Mahle 2243851WR OE Piston Set w/Rings STD 2008-2010 Ford 6.4L Powerstroke Set/8

Vehicle Fitment

• 2008-2010 Ford F-250 Super Duty (6.4L Power Stroke V8 Diesel, XL, XLT, Lariat, King Ranch, FX4, Harley-Davidson Edition, 2WD/4WD)
• 2008-2010 Ford F-350 Super Duty (6.4L Power Stroke V8 Diesel, XL, XLT, Lariat, King Ranch, FX4, Harley-Davidson Edition, 2WD/4WD)
• 2008-2010 Ford F-450 Super Duty (6.4L Power Stroke V8 Diesel, XL, XLT, Lariat, King Ranch, 2WD/4WD)
• 2008-2010 Ford F-550 Super Duty (6.4L Power Stroke V8 Diesel, XL, XLT, 2WD/4WD)
• Navistar MaxxForce 7 (6.4L V8 Diesel - commercial vehicle applications sharing the Power Stroke platform)

Fitment Notes

• Standard bore (STD) - fits cylinders at the original factory bore diameter of 3.870 in. (98.30mm); cylinders must be measured and confirmed at standard bore before installation; if cylinders are worn or scored, oversize variants (.25MM, .50MM, .75MM) are available
• Rings are included (WR suffix) - complete piston ring set pre-installed; no separate ring purchase required for standard bore rebuilds
• This is NOT a remachined OEM piston - it is a purpose-designed Mahle replacement with a redesigned combustion bowl and center hump intended to address the OEM piston cracking failures common in the 6.4L Power Stroke
• Sold as a set of 8 - one complete set covers all cylinders of the V8 engine; some retailers price per piston
• Consult your machine shop or engine builder to confirm cylinder bore measurements and proper piston-to-wall clearance before installation
• WARNING: Not legal for sale or use in California (shipping restrictions apply)
• Professional engine builder installation required

Features

• MaxxForce 7 designation - Mahle's purpose-built replacement piston for the 6.4L Power Stroke / Navistar MaxxForce 7 engine, designed specifically to eliminate the OEM piston cracking failures that are common in this application under heat cycling, high EGTs, and loaded operation
• Redesigned combustion bowl with reinforced center hump provides greater structural rigidity under elevated cylinder pressures compared to the factory piston - a targeted engineering improvement over the OEM design
• Steel insert in the top ring groove maintains ring land integrity and prevents the ring groove deformation that contributes to OEM piston failures under sustained high-temperature operation
• Cast aluminum construction with expansion-controlled skirt geometry maintains precise piston-to-wall clearances across operating temperature ranges, reducing engine noise, wear, and oil consumption
• Compensated ring grooves ensure proper ring loading, tension, and oil control under the high cylinder pressures of the 16.5:1 compression turbocharged diesel
• Standard bore (3.870 in. / 98.30mm) - drop-in fit for unmachined blocks at standard bore; no boring or honing required if cylinders are within standard bore spec
• Piston ring set included (WR) - eliminates the need to source separate ring sets for a complete standard-bore rebuild
• OE form, fit, and function - built by Mahle, the world's largest OE piston manufacturer, to factory dimensional specifications for the 6.4L Power Stroke application
• Backed by a 1-year warranty

Specifications

• Application: 2008-2010 Ford 6.4L Power Stroke / Navistar MaxxForce 7 (V8 Diesel)
• Bore Size: 3.870 in. (98.300mm) - Standard
• Stroke: 4.130 in. (Stock)
• Compression Ratio: 16.5:1
• Piston Style: Dish with Single Valve Relief
• Material: Cast Aluminum with Steel Top Ring Groove Insert
• Skirt Type: Expansion-Controlled
• Ring Grooves: Compensated
• Wrist Pin Style: Press-Fit or Floating
• Rings Included: Yes (Complete Ring Set)
• Quantity: Set of 8
• Warranty: 1 Year

Included Components

• 8x Mahle OE-grade cast aluminum pistons with steel ring groove insert (Standard bore, 6.4L Power Stroke)
• 8x Complete piston ring sets (top compression ring, second compression ring, oil control ring assembly)
• 8x Wrist pins
• 8x Wrist pin retaining clips

Product Description

The Mahle 2243851WR (224-3851WR) is a complete set of eight MaxxForce 7 designation OE-grade pistons with rings for the 2008-2010 Ford F-250 through F-550 Super Duty equipped with the 6.4L Power Stroke V8 diesel engine. Unlike a conventional OEM replacement, the 224-3851WR is not a remachined stock piston - it is a purpose-engineered Mahle replacement designed to directly address the well-documented OEM piston cracking failures in this engine. The factory 6.4L Power Stroke pistons are susceptible to cracking in the combustion bowl under sustained high heat, heavy towing loads, and EGT spikes. Mahle's redesigned combustion bowl features a reinforced center hump that adds structural rigidity in the most thermally stressed area of the piston crown, significantly improving durability under real-world operating conditions.

The pistons are cast from aluminum with a steel insert in the top ring groove to prevent ring groove deformation and maintain ring seal integrity over the life of the engine. Mahle's expansion-controlled skirt geometry ensures the piston maintains proper clearance to the cylinder wall across the full operating temperature range, while compensated ring grooves provide consistent ring loading and oil control under the 16.5:1 compression ratio of the turbocharged Power Stroke. The standard bore (STD) designation means these pistons are sized for unmachined cylinders at the factory bore of 3.870 in. (98.30mm). Measure your cylinders before ordering - oversize variants (.25MM, .50MM, .75MM) are available for bored or worn applications.

This set includes all eight pistons, complete ring sets, wrist pins, and retaining clips - everything needed for a full standard-bore engine rebuild without additional ring purchases. Sold as a complete set of 8, backed by a 1-year warranty. Note: This product is not legal for sale or use in California. Professional installation by a qualified diesel engine builder is required.