Product Description
MAHLE 41909.02 (.020 over) complete piston ring set for the 2001–2010 GM 6.6L Duramax (LB7/LLY/LBZ/LMM). Rings are pre-lapped for immediate seating and built to OE specs for reliable sealing and long service life. Top ring is ductile iron with plasma-moly face; second ring is cast iron; oil ring assembly is GNS. Sold as a complete engine set.
- Bore: ~4.075 in (4.0748 in)
- Oversize: .020 in
- Construction: Ductile-iron moly top, cast-iron second, GNS oil ring
- GTIN/UPC: 027067460806
- MPN variants seen: 41909.02 / 41909.020 / 41909020
Fitment
- 2001–2010 Chevrolet Silverado 2500HD/3500HD • GMC Sierra 2500HD/3500HD
- 2003–2009 Chevrolet Kodiak 4500/5500 • GMC TopKick 4500/5500
- 2006–2010 Chevrolet Express 2500/3500 • GMC Savana 2500/3500 (6.6L)
- 2006 Hummer H1 Alpha 6.6L Duramax
- Engine RPO codes: LB7, LLY, LBZ, LMM (VIN codes 1, 2, 6, D)
Cross Reference & Related Sizes
- MAHLE: 41909 (STD), 41909.01 (.010), 41909.02 (.020), 41909.03 (.030), 41909.04 (.040)
- GM OE: 97386951 (standard-bore single-piston ring set; listed for reference)
- Clevite/MAHLE: 41909.020 (retailer format)
What’s Included
Complete engine set of piston rings for all eight cylinders (file-fit as required). Pistons not included.
Install Notes
Verify bore size, piston-to-wall clearance, and end-gaps. Follow MAHLE specifications for ring orientation and gaps. Hone finish should match ring material and intended use.
FAQ
Will these rings fit my LB7/LLY/LBZ/LMM?
Yes. This .020-over set fits 2001–2010 6.6L Duramax LB7, LLY, LBZ, and LMM applications listed above.
Are the rings pre-lapped / do they require break-in?
They’re pre-lapped so they seat quickly and do not require a traditional break-in.
Is this a full engine set?
Yes, this is a complete set for all eight cylinders.
What’s the bore size for .020 over?
Approximately 4.075" (4.0748" nominal).
Do I need to check ring gaps?
Yes. Always check and set gaps to your build’s specs (street, tow, or performance).
