Catalog

HYUNDAI/KIA 3935023910 CRANKSHAFT

HYUNDAI/KIA 3935023910 CRANKSHAFT

Product Specifications

Product quality
OEM Equivalent Grade
starstarstar
Wholesale price USD $4.15
Wholesale price CNY ¥28.08
bolt MOQ (Minimal order)
50 pcs
local_shipping Production time
20-45 days
package_2 Shipping Weight: —
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HYUNDAI/KIA 3935023910
HYUNDAI/KIA 3935023700
HYUNDAI/KIA 3925023700
Overview & Operating Principle
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The CRANKSHAFT is the engine crankshaft — the primary rotating structural component of the reciprocating internal combustion engine that converts the linear reciprocating motion of the pistons and connecting rods into the continuous rotary torque delivered to the drivetrain. The crankshaft is a precision-forged or cast alloy steel shaft with a series of offset crank throws — each consisting of two crank arms and a crankpin journal — that are angularly phased at equal intervals around the shaft axis according to the cylinder count and firing order to produce evenly spaced power strokes and balanced rotating and reciprocating inertia forces. The crankshaft is supported in the engine block main bearing bores by precision-ground main journals running in replaceable plain shell bearings lubricated by pressurised oil from the main oil gallery; connecting rod big ends connect to the crankpin journals via a second set of plain shell bearings, also oil-pressure-lubricated through drillings from the main journals. Counterweights forged integrally with the crank arms offset the mass of the crank throws and the lower connecting rod to cancel primary and secondary rotational imbalance forces at operating speed, minimising vibration transmitted to the engine mounts and body. The crankshaft nose carries the timing sprocket or pulley, the crankshaft position sensor reluctor ring, and the vibration damper pulley; the flywheel end carries the flywheel flange and the pilot bearing bore for the transmission input shaft.

This unit — HYUNDAI/KIA 3935023910 — is manufactured to OEM-equivalent specifications: main journal and crankpin journal diameter and surface finish (Ra ≤0.4 μm), journal fillet radius geometry, main bearing bore centreline spacing, crank throw offset and angular phasing, oil drilling positions and diameters, reluctor ring tooth count and reference gap position, flywheel bolt flange bolt circle, front nose keyway and thread dimensions, and dynamic balance class are matched to the original part. Supplied individually as a complete crankshaft assembly. Available wholesale from 4.15 USD, MOQ 50 pcs, production lead time 20-45 days.

Crankshafts fail through main and crankpin journal bearing surface scoring and spalling from oil starvation — the most common failure mode, caused by inadequate oil pressure from a failed pump, blocked oil passages, or severely depleted oil level; through fatigue cracking at the high-stress fillet radius between the journal and the crank arm from detonation-induced overloads on turbocharged engines; and through torsional fatigue fracture of the shaft body from sustained operation with a failed vibration damper that allows torsional resonance to build to destructive amplitude. Journal surface damage that has progressed beyond the serviceable limit for grinding and fitting undersize bearings requires crankshaft replacement — a scored or cracked crankshaft cannot be reliably repaired to the surface finish and dimensional accuracy required for hydrodynamic bearing operation.

Symptoms & Diagnostics
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Deep knocking noise from the lower engine — heavy, rhythmic knock at crankshaft frequency that increases with engine load and is audible at idle — main bearing or connecting rod bearing failure from oil starvation or fatigue; main bearing knock is a lower-frequency thud heard best when the engine is under load; big-end bearing knock is a sharper higher-frequency knock most pronounced at idle when oil pressure is lowest; confirm by removing the spark plug of the suspected cylinder and rotating the engine — the knock reduces when that cylinder's combustion load is removed.
Oil pressure warning light at idle — confirmed low oil pressure at idle from gauge reading or scan tool live data with oil level correct and oil pump confirmed serviceable — main bearing clearances have increased from journal wear beyond the limit that the oil pump can maintain pressure against; the bearing clearances have become large enough that the pump flow rate cannot build adequate gallery pressure; this condition causes rapid secondary damage to camshaft and valve train components from reduced oil pressure throughout the engine.
Metallic particles — large shiny flakes or bearing shell fragments — visible in the oil at drain or collected on the magnetic sump drain plug — bearing shell material is breaking away from the steel backing under the load of insufficient oil film; inspect the drained oil in a white container under good light; bearing shell fragments require immediate engine shutdown and investigation before any further running that extends the damage.
Crankshaft position sensor fault codes P0335–P0339 combined with confirmed sensor and wiring serviceability — the CKP reluctor ring on the crankshaft nose has been damaged by contact with a failed front seal or timing cover component; or the crankshaft has shifted axially from a failed thrust bearing, moving the reluctor ring out of the sensor's read window; measure crankshaft end float against the OEM specification when a CKP fault cannot be explained by sensor or wiring faults.
Visible oil leak at both the front crankshaft seal and the rear main seal simultaneously — seals confirmed new and correctly installed — excessive crankshaft runout from worn main bearings is causing the shaft to oscillate eccentrically against both seals, wearing the seal lip contact zones faster than normal; new seals against a crank with excessive runout will fail within a short interval; measure main bearing clearances with Plastigage to confirm wear before ordering replacement seals again.
Engine vibration at a specific RPM range that deteriorates progressively over weeks — felt through the steering wheel, floor, and body at all speeds above idle — the crankshaft vibration damper has failed, allowing torsional resonance to build in the crankshaft at its natural frequency; sustained operation in resonance fatigues the crankshaft at the high-stress fillet radii and will eventually cause torsional cracking; inspect the damper rubber isolator immediately if this symptom is reported.
Logistics & Customs
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International HS Code
8483.10
EAEU Customs Code (TN VED)
8483 10 220 0
Typical Net Weight
Country of Manufacture
China
Standard MOQ
50 pcs
Production Lead Time
20-45 days
Always verify the exact 8-digit or 10-digit subheading with your customs broker for the destination country, as tariff schedules and duty rates vary by jurisdiction.
Installation Tips
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  1. Measure all engine block main bearing bore diameters before installing the new crankshaft — a block with worn or out-of-round main bearing bores cannot provide the correct housing bore diameter for the new bearing shells; each bore must be within the OEM tolerance at two perpendicular orientations; bores outside tolerance require line boring before the new crankshaft is installed; never install a new crankshaft into a block with unmeasured or out-of-tolerance bearing bores.
  2. Measure the new crankshaft's main and crankpin journal diameters and surface finish before installation — confirm each journal diameter is within the OEM standard or specified undersize tolerance; inspect the surface finish at 90-degree intervals around each journal under magnification for any machining marks, pitting, or handling damage; a journal with surface irregularities below Ra 0.4 μm will destroy the new bearing shells within a short operating period.
  3. Verify bearing clearances with Plastigage on all main journals before final assembly — place a strip of Plastigage across each journal, torque the main bearing cap to specification, remove the cap, and measure the crushed Plastigage width against the reference card; the clearance on each journal must fall within the OEM specification — typically 0.020–0.060 mm; clearances outside this range require bearing shell selection by grade or journal regrinding; never assemble the engine with unmeasured bearing clearances.
  4. Lubricate all bearing shells, journal surfaces, and thrust washers with fresh engine oil or assembly lube immediately before installation — the crankshaft's journals are in boundary lubrication for the first seconds of operation before the oil pressure circuit fills; a dry bearing surface during the first crankshaft revolution produces immediate scoring that destroys the new journal surface; coat every bearing surface generously with clean engine oil of the correct specification before the crankshaft is lowered into the block.
  5. Torque all main bearing cap bolts in the OEM sequence and in the specified number of passes — main bearing caps on modern engines use torque-to-yield stretch bolts that must be replaced at every assembly; the torque sequence — typically from centre caps outward — and the multi-pass tightening procedure are critical for correct bearing bore geometry; a cap tightened out of sequence or in a single pass distorts the bore and produces bearing shell fretting from the first revolution.
  6. Install the new CRANKSHAFT (HYUNDAI/KIA 3935023910), complete all engine assembly with new gaskets, seals, and oil filter, prime the oil circuit by cranking without the ignition system enabled until oil pressure is confirmed on a gauge, start the engine and hold at 2,000 RPM for 5 minutes while monitoring oil pressure continuously, then perform the OEM specified run-in procedure before subjecting the engine to full load; do not exceed 3,000 RPM or apply full throttle during the first 500 km of operation.
Tools: internal micrometer for bore measurement, external micrometer for journal diameter, Plastigage for bearing clearance verification, dial gauge for crankshaft runout and end float, torque wrench with angle gauge for stretch bolts, engine assembly lube, oil pressure gauge for initial startup monitoring.
Frequently Asked Questions
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When should a crankshaft be replaced rather than reground to accept undersize bearing shells?
Crankshaft replacement is required rather than regrinding in four situations: when journal surface damage — scoring, spalling, or pitting — extends below the maximum permissible undersize dimension; when fatigue cracks are visible at any journal fillet radius, regardless of crack depth — any crack in a crankshaft is a replacement criterion with no exceptions; when the crank has been operated with a failed vibration damper and shows torsional fatigue damage at the high-stress fillet radii; and when the original journal diameter has already been reground to the maximum available undersize and a further grinding would exceed the minimum acceptable wall thickness. Regrinding is appropriate when journal wear is within the undersize range, the fillet radii and oil drillings are undamaged, and the crank body shows no cracks on Magnaflux or dye penetrant inspection. ok.parts supplies crankshafts at wholesale MOQ from 4.15 USD per unit.
What oil change interval is required to protect crankshaft bearing life, and what are the consequences of extension?
The OEM oil change interval is the maximum permissible interval under normal operating conditions — it is not a conservative recommendation that can be safely extended. Engine oil's anti-wear additive package — ZDDP and similar extreme-pressure additives — depletes progressively from the first kilometre of operation; by the end of the OEM interval the additive package has been substantially consumed. Extending the interval beyond OEM specification allows the oil to operate without adequate anti-wear protection, permitting metal-to-metal contact at the hydrodynamic bearing interfaces during cold start before the oil film is established and during sustained high-load operation when film thickness is marginal. The cumulative damage from repeated overextended intervals is invisible until bearing clearances have grown sufficiently to produce low oil pressure — at which point the crankshaft and connecting rods have already sustained significant bearing surface damage that progressively accelerates.
How does the OEM-equivalent aftermarket unit compare to the genuine OEM part?
OEM-equivalent units in this catalogue replicate the current OEM design geometry and material specification. Quality is verified against OEM cross-reference data. When ordering in bulk, confirm with our team that the specification matches the latest OEM revision for your application.
Is white-label or custom packaging available for wholesale orders?
Yes. ok.parts works directly with the manufacturing facility and can accommodate neutral white-label packaging or fully branded packaging with your company logo, part numbers, and barcode. Minimum order quantities and lead times for custom packaging may differ from standard stock. Contact the team via the inquiry form to discuss your specific requirements.
Frequently Replaced Together
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PartReason for Combined Replacement
Main and Connecting Rod Bearing Shell Set
Standard or undersize — matched to journal diameter		New bearing shells must always be fitted with a new or reground crankshaft — reusing old shells against a new crankshaft immediately introduces the old shell's worn surface profile and embedded abrasive particles to the new journal surface. Select shells by grade to achieve the OEM clearance specification confirmed by Plastigage measurement; shells of the correct grade installed to the measured clearance are the most critical single factor in crankshaft and bearing longevity.
Engine Oil Pump
OEM ref. varies by engine		Crankshaft bearing failure caused by inadequate oil pressure from a worn or failed oil pump must be addressed simultaneously with the crankshaft — fitting a new crankshaft with the same failed pump reproduces the oil starvation condition from the first startup. With the engine fully disassembled for crankshaft replacement, the oil pump is fully accessible; always test the old pump's pressure output against the OEM specification and replace it if it is below specification or if its service life is unknown.
Engine Rebuild Gasket Set
Complete set including head gasket, seals, and O-rings		Crankshaft replacement requires complete engine disassembly, during which every gasket and seal in the engine is disturbed; all must be renewed at reassembly — reusing any gasket or seal from a disassembled engine produces a leak at that joint within a short operating period from the permanent compression set that the old gasket or seal has taken. A complete engine gasket set ensures every sealing interface is renewed simultaneously in a single assembly operation.