Product Description
MAHLE 929969355 MONOTHERM FORGED STEEL RACE PISTON SET brings heavy-duty forged-steel piston technology to your late 5.9L Cummins build. Designed for extreme cylinder pressures and heat, these one-piece Monotherm pistons deliver unmatched strength and ring stability for competition use. Price is for a complete set of 6 pistons.
- Bore: 4.055" (+0.040")
- Stroke reference: 4.724"
- Compression Ratio: 16.1:1
- Compression Height: 2.804"
- Pin Diameter/Style: 1.575" floating
- Crown Volume: −48.6 cc
- Approx. Piston Mass: 1706 g
- Includes: pistons, ring set (MAHLE S42170), pins, and locks
Engineered for 04.5–07 “late” 5.9L common-rail injectors; MAHLE notes a reduced compression height vs. early CR to manage CR and valve pocketing for performance builds.
Fitment
- 2004.5, 2005, 2006, 2007 Dodge Ram 2500/3500 with 5.9L Cummins (late common-rail, 24-valve)
Cross Reference / Related
- MAHLE Part No.: 929969355
- Ring Set: S42170 (standard; oversizes available: S42170.020, S42170.040)
- MAHLE Diesel PowerPak / Monotherm documentation (application notes and spec overview)
What’s Included
Six forged-steel Monotherm pistons, rings, pins, and locks for a complete set.
FAQ
Is this a full engine set?
Yes. Price is for a complete set of 6 pistons with rings, pins, and locks.
Will these fit my 2003?
These are engineered for 2004.5–2007 late 5.9L common-rail applications. If you’re building a 2003–early-2004, consult MAHLE for the correct part or conversion details.
Are the rings included and which set?
Yes—MAHLE S42170 ring set is included with this kit.
Street-driven friendly?
Monotherm forged-steel pistons are targeted at high-output/competition builds. For mixed street use, verify compression, tuning, and clearances with your engine builder.
What compression ratio will I see?
Nominal is 16.1:1 with MAHLE’s stated assumptions (0.010" piston protrusion and 0.060" x 4.150" head gasket). Actual CR depends on deck height, gasket, and machining.
