Product Overview

The VI8973286120 Crankshaft Gear is a precision-engineered timing component manufactured by ISUZU for the 4LE2 engine series. This gear mounts directly to the crankshaft and drives the camshaft via the idler gear, ensuring precise synchronization of the engine’s valve train and fuel injection system with piston movement.

The 4LE2 engine utilizes a gear-driven timing system—offering superior durability, longer service life, and more precise timing compared to belt or chain-driven alternatives. This robust design is ideally suited for the demanding, high-vibration operating conditions that excavators face daily.

Key Specifications

Compatibility

This genuine crankshaft gear is compatible with:

The engine serial number is located on the right side, upper front of the cylinder block. Please verify your equipment nameplate before purchasing to ensure accurate compatibility.

Function & Critical Importance

1. Timing Synchronization Core: Transmits rotational power from the crankshaft to the camshaft, ensuring intake and exhaust valves open and close at precisely the correct moments relative to piston position.

2. Precision Alignment Reference: Features timing marks that must align with corresponding marks on the idler gear and camshaft gear during installation.

3. Exceptional Durability: The gear-driven system eliminates timing belt stretching, wear, and tensioner failure issues, providing consistent and reliable timing throughout the engine’s service life.

4. Prevention of Catastrophic Damage: A worn or damaged crankshaft gear can cause timing drift, leading to power loss, increased fuel consumption, and potentially severe engine damage if valves collide with pistons.

Signs Your Crankshaft Gear Needs Replacement

• Engine running rough, misfiring, or vibrating excessively

• Noticeable power loss under load

• Unusual knocking or rattling noises from the timing case area

• Difficulty starting the engine

• Visible wear, chipped teeth, or cracks during inspection

Installation Notes

⚠️ Professional installation is strongly recommended for this genuine OEM component. Key considerations include:

• Timing mark alignment: The crankshaft gear timing mark must be precisely aligned with the idler gear mark before installation.

• TDC positioning: Ensure No. 1 cylinder is at Top Dead Center (TDC) on the compression stroke, with the front cover TDC mark aligned with the groove mark on the crankshaft pulley.

• Proper torque: All bolts must be tightened to manufacturer-specified torque values as listed in the service manual.

• Lubrication: Apply engine oil to the gear and bearing surfaces during installation.

• Backlash check: Verify proper gear lash using a 0.10 mm feeler gauge after installation.

Please refer to the Kobelco SK75-8 Parts Manual (S3LGC0002ZC15) or the ISUZU 4LE2 Engine Workshop Manual for complete installation procedures.

Why Choose Genuine OEM Parts?

FAQ

Q1: Is this a genuine OEM part or an aftermarket part?

A: This is a 100% Genuine ISUZU Original Part (part number VI8973286120). It is NOT an aftermarket or imitation product. Genuine parts are manufactured to ISUZU’s strict quality standards and are identical in every way to the parts used on the original production line.

Q2: How do I verify this part fits my machine?

A: Confirm your excavator model is Kobelco SK75-8 and the engine nameplate shows ISUZU 4LE2XCUA or AU-4LE2X. Applicable serial numbers for SK75-8: LG01-C0501–C9727 and LG01210001- and subsequent.

Q3: What is the difference between genuine parts and aftermarket “OEM-equivalent” parts?

A: Genuine OEM parts are manufactured under ISUZU’s direct quality control, using approved materials and processes. Aftermarket parts do not follow ISUZU’s strict specifications and may compromise engine performance, reliability, and safety. Suspiciously low-priced “alternatives” are often counterfeit and carry significant operational risks.

Q4: What other parts should I consider replacing at the same time?

A: When replacing the crankshaft gear, it is recommended to inspect and consider replacing:

• Idler gear and thrust washer

• Camshaft gear and vibration damper

• Front oil seal (crankshaft seal)

• Timing case gasket and O-rings

Q5: Does the 4LE2 engine use a timing belt or chain?

A: Neither. The ISUZU 4LE2 uses a gear-driven timing system—the crankshaft drives the camshaft directly through an idler gear, with no belts or chains involved. This design is more robust and reliable, especially for heavy-duty excavator applications.

Q6: Where is the engine serial number located on the 4LE2?

A: The 4LE2 engine serial number is located on the right side, upper front of the cylinder block. Always verify this number before ordering parts to ensure correct fitment.

Q7: What is the valve clearance specification for the 4LE2 engine?

A: Both intake and exhaust valve clearance (cold): 0.40 mm (0.0157 in) .

Q8: Can using non-genuine parts affect my warranty?

A: Yes. Using non-genuine parts may void your equipment warranty. ISUZU officially recommends using only genuine OEM parts to ensure engine performance, safety, and longevity.

Q9: What is the firing order of the 4LE2 engine?

A: The firing order is 1-3-4-2.

Q10: What is the gear lash specification?

A: A 0.10 mm (0.0039″) feeler gauge is used to verify proper gear lash between the crankshaft gear and idler gear during installation.