Product Description
MAHLE 41909.04 is a complete +.040" oversize piston ring set for the 2001–2010 GM 6.6L Duramax (LB7/LLY/LBZ/LMM). Built to OE specs and pre-lapped for immediate seating, these plasma-moly rings are engineered for durability, oil control, and reliable compression on performance rebuilds.
- Oversize: +.040" (4.095" bore)
- Top ring material/face: Ductile iron, plasma-moly
- Second ring: Cast iron, chrome faced
- Oil ring: Stainless steel, gas-nitride
- Axial widths: 3.0mm / 2.0mm / 3.0mm
- Configuration: Complete engine set (all cylinders)
- Pre-lapped: Yes
Fitment
- 2001–2010 GM 6.6L Duramax LB7 / LLY / LBZ / LMM applications.
Cross Reference Numbers
- MAHLE / Clevite: 41909.04, 41909.040, 41909040
- GTIN/UPC: 027067460820
What’s Included
Complete piston ring set for all cylinders (top, second, and oil ring assemblies) matched to +.040" overbore.
FAQ
Will this fit my LB7/LLY/LBZ/LMM 6.6L Duramax?
Yes—this set fits 2001–2010 6.6L Duramax engines (LB7, LLY, LBZ, LMM).
Is this a full engine set or a single cylinder set?
It’s a complete engine set (rings for all cylinders).
Do I need to file-fit the rings?
Always measure ring end-gap in your specific cylinders and adjust if required; follow MAHLE’s installation guidelines and your machinist’s specs.
Do these require a special cylinder finish?
Use a quality plateau hone and follow MAHLE’s recommended surface finish and cleaning practices for best seating and oil control.
