Mahle MS 3.905in+.005in 1.5 1.5 3.0 mm File Fit Rings

This is a Mahle file-fit piston ring set, part number 3910MS-15. These rings are designed for a 3.905 inch bore with a +.005 inch oversize. The ring groove dimensions are 1.5mm for the top and second rings, and 3.0mm for the oil ring. File-fit rings allow for precise gapping to match your specific engine build and application, which is crucial for optimal sealing and performance.

Mahle is a well-known name in engine components, and this set is built to meet the demands of engine rebuilding. The file-fit design means you'll need to carefully measure and file the end gaps to achieve the correct clearance for your pistons and cylinders. This level of adjustability is often preferred in performance or custom engine builds where precise tolerances are key to maximizing compression and minimizing oil consumption. Ensure you have the proper tools and knowledge for filing and gapping these rings before installation.

Please note that this ring set is not CARB approved and cannot be shipped to California. Always refer to your engine's service manual for specific installation instructions and recommended ring gap specifications.