Quick Answer: Piston 6684-91-3201 for Komatsu NH220 / NT855 / NTA855 Engines is a Piston for Komatsu machine and engine applications. It is identified by part number 6684-91-3201 and SKU KMP-6684-91-3201. The supplied application data lists N855-1, NH220-C1, NT855-1, NTA855-1, S6D155-4, S6D170-1, SA6D170-1, SA6D170-A-1T, VTA1710 as the related Komatsu engine information. Use the part number as the primary reference and confirm the exact engine build, machine model, and serial number before ordering.

Piston 6684-91-3201 for Komatsu NH220 / NT855 / NTA855 Engines ? Komatsu Product Overview

The Piston 6684-91-3201 for Komatsu NH220 / NT855 / NTA855 Engines is listed as a Piston for Komatsu equipment and engine service applications. The original catalog name for the item is PISTONS. For ordering and comparison, part number 6684-91-3201 and SKU KMP-6684-91-3201 should be treated as the primary product references rather than selecting the part by appearance alone.

What This Piston Does

This piston-related component operates inside the engine cylinder and works with the liner, rings, pin, and connecting rod. Piston crown design, dimensions, pin arrangement, and engine build can vary, making exact part-number matching important.

For engine repairs, use the engine identification and build information together with the part number. Internal engine and air-system components can change across production ranges even when the basic engine family remains the same.

Komatsu Engine Models and Machine Applications

The engine models below are the application references supplied with this product. They help narrow the correct Komatsu part, but an engine-family match alone should not be treated as guaranteed fitment. The same engine family can appear in more than one machine or production range, and component requirements can change by machine model, engine build, accessory arrangement, or serial number.

• N855-1
• NH220-C1
• NT855-1
• NTA855-1
• S6D155-4
• S6D170-1
• SA6D170-1
• SA6D170-A-1T
• VTA1710

Machine application note: The source file provides engine-model data but does not provide a complete machine-model list for every product. Specific Komatsu excavator, loader, dozer, haul-truck, or other machine models have therefore not been invented. Use the engine references above together with the actual machine model and serial number to confirm the application.

Product Details

• Product name: Piston 6684-91-3201 for Komatsu NH220 / NT855 / NTA855 Engines
• Part number: 6684-91-3201
• SKU: KMP-6684-91-3201
• Product type: Piston
• Application: Komatsu machines and engines
• Supplied engine data: N855-1, NH220-C1, NT855-1, NTA855-1, S6D155-4, S6D170-1, SA6D170-1, SA6D170-A-1T, VTA1710

Why Komatsu Part-Number Verification Matters

Part number 6684-91-3201 should be checked before purchase because Komatsu equipment can use different versions of the same general component across engine families, machine series, serial-number ranges, and production revisions. Parts can look nearly identical while differing in dimensions, connections, mounting, sealing profile, calibration, or internal construction. Matching only by a broad product description is therefore not enough for dependable identification.

Before Ordering This Komatsu Part

• Compare part number 6684-91-3201 with the existing component or a reliable parts reference.
• Confirm the complete Komatsu engine model, including suffixes and build designations when available.
• Confirm the Komatsu machine model and machine serial number.
• Check the component location, mounting arrangement, connections, dimensions, and surrounding assembly where relevant.
• For kits or major assemblies, verify the assembly or kit number as well as the individual component number.
• Do not use a product photo alone as final proof of fitment.

Information That Helps Confirm the Correct Komatsu Application

For a more accurate parts match, have the Komatsu machine model, engine model, machine or engine serial number, and original part number available. For hydraulic, turbocharger, electrical, or major engine components, assembly identification may also help distinguish between similar versions.

Application Note: References to Komatsu describe the machine or engine applications associated with this product data. Unless a specific listing expressly states otherwise, this wording does not represent a claim that the item is a genuine OEM Komatsu part.