Rocker Arm Assembly 3052170 3047479 | Verified Fitment for Cummins N14

Verified Cross-Reference — Rocker Arm Assembly 3052170 and 3047479 mapped against Cummins NT855, N14 and John Deere 6810 serial ranges before dispatch.

Technical Specifications

Application Suitability

Why Superseded Numbers Create Fitment Traps

Rocker Arm Assembly 3052170 3047479 cross reference fitment demands serial-level verification, not just part number matching.

A worn nameplate on a Cummins NT855 often leaves only the engine model visible, yet within that single model designation exist multiple valve train configurations that accept physically different rocker arms. Part number 3052170 was superseded by 3047479 in later production runs, and the intermediate designation 3052170rx covers remanufactured exchange units — a distinction that matters when mating surfaces and pivot bore tolerances differ between new-cast and reconditioned assemblies. I have seen repair centres order six rocker arms based on a single cross-reference table, only to find that two of the six engines on their bench required a different contact angle geometry. The cost is never just the return shipping; it is the machine sitting idle while the correct part crosses an ocean. [NEED_CITE: valve train geometry variation across Cummins 855-series engine generations]

Serial Range Coverage and Variant Identification

The Cummins 855-family and its John Deere derivatives span decades of production, with running changes to rocker arm pivot location, adjuster screw thread pitch, and roller-to-valve contact radius. Rocker Arm Assembly 3052170 3047479 cross reference fitment requires confirming the engine serial number falls within the documented range for this specific casting and machining profile. Engines built before the mid-production revision may carry a different base number that is not mechanically interchangeable despite appearing in the same parts catalog page.

Providing the full engine serial number — typically stamped on the data plate riveted to the rocker cover or block — allows verification against the build record. Where the nameplate is painted over, corroded, or missing, the machine model and approximate year of manufacture can narrow the field to two or three candidate configurations, and a sample unit can be dispatched for physical trial before bulk commitment.

Interface Geometry and Cross-Reference Validation

The pivot bore diameter, maintained to ±0.01 mm tolerance on this assembly, determines the rocker arm's position on the shaft and therefore the sweep angle of the valve contact pad across the valve stem tip. A deviation here shifts the contact pattern toward the edge of the stem, accelerating wear on both the rocker pad and the valve guide. The phosphated surface treatment provides break-in lubricity during initial running hours, reducing scuffing risk on the pivot bore and adjuster thread interfaces. [NEED_CITE: valve train contact pattern analysis and rocker arm geometry tolerances]

Cross-referencing between 3052170, 3052170rx, and 3047479 involves more than confirming the numbers appear together in a supplier's interchange list. The dimensional envelope, mounting hole spacing, and adjuster screw engagement length must all be checked against the specific engine build sheet to confirm the part will install and function correctly without modification.

Material and Hardness Specifications Decoded

Forged 42CrMo alloy steel provides the core structural requirement for a rocker arm operating under repeated cyclic loading from the camshaft lobe through the pushrod. The chromium-molybdenum composition delivers through-hardening capability, meaning the surface hardness reading of HRC 48–52 extends below the contact surface rather than existing as a shallow case that wears through during service. This matters in high-hour mining haul truck and port loader applications where valve train components see continuous operation under heavy load.

The forging process aligns the grain structure along the rocker arm's load path from pivot bore to valve contact pad, resisting the bending stress that would initiate fatigue cracking in a cast equivalent. Phosphated finish serves a dual purpose: corrosion protection during storage and transport, and a sacrificial lubricating layer that prevents metal-to-metal contact during the critical first minutes of operation before full oil pressure builds at the rocker shaft. [NEED_CITE: forging versus casting fatigue performance in valve train components]

The Hidden Cost of Unverified Fitment

Ordering a rocker arm that matches the part number but not the engine variant creates a cascade of delays that compounds with each day the machine remains non-operational. In mining and port applications running 24/7 schedules, a machine standing idle while a replacement part is sourced and shipped represents lost production volume that far exceeds the component cost. The forced-fit scenario — where an incorrect rocker arm is installed because it appears to bolt on — produces misaligned valve contact, accelerated stem and guide wear, and typically manifests as valve float or compression loss within the first few hundred operating hours. [NEED_CITE: valve train misalignment consequences in heavy-duty diesel engines]

Why Procurement Through This Channel Works

Selected production lines run in our own Guangzhou facility, while complementary components are sourced from ISO-certified manufacturing partners — both channels carry identical quality control standards and the same six-month warranty, meaning a single accountability point regardless of which line produced the part. Eight product categories spanning engine, hydraulic, electrical, undercarriage, cabin, seal kits, tools, and general spares allow a complete valve train overhaul list to ship under one consignment from one account, eliminating the coordination burden of managing separate suppliers for rocker arms, gaskets, and seal kits. Minimum order is one piece, so emergency single-unit purchases proceed without MOQ barriers. Guangzhou warehouse stock on common-fitment items supports fast dispatch, while part identification from a part number, machine model, photograph, or nameplate image resolves ambiguous fitment situations. Cross-reference verification covers superseded numbers and alternate references, and sample supply is available for physical fitment confirmation before bulk commitment, removing the trial-and-error risk from fleet-standardisation projects.

Documentation & Verification

• Commercial invoice and packing list itemising each rocker arm assembly and associated part references
• Cross-reference sheet mapping 3052170, 3052170rx, 3047479 to confirmed engine serial ranges (reference only)
• Dimensional inspection record covering pivot bore tolerance and contact geometry
• Warranty terms documenting coverage scope and claim procedure for manufacturing defects
• Packing photographs verifying condition and protection before dispatch
• HS code and customs classification support for import clearance documentation

Fitment Check Before Installation

• Confirm pivot bore slides onto rocker shaft without binding and without perceptible lateral play
• Compare adjuster screw thread pitch and length against removed original unit before assembly
• Verify valve contact pad sweep pattern centres on valve stem tip using marking compound
• Check rocker arm mounting bolt hole spacing matches cylinder head boss pattern
• Rotate engine by hand through full valve cycle to confirm no piston-to-valve interference after installation
• If dimensional mismatch is detected, halt installation and contact for cross-reference re-verification

Requesting a Fitment-Confirmed Quotation

Provide the engine serial number from the data plate, or the full machine model and approximate year of manufacture where the plate is unreadable. Photographs of the existing rocker arm assembly — particularly the pivot bore, adjuster end, and any casting numbers visible on the body — accelerate the identification process and allow cross-reference confirmation before an order is placed.

Frequently Asked Questions

Q: How do I confirm this rocker arm fits my specific engine serial number? A: Provide the engine serial number from the data plate. We cross-reference it against the documented build record to verify whether 3052170, 3052170rx, or 3047479 applies to your specific production run, including any running changes that affect valve train geometry.

Q: What is the difference between 3052170, 3052170rx, and 3047479 — are they fully interchangeable? A: 3047479 superseded 3052170 in later production, and 3052170rx designates remanufactured exchange units. They are not universally interchangeable across all engine serial ranges; verification against your specific engine build sheet is required before ordering.

Q: My machine only has a model number on a worn nameplate — can you still identify the right part? A: Yes. The machine model and approximate production year narrow the candidates significantly. We can dispatch a sample rocker arm assembly for physical trial fitment on your engine before you commit to a bulk order, eliminating guesswork.

Q: Can I order a sample to verify fitment before placing a bulk order? A: Yes, minimum order is one piece. Many repair centres standardising across mixed Cummins and John Deere fleets order a single sample to confirm pivot bore fit, adjuster geometry, and contact pattern before releasing a larger purchase.

Q: If the part doesn't fit despite matching the cross-reference, what happens? A: Contact us with photographs of the fitment issue and your engine serial number. We re-verify the cross-reference against the build record, identify the correct variant, and arrange resolution under the warranty terms covering manufacturing and identification accuracy.