Dimensional Grade Matched to Rebuild History — every STD connecting rod is verified against crankshaft journal condition and prior regrind records before dispatch.
Technical Specifications
| Parameter |
Value |
| Product Type |
Connecting Rod |
| Machine Fitment |
Komatsu 3D82, 3D82AE, Yanmar 3TN82E, 3TNV82A, 3TNE82 |
| Material |
Forged SAE 4340 alloy steel |
| Oversize Grade |
STD (additional grades 0.25 / 0.50 available) |
| Surface Treatment |
Shot-peened |
| Big-End Bore Roundness Tolerance |
±0.005 mm |
| Pin-to-Bore Clearance |
0.020–0.035 mm |
| Hardness |
HRC 38–42 |
| Tensile Strength |
≥1,200 MPa |
| Certification |
ISO 9001 |
| Warranty |
6-month standard warranty against manufacturing defects |
| MOQ |
1 piece |
Application Suitability
| Engine System |
Related Components |
| Rotating assembly (block internal) |
Con rod bearings, main bearings, piston assemblies |
| Lubrication system |
Oil pump, oil cooler, pressure relief valve |
| Cylinder combustion chamber |
Piston rings, cylinder liner, head gasket set |
| Engine overhaul kit matching |
Full gasket set, seal kit, thrust washers |
When a Connecting Rod Fails, the Damage Is Rarely Isolated
Replace the rotating assembly as a matched set — never just the broken rod.
In my time sourcing parts for fleets working across Indonesian mining sites, I have seen a single scored connecting rod destroy a freshly rebuilt crankshaft within hours. The root cause was rarely the rod itself. Oil starvation from a degraded pump, incorrect bearing clearance from a previous rebuild, or a mismatched oversize grade all produce the same catastrophic result. A STD connecting rod for Komatsu 3D82 Yanmar 3TN82E engine rebuild only performs correctly when the entire rotating assembly and the lubrication circuit that feeds it are verified together [NEED_CITE: diesel engine rotating assembly balance and bearing clearance standards].
The Rotating Assembly as a Balanced System
A connecting rod does not work alone. It sits between the piston and the crankshaft journal, transmitting combustion force while maintaining an oil film measured in thousandths of a millimetre. When one rod in a multi-cylinder engine is replaced without re-balancing the set, the mass difference introduces vibration that accelerates bearing wear across every cylinder. For the 3D82 and 3TN82E platforms, this means all rods, bearings, and pistons should be evaluated as a single rotating group during any overhaul.
Oversize Grade and Rebuild History Alignment
The crankshaft in your engine may no longer be at factory standard. Previous regrinds move the journal diameter into oversize territory, and installing a STD connecting rod on a reground crank produces excessive bearing clearance and rapid oil pressure loss. Before ordering, confirm the current journal measurement and any prior machining records. Engine serial variants across the Yanmar 3TNV82A and 3TNE82 range also carry different rod bolt specifications [NEED_CITE: crankshaft regrind grade identification for compact diesel engines].
Reading the Specifications That Actually Matter
Forged SAE 4340 alloy steel provides the tensile strength needed to survive repeated combustion loading without stretching. Shot-peening introduces compressive residual stress on the surface, which retards crack initiation at the big-end fillet — the most common fatigue failure point. The big-end bore roundness tolerance of ±0.005 mm ensures the bearing shell seats uniformly, maintaining hydrodynamic oil film across the full journal arc. Pin-to-bore clearance at 0.020–0.035 mm directly governs wrist pin lubrication; too tight and the pin seizes, too wide and impact loading fractures the small end.
The Cost of Skipping System-Level Verification
Ordering a connecting rod without confirming crankshaft condition or lubrication system health almost guarantees a return to the teardown bench. A mismatched oversize grade forces the entire engine apart again for correct bearings. An unresolved oil pump fault destroys the new assembly before the first oil change interval. These are not hypothetical risks — they are the dominant failure pattern in compact diesel rebuilds across Southeast Asian job sites [NEED_CITE: common causes of connecting rod bearing failure in rebuilt diesel engines].
Why Source This Part Through XUNPO
Own-production and qualified-sourced connecting rods carry identical QC and warranty terms under one account. Eight product categories mean your full overhaul list — rods, bearings, pistons, gasket sets, seal kits — ships as one consignment. Minimum order is one piece, so a single emergency replacement does not require a bulk commitment. Part identification works from engine serial number, nameplate photograph, or worn component image. Cross-reference verification covers superseded numbers across Komatsu 3D82 and Yanmar 3TN82E variants. Technical support confirms oversize grade and bearing compatibility before you commit to the order.
Documentation & Verification
- Commercial invoice listing oversize grade and engine compatibility reference
- Cross-reference sheet mapping STD connecting rod to interchange numbers (reference only)
- Dimensional inspection record covering bore roundness, hardness, and tensile compliance
- Six-month warranty terms covering manufacturing defects
- Packing photographs documenting rod condition before crate closure
- HS code and customs documentation support for international engine parts shipment
Installation & Rebuild Sequence
- Verify crankshaft journal diameter against STD grade before pressing in new bearing shells
- Clean all oil passages in the rod and block to remove machining residue and shot-peening media
- Torque rod bolts to engine manual specification in staged increments, checking big-end bore roundness after final torque
- Confirm pin-to-bore clearance with plastigauge before installing piston assembly
- Prime the lubrication system and verify oil pressure at idle before applying any load during initial run-in
Requesting a Matched Quote
Provide your engine model, serial number, and any known rebuild history so we can confirm the correct oversize grade and identify which companion components — bearings, piston assemblies, gasket sets — should ship alongside this STD connecting rod for Komatsu 3D82 Yanmar 3TN82E engine rebuild.
Frequently Asked Questions
Q: How do I know if I need STD or an oversize grade connecting rod?
A: Measure the crankshaft journal diameter or check the most recent rebuild record. A journal at factory specification takes STD. Any prior regrind moves you to 0.25 or 0.50 oversize bearings, and the connecting rod big-end bore must match. We confirm grade compatibility from your engine serial and machining history before dispatch.
Q: What other components should be replaced at the same time as the connecting rod?
A: Con rod bearings, main bearings, piston assemblies, and the full gasket set should be replaced as a matched group. The oil pump and pressure relief valve should also be inspected, since lubrication faults are the leading root cause of rod bearing failure. Consolidating these into one order prevents split shipments.
Q: Can the same connecting rod part number cover different engine serial variants?
A: The base rod casting may be shared across Komatsu 3D82, 3D82AE, and Yanmar 3TN82E variants, but rod bolt specifications, bearing shell thickness, and pin diameter can differ between serial ranges. We verify your exact engine serial against our cross-reference database (reference only) to confirm fitment before shipping.
Q: What system-level faults commonly cause connecting rod failure?
A: Oil pump degradation, blocked oil galleries, incorrect bearing clearance from a prior rebuild, and lubricant contamination all produce rod bearing failure that appears as a rod problem. Addressing only the damaged rod without correcting the lubrication circuit leads to repeat failure, often within the first service interval [NEED_CITE: root cause analysis methodology for diesel engine bearing failures].
