Mahle Rings Performance Napier THM-13 3.937 x 1.2MM .135inRW Plain Ring Set

When you're rebuilding the top end of your engine, getting the piston rings seated correctly is crucial for compression and oil control. This Mahle Performance Napier ring set is designed for a 3.937-inch bore, giving you a solid option for your rebuild.

Mahle is a well-known name in engine components, and this ring set features a Napier-style top ring. The Napier hook design helps the top ring break free from the cylinder wall, which can improve oil drainage and reduce the chance of sticking, especially in demanding applications. The rings are 1.2mm thick, with a 0.135-inch ring width, fitting standard groove dimensions for many applications. They are made from durable materials to hold up under operating conditions.

This set is intended for specific engine builds where precise ring sizing and a Napier-style top ring are beneficial. Always ensure you have the correct bore size and ring groove dimensions before ordering.