Engine Piston 8-97251696-1 / 8972516961 For ISUZU NPR NQR 4HE1 4HE1T 4HE1TC — Ø110 Mm STD, 66.2 Mm KH, Alfin + Oil Gallery, MOS2 Skirt

The Engine Piston with OEM references 8-97251696-1 / 8972516961 (and related forms 8-97251696-0 / 8972516960) is a verified replacement piston for ISUZU 4HE1, 4HE1T, and 4HE1TC diesel engines, used in NPR and NQR commercial truck applications. This piston converts combustion pressure into crankshaft rotation, and on the 4HE1 platform it is a standard (STD) Ø110 mm unit with a 66.2 mm compression height and a 40 × 87 mm full-floating piston pin.

The piston features an Alfin insert at the first compression ring land, an internal oil cooling gallery, and a MOS2 (molybdenum disulfide) coated skirt. These construction details are critical for the 4HE1's turbocharged and intercooled combustion cycle: the Alfin insert reinforces the top ring groove against thermal fatigue, the oil gallery manages crown temperature under sustained load, and the MOS2 coating reduces friction and scuffing during cold starts and initial break-in.

1. Ø 110 mm Standard Bore — This piston is Ø 110.00 mm (STD), designed for unworn standard cylinder liners. If cylinder bore wear exceeds OEM limits, an oversize piston (+0.50 mm or +1.00 mm) is required and the liner must be bored/honed accordingly. Confirm the original bore measurement before ordering.
2. Alfin + Oil Gallery + MOS2 Skirt — This is the reinforced turbo-diesel specification, not a basic naturally aspirated piston. The Alfin insert, oil cooling gallery, and MOS2 skirt coating are all confirmed features for this reference. Do not substitute a non-Alfin or non-gallery piston for turbocharged 4HE1T/4HE1TC applications.
3. Piston Rings and Liner Are Separate — This listing covers the piston only in standard supply. A piston kit with cylinder liner, rings, pin, and clips is available under the same reference family. Confirm the required scope (piston only vs. complete kit) at inquiry.

• ✓Bore Diameter Verified: Ø 110 mm (STD) — confirmed by product data ("직경 (mm) 110") and Gasgoo piston listings for the 4HE1 platform ("Dia.110 Mm").
• ✓Compression Height Verified: 66.2 mm — confirmed by Precision International ("Compression height 66.2mm") and multiple supplier listings ("Comp : 66.15", "66.2mm").
• ✓Piston Pin Verified: 40 × 87 mm — confirmed by technical data ("핀 (mm) 40*87").
• ✓Ring Groove Geometry Verified: 3.0HK (Half Keystone) top ring — confirmed by data ("반지 (mm) 3.0HK * 2.0*1.2*3.0") and Precision International ("3HK" in the ring specification).
• ✓Construction Features Verified: Alfin insert, oil gallery cooling, MOS2 coated skirt — confirmed by Precision International ("Includes alfin inserts on first compression ring, oil gallery cooling & MOS2 coated skirts") and ("Alfin, 오일 갤러리").
• ✓Engine Coverage Verified: 4HE1, 4HE1T, 4HE1TC — confirmed by FridayParts fitment data ("Fit For Isuzu Engine: 4HE1, 4HE1T, 4HE1TC").
• ✓Vehicle Coverage Verified: ISUZU NPR, NQR — confirmed by FridayParts ("Fit For Isuzu Truck: NPR, NQR").
• ✓Cross-Reference Density Verified: 8-97251696-1, 8-97251696-0, 8972516961, 8972516960 are consistently grouped as interchangeable/related references across FridayParts, Yishan, and other catalogs.
• ⚠Oversize and Kit Scope NOT Uniformly Specified: The standard supply format is piston only. A piston kit with cylinder liner, rings, pin, and clips is referenced under the same part number family by some suppliers. Confirm the exact package contents (piston only vs. complete kit) at inquiry.

• Loss of engine compression: Worn or stuck piston rings reduce cranking pressure, causing hard starting and noticeable power loss under load — particularly evident on 4HE1T/4HE1TC engines under boost.
• Excessive exhaust smoke (blue/white/black): Indicates oil passing rings or incomplete combustion — piston and ring replacement often resolves it when cylinder bores are within specification.
• Increased oil consumption: Glazed bores or tired ring packs allow oil into the combustion chamber, raising operating costs on fleet vehicles.
• Piston scoring or scuffing: Visible skirt wear or liner wall scoring caused by thermal expansion, insufficient lubrication, or turbo-related heat load — requires immediate replacement.
• Knocking or tapping noise: Piston slap from excessive skirt-to-bore clearance or a worn 40 mm pin bushing requires inspection before further engine operation.
• Ring land cracking: On high-hour or overheated 4HE1 engines, the original ring land can crack, leading to compression loss and potential piston break-up.

• Bore and compression height are the first checks: This piston is Ø 110 mm STD with 66.2 mm KH. Confirm the original piston's bore and compression height before ordering — a mismatched piston will not seal or may cause valve-to-piston interference.
• Alfin + Oil Gallery specification is critical for turbo engines: The 4HE1T and 4HE1TC are turbocharged/intercooled. The Alfin insert and oil gallery are not optional for these applications. Do not substitute a basic NA piston.
• Piston rings and liner are separate: Standard supply is the piston only. For a complete rebuild, order the piston ring set (reference TP 32677-STD per Precision International) and the cylinder liner kit separately, or specify the complete piston kit at inquiry.
• Oversize availability: For worn cylinder bores, +0.50 mm and +1.00 mm oversize pistons are typically available. Specify the required size at inquiry.

1. 1Confirm the original piston variant first: Measure the removed piston's bore (Ø110 mm), compression height (66.2 mm), and pin diameter (40 mm). Verify the presence of the Alfin insert and oil gallery — these are visible features.
2. 2Check cylinder liner wear: Measure liner bore for taper and out-of-roundness. If wear exceeds specification, replace the liner or bore/hone to the next oversize (+0.50 mm or +1.00 mm) and fit the corresponding oversize piston.
3. 3Verify ring end gap: Fit the new rings into the bore and check end gap against the workshop manual before assembly. The reference ring specification is TP 32677-STD (3HK / 2.5 / 4.0).
4. 4Install pin and circlips: Lubricate the 40 mm pin and bore, slide the pin through the piston and connecting rod small end, and seat new circlips fully.
5. 5Stagger ring gaps: Position ring end gaps at 120° intervals.
6. 6Lubricate and install: Coat the piston skirt and rings with clean engine oil; use a ring compressor for insertion.
7. 7Connecting rod torque: Follow the workshop manual specification and sequence for the 4HE1.
8. 8Weight matching: If replacing fewer than four pistons, verify weight compatibility with the existing assemblies to avoid imbalance.

• Use the correct diesel engine oil and adhere to ISUZU recommended intervals for the 4HE1. Degraded oil accelerates ring and skirt wear, especially on turbo engines.
• Check compression and oil consumption at every 50,000 km or if hard starting, smoke, or oil consumption develops.
• Maintain the cooling system and injection timing to protect piston crown and ring land integrity.
• Ensure air filter integrity — dust ingress is a leading cause of piston ring and skirt wear in commercial service.

• Standard packing: Neutral carton with protective wrapping; 4 pcs in one box (engine set); wooden pallet available for bulk export orders.
• Package contents (standard): 1 × Piston (with pin & circlips). Piston rings and cylinder liner are NOT included in standard supply — confirm at inquiry.
• Kit option: Piston kit with cylinder liner, rings, pin, and clips is available under the same reference family — specify "kit" at inquiry.
• Set options: Single piston / matched set of 4 for one 4HE1 engine / complete kit per cylinder — specify at inquiry.
• Suitable for: ISUZU NPR / NQR engine rebuilders, commercial truck fleet maintenance departments, diesel engine overhaul shops, spare parts distributors, and export wholesalers.