Product Description
MAHLE 41909.03 (.030 OVER) PISTON RING SET is an OE-quality, plasma-moly top ring kit engineered for the 2001–2004 GM 6.6L Duramax LB7. Sized at +.030" over (approx. 4.085" bore), it’s built to restore sealing, compression, and oil control on LB7 rebuilds.
- Size: +.030" over (4.0846" / 4.085" bore)
- Configuration (axial heights): 3.0 mm top / 2.0 mm second / 3.0 mm oil
- Materials & facing: Ductile-iron plasma-moly top, cast-iron second, stainless oil ring assembly (gas-nitrided expander)
- Country of origin: Brazil
Fitment
- 2001, 2002, 2003, 2004 Chevrolet Silverado 2500HD/3500 with 6.6L Duramax LB7 (VIN “1”)
- 2001, 2002, 2003, 2004 GMC Sierra 2500HD/3500 with 6.6L Duramax LB7 (VIN “1”)
Specifications
- Bore Diameter: 4.0846" (+.030")
- Top/Second/Oil Axial Heights: 3.0 mm / 2.0 mm / 3.0 mm
- Top Ring Material/Face: Ductile iron / Plasma-moly
- Second Ring Material: Cast iron
- Oil Ring Assembly: Stainless (gas-nitrided)
- UPC/GTIN: 027067460813
Cross Reference / IDs
- MAHLE / Clevite: 41909.03, 41909.030, 41909-030
- Vendor/SKU aliases: MCI41909030 (CPP)
Installation Notes
- Confirm final cylinder bore, plateau hone to the correct RA; set ring end-gap per MAHLE specs for LB7.
- Thoroughly clean cylinder walls and ring grooves; verify ring orientation and side clearance.
FAQ
Will this fit my LB7?
Yes. This .030" over set fits 2001–2004 LB7 Duramax (8th VIN digit “1”) in Silverado/Sierra 2500HD & 3500.
Is this a “file-fit” or drop-in ring?
Rings are supplied to MAHLE spec; always measure and set end-gap during assembly. Proper honing and cleaning are required.
What are the ring sizes?
3.0 mm top, 2.0 mm second, 3.0 mm oil; top ring is ductile-iron with plasma-moly facing.
Do I need new pistons?
For +.030" you’ll need matching +.030" pistons and a properly machined block. Verify clearances per MAHLE/Chevy specs.
