Forged Steel Rocker Arm with Corrosion-Resistant Coating and Hardened Contact Pad for Isuzu 4JJ1 Engine

The Rocker Arm (OEM Numbers: 8-98025059-4 / 8980250594) is a premium-quality, direct replacement valvetrain component designed for Isuzu NKR and NPR series medium-duty trucks equipped with the 4JJ1 diesel engine.

Function: Transfers motion from the camshaft or pushrod to the valve stem, opening and closing the engine valves at precise timing. Ensures efficient combustion and quiet valvetrain operation for Isuzu 4JJ1 diesel engines.

• OE Quality: Manufactured to Isuzu dimensional and material specifications for perfect fit and reliable valve actuation
• Hardened Contact Pad: Wear-resistant surface reduces friction and extends service life
• Precision Pivot Bore: Smooth operation on the rocker shaft
• Lightweight yet Strong: Forged construction minimizes reciprocating mass
• Restores Valvetrain Performance: Eliminates tapping noise, uneven valve lift, and power loss
• Direct Replacement: Matches OE dimensions - simple installation
• Cost-Effective: Affordable alternative to genuine OEM rocker arms

This rocker arm is specifically designed for Isuzu NKR and NPR trucks with 4JJ1 engine.

• ISUZU NKR (NKR55, NKR57, NKR59, NKR71 with 4JJ1)
• ISUZU NPR (NPR66, NPR70, NPR71, NPR75 with 4JJ1)
• Also fits Isuzu D-MAX, MU-X with 4JJ1 (verify)

• 4-Cylinder, Inline Diesel, DOHC, Common Rail, Turbocharged
• Displacement: 3.0L (2999cc)

Installation steps (overview for OHV engine):

1. Remove valve cover and any related components
2. Remove the rocker shaft assembly or individual rocker arm (depending on design)
3. Inspect the rocker shaft and pushrod for wear
4. Lubricate the new rocker arm's pivot bore and pad with engine assembly lube
5. Install the new rocker arm onto the shaft or pedestal. Ensure proper orientation (intake/exhaust)
6. Torque the rocker arm shaft bolts or adjustment nut to specification
7. Adjust valve lash to OE specification (typically 0.25-0.35mm cold for 4JJ1)
8. Install new valve cover gasket and reassemble
9. Start engine and check for abnormal noise
10. Re-check valve lash after warm-up if required

• Material Verification: Forged steel alloy composition and hardness tested
• Dimensional Inspection: Pad radius, pivot bore diameter, and overall length verified
• Hardness Testing: Pad hardness (HRC 50-55) and core hardness checked
• Visual Inspection: 100% checked for forging defects, burrs, or surface flaws
• Packaged Safely: Wrapped in protective oil paper, sealed in plastic bag, boxed with foam

• Neutral export packing or customized packaging available
• Carton or wooden case for safe transportation
• Fast delivery for stock items
• Shipping by Express Air or Sea

For pricing, availability, or bulk purchase of the Rocker Arm 8-98025059-4 For Isuzu 4JJ1 NKR NPR Engine 8980250594 Isuzu Truck Spare Parts, please contact our sales team for a competitive quote and expert technical support.