Crankshaft For Cummins 4BT|3907803/3929036

Need a fast, cost-effective alternative to the original crankshaft 3907803 / 3929036? Our aftermarket Cummins 4BT crankshaft drops straight into any 4BT3.9 block-no machining, no surprises. From Komatsu PC200 diggers to John Deere 4045D tractors and 60–80 kW gensets, the shaft is forged from 40Cr in our own plant, heat-treated in-house, and ready to ship in as little as 72 hours. Same fit, same fatigue life, fraction of the OEM price.

(1)Built for Durability

We don't cast-we forge. Every 4BT crankshaft( 3929036) starts as 40Cr bar stock, hammer-forged on our 1,600-ton press for a denser grain flow than OEM sand-cast units. That extra toughness keeps turbocharged 4BT3.9 engines turning 3–5 years without the mid-life failures common in cheaper imports. Since we perform forging, machining, and balancing in-house at the same facility, you receive durability matching the original equipment crankshaft while avoiding additional costs and lengthy lead times.

(2)Precision Heat Treatment

Three‑stage treatment: Tempering → Induction Hardening → Stress-Relief Tempering

Achieves surface hardness of HRC 52–58 and a hardened layer depth of 3–5 mm

Delivers excellent wear resistance and core toughness

(3)Journal Accuracy & Balance

Journal surfaces precision-ground to Ra ≤ 0.4 μm and roundness ≤ 0.005 mm

Improves bearing life, reduces vibration, and lowers engine wear

Dynamic balancing ensures smoother operation in both mobile and stationary engines

(4)Quality Assurance

Over 30 inspection checkpoints, including ultrasonic flaw detection and hardness verification

Conforms to ISO9001 quality system standards

Optional third-party inspection reports available upon request

The CUMMINS 4BT crankshaft (3929036) is built to power 4BT3.9 engines across a range of industries:

Construction industry: Komatsu excavators PC200-5/PC220-5

Agriculture: John Deere tractors 4045D, Cummins PowerCommand 3.9G

Power generation: Cummins QSB3.3-G1 generator sets
 

For CUMMINS 4BT crankshaft (3929036) , we offer our customers a choice of different types of packaging boxes: plywood and crude wood.

Logistics: Global delivery with reinforced sea freight packaging

Important Technical Note

When installing a new crankshaft in a 4BT engine, always ensure compatibility with your engine block, bearings, and connecting rods. Forged steel crankshafts may require proper balancing during installation. We recommend inspecting all related components including main bearings, rod bearings, and the harmonic balancer to ensure optimal performance and longevity .

Why Choose Zhejiang Weilin?

· Specialized Expertise: We focus exclusively on forged steel crankshafts, bringing deep metallurgical knowledge and manufacturing precision to every product

· Factory-Spec Material: Our forged steel construction matches the original Cummins 4BT factory specification, providing superior durability over aftermarket cast alternatives

· Broad Compatibility: Single component supports multiple OEM part numbers (3907803, 3929036, 3908031, and more)

· Proven Performance: Designed to handle the 4BT's 105 hp stock output and 265 lb-ft torque, with ample reserve for increased power levels

· Direct Manufacturer Support: Competitive pricing and reliable supply chain directly from our facility

· Export Packaging: Coated in heavy anti-rust oil and packed in robust wooden crates (60x25x25 cm) to guarantee zero rust or transit damage

· Global Shipping: We support worldwide delivery for wholesale and bulk orders

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