Intake Valve 8-97131729-2 for ISUZU 4JG2 4JH1 with 42mm Head Diameter and 118mm Total Length, OEM Interchangeable Engine Inlet Valve

The Intake Valve 8-97131729-2 (8971317292) is a direct-fit OEM replacement for ISUZU 4JG2 and 4JH1 diesel engines, commonly installed in NHR, NKR, and TFR/TFS applications. This intake valve opens during the intake stroke to admit air into the combustion chamber. Worn or burnt intake valves cause compression loss, rough idle, and reduced power.

The intake valve is driven by the camshaft and rocker assembly. When the cam lobe lifts the valve, air (or the air-fuel mixture in indirect injection engines) enters the cylinder. When closed, the valve face seals against the valve seat to maintain compression during the compression and power strokes. The valve stem slides in the guide, and wear in either component leads to leakage, oil consumption, or valve noise.

• Confirmed Dimensional data: Valve head outer diameter 42 mm, total length 118 mm — recorded from aftermarket supplier data for this OEM family.
• Confirmed Net weight: 0.12 kg per valve — consistent across multiple independent supplier listings.
• Confirmed OEM cross-reference: Replaces 8-97131729-2 / 8971317292. Interchangeable references include 8-97131729-0 / 8971317290, 8-97131729-1 / 8971317291, and 8-97080214-1 / 8970802141.
• Verify 4JG1 fitment unconfirmed: Available search data links this specific OEM number primarily to 4JG2 and 4JH1. The related number 8941332751 is listed for 4JG1, 4JG2, and 4JB1. If your engine is a 4JG1, verify the original valve number before ordering.
• Partial Material data: Supplier listings indicate Cr40 for intake valves in this family, with claimed wear and corrosion resistance. No independent hardness or fatigue test data was found.

• Burnt or eroded valve face (visible pitting or material loss at the sealing edge)
• Valve stem wear causing excessive guide clearance and oil consumption
• Loss of compression, misfire, or rough idle
• Backfiring through the intake manifold
• Visible cracks at the valve head-to-stem transition area

1. Remove the cylinder head; disassemble the valve train and remove the old valves.
2. Clean and inspect the valve guides; replace if wear exceeds the OEM limit.
3. Inspect and recondition the valve seats to the correct angle.
4. Install the new valve; check stem-to-guide clearance.
5. Valve clearance (cold): Confirm the exact value in the workshop manual for your specific engine model. ISUZU 4J-series specifications vary by engine code — do not assume a single value across 4JG1, 4JG2, and 4JH1.
6. Adjust clearance at TDC on the compression stroke per the manual sequence.
7. Reassemble and perform a compression/leak-down test before startup.

• Check valve clearance every 20,000–30,000 km or per the OEM service interval.
• Inspect valves during any cylinder head service. Replace if burnt, cracked, or if stem wear exceeds the limit.