerances, a properly fitted ring set minimizes blowby, reduces oil consumption, and optimizes compression dynamics across the full RPM range.

Manufactured from premium iron with plasma moly coating, this eight-cylinder kit features ring dimensions of 1.0 x 1.0 x 2.0 mm with standard tension characteristics that balance sealing effectiveness against ring wear and bore friction. The plasma moly surface treatment provides exceptional corrosion resistance and reduces friction during initial engine run-in, while the iron construction delivers long-term durability under sustained high-rpm and high-boost conditions. File-fit rings require professional honing and custom fitting to the specific bore during installation, ensuring optimal sealing geometry and preventing excessive side clearance that could compromise ring function.

This ring set is ideal for engine builders restoring or upgrading large-displacement eight-cylinder engines where standard off-the-shelf rings may not meet tolerance requirements or performance targets. Professionals working on marine engines, high-output automotive builds, or racing powerplants will appreciate the precision control and superior material quality MAHLE delivers. Installation requires proper honing equipment and expertise to file-fit rings to your specific bore diameter; this is not a bolt-and-go component and should only be installed by experienced technicians familiar with ring gapping and bore-to-ring clearance specifications.