Mahle 51870CP Plain Piston Ring Set for 1996-2006 Jeep 4.0L L6 Cherokee Wrangler

Vehicle Fitment

• 1996-2001 Jeep Cherokee XJ (4.0L L6, OHV, 242ci, RWD/4WD)
• 1996-2004 Jeep Grand Cherokee ZJ/WJ (4.0L L6, OHV, 242ci, RWD/4WD)
• 1997-2006 Jeep Wrangler TJ (4.0L L6, OHV, 242ci, 4WD)
• 1996-2002 Dodge Truck (4.0L L6, OHV, 242ci, RWD/4WD)

Fitment Notes

• Fits standard (STD) bore of 3.875 in. (98.43 mm) only - measure bore before ordering; oversize variants available (.020, .030, .040, .060)
• Plain (uncoated) top ring - OE replacement spec for the Jeep AMC 4.0L 242ci inline-six
• Does not fit 1987-1995 Jeep 4.0L applications using an earlier block variant - verify engine casting before ordering
• Does not fit Jeep 4.2L (258ci) - different bore and ring package; use appropriate 4.2L ring set
• Sold as 6 sets (one complete set per cylinder for the 6-cylinder engine)

Features

• Cast iron top compression ring (RF-10PF) with plasma-moly face for fast break-in and reduced wear
• Cast iron second ring (RBT-10) with reverse barrel twist for superior groove side sealing
• CP-20 stainless steel oil ring assembly with exclusive 20-degree ear angle for maximum cylinder wall side seal
• Shallow groove CP-20 oil ring - matches OE shallow groove specification of the Jeep 4.0L engine
• Pre-lapped finish for immediate seating and minimal break-in time
• Optimized ring tension balances friction reduction with long-term oil control
• OE form, fit, and function - direct drop-in replacement for the factory ring set
• Ring materials and coatings engineered specifically for the high-mileage, off-road demands of the Jeep 4.0L

Specifications

• Bore Size: 3.875 in. (98.43 mm) - Standard
• Top Compression Ring Thickness: 1.5 mm - Cast Iron, RF-10PF
• Second Ring Thickness: 1.5 mm - Cast Iron, RBT-10 Reverse Barrel Twist
• Oil Ring Width: 4.0 mm - Stainless Steel, CP-20 Shallow Groove
• Engine Type: L6 (6-Cylinder), OHV
• Compatible Engine: Jeep AMC 4.0L (242ci) Inline-Six
• Ring Coating: Plain (Uncoated top ring; chrome oil ring rails)
• Quantity: 6 sets (1 complete set per cylinder)

Included Components

• 6x Top Compression Ring (cast iron, RF-10PF, 1.5 mm)
• 6x Second Compression Ring (cast iron, RBT-10 reverse barrel twist, 1.5 mm)
• 6x CP-20 Oil Ring Assembly (stainless steel, shallow groove, 4.0 mm)

Product Description

The Mahle 51870CP is a standard OE replacement plain piston ring set for the Jeep AMC 4.0L (242ci) inline-six engine found in the 1996-2006 Cherokee XJ, Grand Cherokee ZJ/WJ, and Wrangler TJ, as well as 1996-2002 Dodge Truck applications equipped with the same engine. This plain-finish ring set matches the OE specification and is the correct replacement for stock engine rebuilds at standard 3.875" bore. The cast iron top and second compression rings combined with the CP-20 shallow-groove stainless steel oil ring assembly deliver reliable combustion sealing and oil control suited to the off-road and daily-driver demands the 4.0L inline-six is known for.

All 6 cylinder sets are included to service the complete inline-six engine. Always measure bore before ordering - this set is for standard bore only, and oversize variants are available separately in .020, .030, .040, and .060 for bored-out engines. For engines running higher cylinder pressures or performance builds, consider the plasma-moly Mahle 41870CP as an upgrade alternative. This set does not fit the earlier Jeep 4.2L (258ci) engine, which uses a different bore and ring package.