STD Connecting Rod | Direct Fit for Komatsu 3D82 Yanmar 3TN82E

Verified Fitment — Dimensional checks on pin bore and big-end diameter confirm compatibility before dispatch.

Technical Specifications

Application Suitability

Why the Same Part Number Ships in Multiple Variants

A listed "compatible" STD Connecting Rod for Komatsu 3D82 / Yanmar 3TN82E fitment can still be wrong if the variant is not matched to your specific engine build.

Over the years I have opened boxes where the rod looked correct at first glance, but the pin bore diameter or big-end bolt spacing did not match the crankshaft and piston assembly already in the block. Superseded numbers get copied between cross-reference tables without variant notes, so a single base engine family can have several physically different rods sharing what appears to be the same reference. The cost of discovering this mismatch is not the part itself — it is the teardown, the idle machine, and the missed project deadline. [NEED_CITE: engine component variant tracking across production serial ranges]

Coverage Across the 82-Family Serial Range

This STD Connecting Rod for Komatsu 3D82 / Yanmar 3TN82E fitment spans five engine designations that share a common bore-and-stroke architecture. The Komatsu 3D82 and 3D82AE differ primarily in auxiliary drive layout, while the Yanmar 3TN82E, 3TNV82A, and 3TNE82 represent successive emissions and cooling system updates. The connecting rod envelope — center-to-center length, pin bore diameter, and big-end bore — remains consistent across these variants, provided no previous rebuild introduced oversize bearings or re-bored journals.

Pin Bore, Big-End Finish, and Bolt Pattern Checks

Before dispatch, three dimensions are verified against the target engine variant. The pin hole diameter is held to ±0.005 mm to ensure correct wrist pin float without excessive slap. The big-end bore surface is finished to Ra 0.4 μm so the bearing shell seats uniformly and oil film integrity is maintained under load. Bolt hole spacing and thread condition on the cap are also confirmed, because a rod from a different variant may bolt on but leave the cap misaligned by a fraction of a millimeter — enough to cause premature bearing wear. [NEED_CITE: connecting rod big-end bore surface finish and bearing shell seating requirements]

Reading the Forging and Surface Treatment

Forged SAE 4340 alloy steel gives the rod high tensile strength (1,200 MPa) and fatigue resistance under the repeated compression-tension cycles of a three-cylinder diesel. Shot peening introduces compressive residual stress on the surface, delaying crack initiation at the fillet radii where stress concentrates. The black oxide coating provides short-term corrosion protection during storage and initial run-in. Together these processes mean the rod can handle the peak cylinder pressures typical of turbocharged and naturally aspirated 82-family builds without dimensional drift over its service life.

What Happens When the Variant Is Wrong

A rod that bolts in but has even a slight dimensional mismatch does not fail immediately. The big-end bearing shell wears unevenly, oil pressure drops at operating temperature, and the knock that eventually appears is blamed on the crankshaft. In a rebuild environment this means a second teardown, new bearings, and possibly a reground crank — all because the initial STD Connecting Rod for Komatsu 3D82 / Yanmar 3TN82E fitment was matched to the base number rather than the serial-specific variant. The hidden cost is always the labor and machine downtime, never just the part. [NEED_CITE: root cause analysis of connecting rod bearing failures in compact diesel engines]

Why Source This Rod Through XUNPO

Our own production lines and qualified sourcing partners operate under a single warranty, so whether the rod ships from our Guangzhou facility or a certified forging partner, QC standards are identical. We stock common 82-family variants for quick dispatch and can machine or source less common builds on request. Minimum order is one piece — no MOQ barrier when a single machine is down. Every rod ships with a dimensional check record, and we can supply a sample for physical trial fitment before you commit to a bulk order for a fleet overhaul program. Our technical team verifies compatibility against machine model, engine serial number, or even a photograph of the nameplate when the original stamping is worn.

Documentation & Verification

• Commercial invoice and packing list referencing engine model and variant
• Part compatibility and cross-reference sheet marked for identification purposes only
• Dimensional inspection record covering pin bore, big-end bore, and cap bolt spacing
• Six-month warranty terms covering manufacturing defects
• Packing photographs showing individual anti-rust protection and rigid boxing
• HS code and customs documentation support for international shipment

Fitment Check Before Installation

• Compare pin hole diameter and big-end bore against the old rod before pressing the wrist pin
• Verify bolt pattern and cap alignment marks match the original forging orientation
• Check bearing shell crush height with new STD shells to confirm big-end bore is within spec
• Inspect bolt thread condition; replace fasteners if any stretch or thread deformation is visible
• Torque cap bolts to engine manual specification in two stages, then rotate crank by hand to confirm free movement

Request a Fitment Verification

Send the engine model, serial number, or a clear photograph of the nameplate and old rod stamping. We will cross-reference the variant, confirm the STD Connecting Rod for Komatsu 3D82 / Yanmar 3TN82E fitment, and provide a dimensional comparison sheet before you place an order.

Frequently Asked Questions

Q: How do I confirm this connecting rod fits my specific engine variant? A: Provide the engine model and serial number from the nameplate. We cross-reference the production serial range against our variant database, checking pin bore diameter, big-end bore, and bolt pattern. If the nameplate is unreadable, a photograph of the old rod — especially the big-end cap and forging marks — is usually enough to identify the correct variant.

Q: My old part number has been superseded — does this rod still match? A: Superseded numbers are common across the 82-family as manufacturers consolidate variants. We trace the supersession chain and verify whether the current replacement carries the same critical dimensions. If a dimensional change occurred at a specific serial break, we flag it before dispatch so there are no surprises during assembly.

Q: Why are there several rod variants for the same base engine model? A: Production changes over the engine's lifecycle — different turbo configurations, emission standards, or bearing material updates — can alter rod dimensions without changing the external engine model designation. That is why matching the serial range, not just the base model, is essential to avoid a fitment mismatch on the bench.

Q: Can I get a sample to verify fitment before placing a larger order? A: Yes. We supply a single piece for physical trial fitment so your rebuild team can confirm pin bore float, big-end bearing shell seating, and cap alignment on the actual engine block. Once fitment is confirmed, the bulk order ships against the same verified variant specification.