Connecting Rod 719810-23100 – Cross-Reference for Yanmar 3TNE78

Verified Variant Fitment — big-end bore and pin concentricity checked against the specific Yanmar 3TNE78 serial range before dispatch.

Technical Specifications

Application Suitability

Why the Same Base Number Ships Across Several Engine Builds

A matching part number does not guarantee the bore tolerance or cap alignment fits your specific serial range.

Superseded reference numbers and variant differences across engine generations are the reason a connecting rod for Yanmar 3TNE78 can arrive looking correct yet fail during assembly. I have stood in humid workshops in Southeast Asia watching mechanics force a rod into place because the big-end bore was fractionally out of tolerance for that engine build. The dowel-pin pattern matched, but the bearing shell clearance did not, and the engine seized within the first operational shift [NEED_CITE: connecting rod bearing clearance tolerances for small-bore diesel engines]. When nameplates are rusted flat or painted over, relying on a machine model alone invites exactly this kind of field failure.

Serial Range Coverage and Variant Mapping

This connecting rod for Yanmar 3TNE78 and its Komatsu-platform equivalents covers a wide spread of serial breakpoints. The Komatsu PC27R-8, for instance, appears across serial prefixes F30001, F31103, and F32154 — each potentially tied to a different internal engine configuration. The same base identifier, cross-reference 719810-23100, also maps to Komatsu 3D75N, 3D78AE, 3D78N, 3D80, 3D82AE, and 3D82E series engines. These platforms share a family resemblance but differ in crank journal diameter and rod bolt specification. Confirming the exact serial prefix before dispatch prevents the situation where a rod bolts on but runs with incorrect bearing crush.

Interface and Alignment Verification

The dowel-pin rod cap alignment on this component is a critical fitment checkpoint. Earlier or alternate designs sometimes rely on bolt-only cap location, which leaves room for lateral shift during field reassembly. Dowel pins hold the cap in exact register with the rod body, meaning the big-end bore stays round after the cap bolts are torqued. When you receive the part, compare the dowel position and pin bore diameter against the old rod or the engine service manual specification [NEED_CITE: dowel-pin versus bolt-only connecting rod cap alignment methods]. A mismatch in pin spacing is immediately visible and tells you the variant is wrong before any assembly begins.

What the Forged Steel and Surface Treatment Mean in Service

SAE 1045 forged steel, heat-treated, provides the tensile strength needed for the cyclic loading in a three-cylinder diesel operating at high torque output. Forging aligns the grain structure along the rod beam, which matters far more than a simple material grade label suggests. The phosphate coating with oil sealant is not cosmetic — it prevents micro-corrosion during storage and provides initial lubrication on the bearing shell interface during the first seconds of engine start-up. Together, these specifications mean the connecting rod cross reference 719810-23100 arrives ready for assembly without additional surface preparation, provided it has been stored properly after delivery.

The Hidden Cost of a Near-Miss Fitment

A connecting rod that bolts into place but carries the wrong big-end bore tolerance will not fail immediately. It will run for days, sometimes weeks, before the bearing shell begins to overheat and the crank journal scores. By then the crankshaft may need regrinding, and the repair bill extends well beyond a single rod replacement. In remote job sites, a crankshaft regrind is not a same-day option — the machine sits idle while parts and machining capability are sourced. This is the cost of accepting a cross-reference number at face value without verifying the serial-range fitment or requesting a dimensional check report [NEED_CITE: crankshaft journal scoring caused by connecting rod bore tolerance mismatch].

Why Buyers Source This Rod Through Our Verification Process

Our own production lines and qualified sourced supply operate under a single warranty, so you do not juggle separate claims if a batch spans both sources. We stock eight equipment component categories under one account, which matters when a full engine rebuild requires seals, gaskets, and bearings alongside this rod. Single-piece orders ship without minimum-quantity barriers, supporting emergency single-cylinder repairs. Identification is possible from a part number, a machine model, a photograph of a worn nameplate, or a physical measurement set. Cross-reference verification covers superseded and alternate numbers like YM719810-23100 and 71981023100 so discontinued references still resolve to a current supply. Samples ship for physical fitment confirmation before any bulk commitment, which is the safeguard I always recommend when the engine serial range sits near a production breakpoint.

Documentation & Verification

• Commercial invoice and packing list referencing the exact serial range confirmed for each rod.
• Part compatibility and cross-reference sheet listing 719810-23100 and alternate numbers as reference only.
• Quality inspection record showing big-end bore diameter and pin bore concentricity measurements.
• Six-month warranty terms covering manufacturing defects, clearly stated per unit.
• Packing photographs documenting anti-rust film and individual rigid box condition before crate closure.
• HS code and customs documentation support tailored to destination-country import requirements.

Fitment Check Before Installation

• Measure the big-end bore with the cap torqued to spec and compare against the engine manual tolerance.
• Verify dowel-pin spacing matches the old rod before pressing in the new bushing.
• Check pin bore diameter and surface finish; any scoring indicates transit damage.
• Confirm rod bolt thread condition and stretch length against service limits.
• If the serial range sits at a breakpoint, request our cross-reference verification sheet before assembly.

Confirm Your Machine Fitment

Send us the machine model, serial number prefix, and a photograph of the old rod or engine nameplate. We will cross-check against the known variant breakpoints and return a fitment confirmation or flag the specific measurement that needs physical verification. For mixed fleets running both Yanmar and Komatsu platforms, provide the full engine list so we can map which machines share this rod and which require a different variant.

Frequently Asked Questions

Q: How do I confirm this connecting rod fits my exact machine serial range? A: Provide the machine model and the serial number prefix from the chassis plate. We cross-check against documented serial breakpoints for Komatsu PC20R-8, PC27R-8, PC27MR-2, and PC27MR-3, as well as Yanmar 3TNE78 variants, and return a fitment confirmation with the specific engine build referenced.

Q: My old part number is different — is 719810-23100 still the correct replacement? A: Part numbers are superseded across engine generations. Send the old number and we will verify whether it resolves to cross-reference 719810-23100, YM719810-23100, or a different current identifier. Some superseded numbers map to the same rod; others indicate a variant change that affects bore tolerance.

Q: Why does the same base number appear with a YM prefix and without it? A: The YM prefix designates a Yanmar-origin numbering convention. Both 719810-23100 and YM719810-23100 can refer to the same connecting rod, but not always. We verify each reference against the engine serial range to confirm whether the YM-prefixed version is interchangeable for your specific build.

Q: I only have the machine model and no readable part number — can you identify the right rod? A: Yes. The machine model combined with the serial number prefix narrows the engine build variant. Where the serial range straddles a production change, we request a photograph or a big-end bore measurement from the old rod to resolve any remaining ambiguity before shipping.

Q: Can I order a single sample to verify fitment before buying a full engine set? A: Single-piece orders ship without minimum-quantity requirements. Buyers rebuilding multiple engines typically order one connecting rod for Yanmar 3TNE78 first, confirm physical fitment on the bench, and then release the bulk order for the remaining cylinders with confirmed variant accuracy.