Mahle Rings Performance Steel Napier THM-13 4.075 x .043 .135 RW Plain Ring Set

Mahle OE Piston Rings THM-13 are a steel Napier ring set designed for a 4.075 inch bore. These rings are built to help manage oil consumption and maintain proper seal between the piston and cylinder wall. The Napier hook design on the second ring is a notable feature that helps scrape oil from the cylinder wall during the piston's downstroke, contributing to improved oil control.

This set uses a .043 inch top ring thickness and a .135 inch oil ring width, common dimensions for many performance engine builds. The steel construction offers good durability for these applications. When rebuilding an engine, ensuring you have a good set of piston rings is crucial for proper compression and long-term engine health.