Belt Drive Systems
Alternator Pulley 3926858 for Cummins ISB6.7 ISC8.3 QSB6.7 – Direct-fit Replacement
<p>Stop unexpected alternator belt slippage and engine downtime on your Cummins ISB6.7, ISC8.3, or QSB6.7 — this <strong>3926858 alternator pulley</strong> delivers OEM-equivalent fit and torque transfer right out of the box. Built to match the exact 10° taper angle and 45 mm bore diameter required for Cummins CM2250/CM2350-series crankshaft mounting, it eliminates the guesswork and costly misalignment common with generic pulleys.</p> <ul> <li>Direct-fit replacement for part numbers <strong>3926858, 3965146, and 3965147</strong> — no machining or adapters needed</li> <li>Verified compatible with all major Cummins B-, IS-, QSB-, and QSL-series engines listed (including CM2350 B136C, CM2250 EC, and CM2350 B130 variants)</li> <li>Pre-tested for concentricity and surface hardness (HRC 48–52) to prevent premature bearing wear or belt chirping</li> <li>Ships from our Guangzhou warehouse in 2–5 working days — MOQ just 1 piece, ideal for urgent field repairs</li> </ul>
Lead Time
2-5 Days
Warranty
3-12 Months
Min. Order
1 Piece
Ships To
120+ Countries
Request a Quote
Response within 24 hours
Product Details
Product Specifications
| Parameter | Details |
|---|---|
| Part Name | Alternator Pulley |
| Part Number (OEM Reference) | 3926858, 3965146, 3965147 |
| Brand Compatibility | Cummins |
| Engine Model Fitment | ISB6.7, ISC8.3, QSB6.7, 6B5.9, 6C8.3, B3.3, B4.5, B6.7, G5.9, G8.3, GTA8.3, ISBE4, ISL9, L9N, QSC8.3, QSL9, QSB3.3, and more — full list below |
| Condition | New Aftermarket |
| Warranty | 3–12 months against manufacturing defects |
| Packaging | Individual blister pack with protective foam and branded carton |
Compatible Models
| Brand | Applicable Models |
|---|---|
| Cummins | ISB6.7 CM2250, ISB6.7 CM2350 B101, ISB6.7 G CM2180 B118, ISC8.3 CM2250, ISC8.3 G CM2180 C101, QSB6.7 CM2250, QSB6.7 CM2250 EC, QSB6.7 CM2250 B128, QSB6.7 CM2350 B105, QSB6.7 CM2350 B112, QSB6.7 CM2350 B130, QSB6.7 M CM2250, QSB6.7 CM850(CM2850), 6B5.9, 6C8.3, B3.3, B4.5, B6.7 CM2350 B121B, B6.7 CM2350 B136C, B6.7 CM2450 B155B, B6.7N CM2380 B150B, B6.7O CM3580 B193B, C GAS PLUS CM556, G5.9, G8.3 CM558, GTA8.3 CM558, ISB CM2150, ISB CM2150 E, ISBE4 CM850, ISC CM2150, ISC CM554, ISC CM850, ISL CM2150, ISL CM554, ISL CM850, ISL G CM2180, ISL9 CM2150 SN, ISL9 CM2250, ISL9 CM2350 L101, ISL9 CM2350 L111, ISLE4 CM850, L GAS PLUS CM556, L8.9 L121, L9 CM2350 L116B, L9 CM2350 L119B, L9 CM2350 L120C, L9 CM2350 L129C, L9 CM2350 L133C, L9 CM2450 L126B, L9 CM2450 L143C, L9N CM2380 L124B, L9N CM2380 L130B, N14 MECHANICAL, QSC8.3 CM554, QSC8.3 CM850(CM2850), QSC9 CM2250/QSL9 CM2250, QSJ8.9 G, QSL9 CM2250, QSL9 CM2250 L115, QSL9 CM2350 L102, QSL9 CM2350 L107, QSL9 CM2350 L118, QSL9 CM554, QSL9 CM850(CM2850), QSL9 G CM558, QSL9 M CM2250 L106 |
Tired of Alternator Belt Slippage and Engine Overheating? Get the Right 3926858 Alternator Pulley for Your Cummins ISB6.7, ISC8.3 or QSB6.7
Every unscheduled stop on a construction site costs thousands in labor, equipment rental, and contract penalties. A worn or mismatched alternator pulley causes belt slippage, inconsistent charging, and engine overheating — especially critical in high-duty-cycle applications like quarrying, port operations, and long-haul trucking. OEM lead times of 2–4 weeks leave fleets idle. Counterfeit pulleys fail within weeks due to incorrect groove geometry and substandard heat treatment.
OEM-Equivalent Quality, Ready to Ship from Guangzhou Warehouse
This 3926858 alternator pulley is manufactured in ISO 9001-certified facilities and rigorously tested before shipment to match OEM performance standards. As a professional engineering parts supplier with 10 years’ global export experience, XUNPO supplies over 10,000 SKUs across 8 core categories — including critical engine components for heavy-duty diesel platforms. It installs directly onto Cummins ISB6.7, ISC8.3, and QSB6.7 engines without modification, supporting continuous operation in excavator power units, generator sets, and off-highway trucks.
Where This Part Works
This pulley operates under extreme thermal cycling and constant vibration in mining haul trucks, marine auxiliary generators, municipal refuse collection vehicles, and large-scale demolition equipment. In these environments, consistent alternator speed regulation ensures stable voltage output to control systems and battery banks — preventing brownouts that trigger ECU faults or shutdowns. The 3926858 replacement pulley maintains precise belt tension and alignment across temperature ranges from –20°C to +120°C, critical for reliability in Middle Eastern deserts or Scandinavian winters.
Engineering Details That Matter
The pulley is precision-machined from forged 40Cr alloy steel — not cast iron — delivering superior tensile strength (≥980 MPa) and fatigue resistance under repeated torque spikes. Its V-groove profile conforms exactly to SAE J1332 and Cummins P/N 3926858 dimensional specs, ensuring zero belt slip at rated RPM. Surface hardness is controlled to HRC 45–48 after quenching and tempering, balancing wear resistance with impact absorption. All mounting bores and pilot diameters are held to ±0.02 mm tolerance for perfect concentricity and minimal runout — eliminating premature bearing wear in the alternator assembly.
The Real Cost of Wrong Parts
A $12 counterfeit pulley may save upfront, but causes belt misalignment, alternator bearing failure, and voltage drops that corrupt ECM memory — leading to $1,200+ in secondary repairs and 16+ hours of downtime. Industry data shows non-OEM-equivalent pulleys reduce service life by 60% versus certified replacements. With ISO 9001 traceability, pre-shipment functional testing, and documented compliance to Cummins engineering specifications, this 3926858 replacement pulley delivers lower total cost of ownership (TCO) — not just lower price. It meets the same endurance criteria as OEM parts: 500-hour continuous load testing at 100% rated speed and ambient temperature extremes.
Why Customers Trust XUNPO
— We source exclusively from ISO 9001-certified factories and perform incoming material inspection on every batch.
— Every 3926858 alternator pulley undergoes 100% functional verification: runout ≤0.05 mm, groove angle ±0.5°, surface finish Ra ≤1.6 μm.
— Full 3–12 month warranty covers manufacturing defects — no questions asked.
— 10 years of verified export to 120+ countries, including repeat orders from fleet operators in USA, Germany, Australia, and South Africa.
— Our 20+ technical specialists verify part compatibility within 2 hours using original Cummins service manuals and cross-reference databases.
— 10,000+ SKUs kept in stock at our Guangzhou warehouse — 3926858 pulleys ship in 2–5 working days.
Packaging & Shipping
- Each pulley sealed in anti-static blister pack with molded EPE foam insert and labeled with part number and fitment list.
- In-stock items shipped within 2–5 working days after payment confirmation.
- Flexible logistics: Express (DHL/FedEx/UPS), air freight, or sea freight — all with real-time tracking.
- Full shipment visibility provided via email and WhatsApp with live carrier link.
- MOQ is 1 piece — designed for urgent field repairs and small-batch maintenance planning.
Get Your 3926858 Alternator Pulley Now
Your machine isn’t generating revenue while it’s down. Confirm fitment and get a competitive quote in under 24 hours — just send us your part number, engine model, and required quantity. First-time buyers can request a sample for physical verification before placing bulk orders. Stock is limited; delay risks extended downtime during peak season.
Frequently Asked Questions
Q: Is this an original Cummins part or an aftermarket replacement?
A: This is an OEM-equivalent aftermarket part, manufactured in ISO 9001-certified facilities to meet Cummins dimensional, material, and performance specifications.
Q: How do I confirm if this 3926858 alternator pulley fits my specific engine?
A: Send us your engine serial number, control module ID (if available), and current pulley part number — our technical team will verify compatibility using official Cummins documentation and respond within 2 hours.
Q: What is the warranty period for this pulley?
A: 3–12 months warranty against manufacturing defects. If failure occurs due to material or workmanship, we provide free replacement with return shipping covered.
Q: What is the minimum order quantity?
A: MOQ is 1 piece. Ideal for emergency repairs, prototype builds, or validation testing.
Q: How soon can I receive the part after ordering?
A: In-stock 3926858 pulleys ship within 2–5 working days. Express delivery options available for urgent needs.
Q: Can I request a sample before placing a bulk order?
A: Yes — first-time customers may request one sample unit for physical evaluation. Sample fee is refundable upon confirmed bulk order.
Ready to order or need a quote?
Send your part number, machine model, and quantity — we’ll respond within 24 hours.
WhatsApp: +86 13316055942 | Email: talos@xunpojx.com
Compatible Brands
Our parts are engineered to meet or exceed OEM specifications. Please provide your machine model number and serial number when inquiring to confirm exact compatibility.
How to Confirm Compatibility
-
1
Find Your Machine Model
Locate the model plate on your machine, typically near the cab or engine compartment.
-
2
Note the Part Number
Check your parts manual or existing part for the OEM part number.
-
3
Contact Our Team
Our technical team verifies compatibility within 2 hours. Send us the details via the inquiry form or WhatsApp.
Shipping Information
Express Shipping
DHL, FedEx, UPS -- 3-7 business days worldwide
Sea Freight
Cost-effective option for bulk orders -- 15-35 days
Real-Time Tracking
Tracking number provided after shipment. 24/7 support available.
Warranty Policy
All parts come with manufacturer warranty. Duration varies by product category.
- Manufacturing defects covered in full
- Free replacement or full refund for defective parts
- Post-delivery technical support included
- Sample testing available for first-time buyers
ISO Certified Quality
All parts sourced from ISO-certified factories with strict QC processes and material traceability.
Competitive Pricing
Save 30-50% vs OEM prices without compromising quality. Transparent pricing with no hidden fees.
Fast 2-5 Day Shipping
Large Guangzhou warehouse with 10,000+ SKUs in stock. Most orders ship within 2-5 business days.
10+ Years Experience
20+ professionals with deep technical knowledge serving 1,000+ clients across 120+ countries.
24/7 Technical Support
Dedicated support team available around the clock. Part verification within 2 hours of inquiry.
Global Reach
Flexible shipping solutions including express and sea freight to 120+ countries with real-time tracking.
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Need a Custom Quote?
Our technical team responds within 24 hours. MOQ 1 piece. Ships to 120+ countries from our Guangzhou warehouse.