Overhaul Rebuild Kit 5-87813-954-0 For Isuzu 4HG1 4HG1T 4.6L NPR NPR300

Overhaul Rebuild Kit 5-87813-954-0 for Isuzu 4HG1 4HG1T 4.6L NPR NPR300

1. Quick Notice

Confirm your engine code (4HG1, 4HG1T, 4HF1) and NPR chassis model before ordering. This is a complete overhaul rebuild kit containing pistons, liners, bearings, valves, and full gasket set. Professional engine machine shop installation required. Follow Isuzu workshop manual for torque specifications and assembly sequence.

2. Description

 The 5-87813-954-0 is a complete engine overhaul rebuild kit for Isuzu 4HG1 4.6L inline-four diesel engines, including naturally aspirated (4HG1) and turbocharged (4HG1T) variants. The 4HG1 engine features 105mm bore, 125mm stroke, 4,570 cc displacement, and 17.5:1 compression ratio. Power output ranges from 135–145 hp. This comprehensive master rebuild kit includes overhaul gasket set (cylinder head gasket, valve cover gasket, intake/exhaust manifold gaskets, oil pan gasket, front/rear main seals, valve stem seals), four cylinder liners, four pistons (std), four piston pins, eight snap rings, four rod bushings, four piston ring sets (std), main bearing set (std), rod bearing set (std), thrust bearing set, four intake valves, four exhaust valves, eight valve guides, four intake valve seats, and four exhaust valve seats. Applications include Isuzu NPR250, NPR300 (1998–2003), NKR, ELF trucks, plus excavators, wheel loaders, bulldozers, and agricultural equipment powered by 4HG1/4HG1T engines. Common rebuild indicators include excessive oil consumption, blue exhaust smoke, loss of compression, cylinder knocking, low oil pressure, high crankcase blow-by, and metal debris in oil.

3. Parameters Table

4. Custom Content

Component Quality: All major hard parts are manufactured to meet or exceed OE specifications. Pistons and liners are cast to factory tolerances. Bearings and gaskets are sourced from tier-one diesel engine component manufacturers.

Machine Shop Requirements: This master kit requires professional installation by a certified engine machine shop. The cylinder block must be properly cleaned, inspected for cracks, line-bored, decked as necessary, and honed to correct cross-hatch pattern with proper piston-to-bore clearance before final assembly.

Valve and Guide Installation: Valve guides and seats require precision machining using valve seat cutting tools or grinding stones to achieve correct valve seat width (approximately 1.5mm), runout within 0.03mm, and proper valve recession depth relative to cylinder head face. Final valve lapping is required after seat cutting to ensure gas-tight seal.

Gasket Sealant Application: Apply liquid gasket (silicone RTV) at two locations where the engine front cover meets the cylinder head during reassembly. Do not apply sealant directly to cylinder head gasket surfaces — MLS gaskets seal dry.

Pre-Installation Checks: After assembly, prime the lubrication system by cranking with fuel disabled until oil pressure registers on gauge. Perform compression test to verify all cylinders are within 10% of each other before first start.

Break-In Procedure: For the first 50 operating hours, avoid sustained heavy loads, vary engine speed, and perform oil and filter change after initial break-in period.

5. FAQ

Q1: What is included in the 5-87813-954-0 rebuild kit?
A1: Full gasket set, four pistons (std), four cylinder liners, four ring sets (std), main/rod/thrust bearings, four intake valves, four exhaust valves, eight valve guides, four intake seats, four exhaust seats, piston pins, rod bushings, and snap rings.

Q2: Which Isuzu trucks use the 4HG1 engine?
A2: Isuzu NPR250, NPR300 (1998–2003), NKR, and ELF trucks. Non-US/Canada NPR300 models.

Q3: Is this kit suitable for turbocharged 4HG1T engines?
A3: Yes. Compatible with both naturally aspirated 4HG1 and turbocharged 4HG1T variants.

Q4: What engine specifications does the 4HG1 have?
A4: 4.6L inline-four diesel, 105mm bore, 125mm stroke, 17.5:1 compression ratio, 135–145 hp.

Q5: What are common engine failure symptoms requiring rebuild?
A5: Excessive oil consumption, blue exhaust smoke, loss of compression, cylinder knocking, low oil pressure, high crankcase blow-by, and metal debris in oil after oil change.

Q6: Does this kit require special installation tools?
A6: Yes — cylinder liner puller/installer, ridge reamer, valve guide driver, valve seat cutting tools, ring compressor, torque angle gauge, and dial indicator for piston protrusion measurement.