Premium S6D125 crankshaft (OEM 6151-31-1110) for Komatsu PC400-3 and PC400-5 excavators. Forged steel resists journal scuffing. Factory direct wholesale
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Heavy-duty forged alloy steel crankshaft for Komatsu S6D125, SA6D125, and SAA6D125E engines.
Induction hardened (HRC 52-58) journals prevent journal scuffing during high-stress mining operations.
OEM: 6151-31-1110 | Cross-reference: 6151-35-1010, 6252-31-1010, 6150-31-1020. Fits Komatsu PC400-5 excavators and WA470-3 wheel loaders.
Volume discounts available.
The Komatsu S6D125 and SA6D125 engine series represents a legendary 11.0L inline-6 heavy-duty diesel platform (11,045 cc) engineered specifically to drive heavy machinery, including Komatsu PC400-3, PC400-5, and PC410-5 excavators, WA470-3 wheel loaders, and D85E-21 bulldozers operating in grueling mining and quarrying environments. At the rotational center of this high-torque powerplant is the premium Komatsu S6D125 crankshaft (OEM 6151-31-1110, cross-reference 6151-35-1010, 6252-31-1010, 6150-31-1020), which converts linear piston forces into continuous driving torque. While lighter applications can utilize cast shafts, our S6D125 heavy shaft is precision-manufactured from high-tensile forged alloy steel to ensure maximum wear resistance under continuous torsional loads. To maintain peak combustion efficiency and prevent exhaust black smoke under severe earthmoving cycles, this core component of Komatsu S6D125 engine parts (OEM 6151-31-1110) relies on the high-performance induction hardened journal treatment. In severe, high-vibration heavy-duty shifts, common failure modes include bearing oil-film shear, causing journal scuffing discoloration damage or progressive main journal fatigue cracking along the journal fillet shoulders. To counter these stresses, each forged steel crankshaft S6D125 features induction-hardened main journals (110mm standard) and rod pins (80mm standard) finished with strict roundness limits. Rebuilders must check the crankshaft thrust play (standard: 0.050 to 0.220 mm) and verify the bearing oil clearance (standard: 0.050 to 0.096 mm) during any major 6151-31-1110 crankshaft replacement overhaul. This meticulous engineering makes it the ultimate WA470 crankshaft and Komatsu PC400 crankshaft replacement option, ensuring long-term rotation reliability for global mining fleets.
| Parameter | Value |
|---|---|
| Engine Code | Komatsu S6D125 / SA6D125 / SAA6D125E (11.045L) |
| Configuration | Inline-6 Cylinders, 24 Valves SOHC |
| Engine Cylinder Bore | 125.0 mm |
| Crankshaft Stroke | 150.00 mm (5.9055 in) |
| Main Journal Diameter | 110.00 mm (Standard Range: 110.000 – 110.015 mm) |
| Rod Pin Diameter | 80.00 mm (Standard Range: 80.000 – 80.015 mm) |
| Crankshaft Thrust Play | 0.050 – 0.220 mm (Wear Limit: 0.35 mm) |
| Crankshaft Net Weight | 102.00 kg (225 lbs) |
| Material Spec | Precision Forged Alloy Steel (42CrMo equivalent) |
| Hardness Treatment | Induction Hardened Journals (HRC 52-58) |
| Primary OEM Number | 6151-31-1110 |
| Interchange References | 6151-35-1010, 6252-31-1010, 6150-31-1020, 6151311110 |
Our Komatsu engine components catalog covers the full light-duty and heavy-duty inline families, from the 2.8L 4D94E and 3.3L S4D95 to the massive 11.0L SAA6D125 and 15.2L S6D155 lines. Explore our complete range of Komatsu diesel engine parts by visiting our Komatsu Brand Hub to find matching cylinder heads, cylinder liners, and camshaft assemblies.
| Engine Model | Primary Part Number | Machine Model |
|---|---|---|
| S4D95 | 6204-33-1100 | PC60-5 WA150 Loader |
| S4D102 | 6732-31-1100 | PC120-6 PC100-6 Excavator |
| S6D95 | 6207-31-1100 | PC200-5 PC200-6 Excavator |
| S6D102 | 6735-01-1310 | PC200-6 PC200-7 Excavator |
| S6D105 | 6136-31-1110 | PC200-3 Excavator |
| S6D107 | 6754-01-1310 | PC200-8 Excavator |
| S6D108 | 6222-31-1110 | PC300-6 Excavator |
| S6D110 | 6138-31-1110 | PC220-5 GD605 Grader |
| S6D114 | 6742-01-1570 | PC300-7 PC300-8 Excavator |
| S6D125 | 6151-31-1110 | PC400-3 PC400-5 Excavator |
| S6D140-2 | 6211-31-1010 | PC600-6 Excavator |
| S6D140-3 | 6217-31-1010 | PC750-6 PC800 Excavator |
| S6D140-5 | 6261-31-1200 | PC800-8 PC850-8 Excavator |
| S6D155 | 6127-31-1012 | D155A-2 Bulldozer |
| NT855 | 6710-31-1111 | D85 Bulldozer |
| NH220 | 6623-31-1111 | D60 Bulldozer |
| S6D170 | 6245-31-1100 | PC1250-7 Excavator |
| 4D95L | 6204-31-1201 | PC60 PC75 Excavator |
| 4D94E/4TNE94 | - | PC30 PC35 PC40 Excavator |
Komatsu crankshafts fit heavy machinery including Komatsu PC400-3 Excavator, Komatsu PC400-5 Excavator, Komatsu WA470 Wheel Loader, and Komatsu Bulldozers.
Contact us for complete application coverage.
| Make | Machine / Vehicle Model | Year Range | Engine Code | Crankshaft OEM |
|---|---|---|---|---|
| Komatsu | PC400-3 / PC400LC-3 Excavator (PC400-3 crankshaft) | 1985–1993 | SA6D125-1 | 6151-31-1110 |
| Komatsu | PC400-5 / PC400LC-5 Excavator (PC400-5 crankshaft) | 1991–1998 | S6D125-1 | 6151-31-1110 |
| Komatsu | WA470-1 / WA470-3 Wheel Loader (WA470 crankshaft) | 1987–1999 | S6D125-1 | 6151-31-1110 |
| Komatsu | D85E-21 / D85P-21 Bulldozer (forged steel crankshaft S6D125) | 1988–1996 | S6D125-1 | 6151-31-1110 |
Symptom: Metallic knocking sounds from the lower block, low engine oil pressure when warm, and rough idling during early startup. (journal scuffing discoloration)
Diagnosis: Oil contamination or low oil pressure degrades the lubricating film on the journal bearing. This causes direct metal-to-metal contact, leading to rapid journal bearing wear, excessive shaft play, and eventual housing contact.
Solution: Replace the crankshaft with a precision-balanced unit, use high-grade filters, and replace the engine oil pump and oil supply lines during overhaul.
Symptom: Hairline cracks on fillet radiuses, crankshaft snapping, or complete engine seizure under severe loading shifts. (S6D125 heavy shaft)
Diagnosis: Standard cast iron crankshafts have a random grain structure and lower tensile strength, making them susceptible to stress-fatigue cracking under high-torque digging cycles.
Solution: Sourcing an OEM-spec S6D125 heavy shaft (6151-31-1110) ensures a highly aligned grain structure with superior torsional and fatigue strength, safely enduring continuous high-idle excavator operations.
Symptom: Mismatched clearances, rapid bearing wear, or thrust washer binding shortly after initial engine startup. (6151-31-1110 crankshaft replacement)
Diagnosis: Incorrect torque sequence or improper bearing tolerances stretch main bolts unevenly, creating uneven oil clearances and leading to bearing failure.
Solution: Torque the main bearing cap bolts starting from the center cap outward in three progressive stages to the final specification of 245 Nm (180 ft-lb). Use Plastigage to confirm standard oil clearance (0.050 to 0.096 mm).
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