Rocker Arm Assembly 3052170 3047479 – Verified Fitment for Cummins NT855 N14

Verified Variant Matching — Cross-referencing 3052170, 3052170rx, and 3047479 against your engine serial range before shipping.

Technical Specifications

Application Suitability

Why the Same Part Number Ships in Multiple Variants

A single base number does not guarantee fitment across all engine serial ranges.

I have seen NT855 rocker arm assemblies ordered by the book arrive with oil passages that do not align with the cylinder head drilling. The part number matched the manual, but the engine had been built in a later production run where the oil feed routing was revised. [NEED_CITE: Cummins engine serial range variant documentation for NT855 and N14 platforms]. Superseded numbers like 3052170rx exist precisely because the original design was updated, yet many cross-reference tables still list them as interchangeable without noting the critical geometry differences. One wrong rocker arm assembly for Cummins NT855 N14 cross reference lookup can mean bent valves and a second teardown.

Mapping Serial Ranges to the Correct Rocker Arm Assembly

This rocker arm assembly covers a broad span of Cummins and John Deere engine families. The N14 and NT855 platforms share the same basic architecture, but production changes over the decades introduced subtle differences in pivot height, oil gallery drilling, and rocker shaft mounting patterns. Identifying the correct variant starts with the engine serial number and cylinder head casting mark, not just the machine model plate.

Interface Verification Beyond the Part Number

When the nameplate is worn or painted over, the machine model alone is not enough. The rocker arm must match the cylinder head casting in three critical areas: the pivot bore diameter, the oil feed hole position relative to the rocker shaft, and the valve bridge contact geometry. [NEED_CITE: cylinder head casting identification methods for heavy-duty diesel engines]. A rocker arm assembly for Cummins NT855 N14 cross reference check should include physical measurement of these interfaces, especially when the engine has been rebuilt previously and may have non-standard head work.

Dimensional Tolerances That Matter in the Valve Train

The pivot bore must maintain a precise interference fit with the rocker shaft to prevent oil pressure loss at the valve train. The valve contact tip radius affects load distribution across the valve bridge, and even slight deviation causes uneven wear on the crosshead. The oil feed hole alignment ensures pressurized lubrication reaches the pivot surface during operation. These dimensions are held to tight tolerances under ISO 9001 production control, and each batch is verified against the target engine specification before dispatch.

The Hidden Cost of a Mismatched Rocker Arm

Installing a rocker arm that appears to fit but has misaligned oil passages starves the pivot of lubrication, leading to premature shaft wear and eventual valve train failure. A rocker arm with incorrect pivot geometry alters valve lift and timing, reducing engine output and increasing fuel consumption. [NEED_CITE: valve train failure modes caused by incorrect rocker arm geometry in heavy-duty diesel engines]. The cost is not just the replacement part — it is the second teardown, the machine sitting idle, and the potential damage to valves, bridges, and the camshaft.

Why Buyers Source This Rocker Arm Assembly Here

Our own production lines and qualified sourced partners operate under one account with the same warranty terms, so whether the rocker arm assembly comes from our facility or a certified partner, the QC standard is identical. Eight product categories mean a complete valve train job — rocker arms, shafts, seals, gaskets — ships as one consignment. Minimum order is one piece, so a single emergency replacement is never blocked by volume requirements. Part identification works from a part number, machine model, photograph, or nameplate image. Cross-reference verification covers superseded numbers like 3052170rx and alternate references like 3047479. A sample unit is available for physical fitment confirmation before any bulk commitment.

Documentation & Verification

• Commercial invoice and packing list referencing engine model and serial range
• Cross-reference sheet mapping 3052170, 3052170rx, and 3047479 (reference only)
• Dimensional inspection record covering pivot bore, oil hole position, and tip radius
• Warranty terms covering manufacturing defects for 3–12 months
• Packing photographs showing part labeling and protective packaging before dispatch
• HS code and customs documentation support for international shipments

Fitment Check Before Installation

• Compare oil feed hole position on the new rocker arm against the removed unit
• Verify pivot bore diameter with a bore gauge before sliding onto the rocker shaft
• Check valve contact tip radius against the bridge surface for even load distribution
• Confirm mounting bolt pattern matches the cylinder head drilling pattern
• If any dimension does not match, stop installation and request cross-reference re-verification
• Photograph the installed unit before final assembly for warranty documentation

Requesting a Fitment Verification

Provide your engine model, serial number, and any readable part number from the old rocker arm. If the nameplate is gone, a photograph of the cylinder head casting mark and the removed rocker arm allows our technical team to confirm the correct variant. This rocker arm assembly for Cummins NT855 N14 cross reference service ensures you receive the exact build your engine requires before the package leaves our warehouse.

Frequently Asked Questions

Q: How do I confirm this rocker arm assembly fits my specific engine serial range? A: Provide your engine serial number and cylinder head casting mark. We cross-reference these against our fitment database covering NT855, N14, NH855, NTA855A, G855, and CM558 variants to confirm the correct oil passage alignment and pivot geometry for your specific build.

Q: My original part number differs from 3052170 — is 3047479 the correct replacement? A: Possibly. The numbers 3052170, 3052170rx, and 3047479 are cross-references that may apply to different production periods or engine variants. Send us your engine serial number and we will verify which reference maps to your exact cylinder head configuration and valve train specification.

Q: Why are there multiple part numbers for what looks like the same rocker arm? A: Cummins revised the rocker arm design across production years, changing oil gallery routing and pivot dimensions. Each number reflects a specific variant. Installing the wrong variant causes oil starvation or valve timing errors. We verify the correct number against your engine serial before shipping.

Q: I only have the machine model with no readable nameplate — can you still identify the right part? A: Yes. Send a photograph of the old rocker arm and the cylinder head casting mark. Our technical team uses these visual references along with the machine model to narrow down the engine variant and confirm the correct rocker arm assembly for your application.

Q: Can I order a single sample to verify fitment before placing a larger order? A: Yes. Minimum order is one piece. Order a sample, install it on one cylinder to confirm oil passage alignment, pivot fit, and valve contact pattern. Once fitment is verified, proceed with the full set for the remaining cylinders.