Cummins Piston Ring Set 3802421 | 102mm Standard Rings for 4BT & 6BT Engines
Ensure optimal compression, oil control, and engine performance for your Cummins diesel engine with the Cummins Piston Ring Set 3802421. This precision-engineered ring set is specifically designed for the legendary Cummins B-series engine family—4BT 3.9L and 6BT 5.9L platforms—widely used in trucks, buses, construction equipment, and industrial applications worldwide.
3802421
Genuine Cummins Engine Parts Piston Ring Set 3802421
The 3802421 is a premium piston ring set manufactured to meet or exceed original equipment specifications. Designed for standard bore applications, this ring set delivers superior sealing, reduced blow-by, and extended engine life under demanding operating conditions .
| Specification | Detail |
|---|---|
| Part Number | 3802421 |
| Engine Compatibility | Cummins 4BT, 6BT, 4B, 6B series |
| Bore Size | 102mm (4.015 inches) |
| Ring Configuration | 3-ring set + oil ring |
| Ring Dimensions | 3T x 2.35 x 4mm |
| Applications | Trucks, buses, construction equipment |
| Quality | OEM-grade replacement |
Compatible Engine Platforms
The cummins engine parts piston ring set 3802421 is compatible with the following Cummins engine families:
| Engine Model | Displacement | Applications |
|---|---|---|
| 4BT 3.9L | 3.9L (239 cu in) | Step vans, forklifts, industrial equipment |
| 6BT 5.9L | 5.9L (359 cu in) | RAM trucks, buses, construction machinery |
| 4B 3.9L | 3.9L | Agricultural equipment, generator sets |
| 6B 5.9L | 5.9L | Marine, industrial, power generation |
These engines are widely used in:
- Heavy-Duty Trucks:Â Dodge RAM, medium-duty commercial trucks
- Buses:Â School buses, transit buses
- Construction:Â Excavators, loaders, backhoes
- Agricultural:Â Tractors, harvesters
- Industrial:Â Compressors, pumps, generator sets
Cross Reference Information
The Cummins 3802421 piston ring set cross-references with the following OEM and aftermarket numbers :
Why Choose Premium Piston Rings?
Piston rings are critical to engine health and performance. Quality rings like the 3802421 set deliver:
✅ Superior Compression: Maintains cylinder pressure for maximum power output
✅ Oil Control: Prevents oil consumption while ensuring proper lubrication
✅ Heat Transfer: Directs heat from the piston to the cylinder wall for cooling
✅ Reduced Blow-by: Minimizes combustion gas leakage into the crankcase
✅ Extended Engine Life: Reduces wear on cylinder walls and pistons
Technical Features
The Cummins piston ring set 3802421 is engineered with advanced features:
- Precision Fitment:Â Manufactured to exact OEM specifications for 102mm bores
- Durable Construction:Â High-grade cast iron material for wear resistance
- Proper Tension:Â Optimized radial pressure for consistent cylinder sealing
- Compatibility:Â Designed for both naturally aspirated and turbocharged applications
Applications & Use Cases
The 3802421 piston ring set is ideal for:
| Application | Specific Use |
|---|---|
| Engine Overhaul | Complete rebuild of 4BT or 6BT engines |
| Cylinder Kit Replacement | Paired with new liners and pistons |
| Oil Consumption Repair | Fixing excessive oil consumption issues |
| Compression Restoration | Restoring lost compression and power |
Complete Rebuild Solutions – Cummins Engine Parts for Sale
At Multistar Parts Co., Ltd., we offer comprehensive rebuild solutions for Cummins B-series engines:
Individual Components:
- Piston ring sets (3802421, 3802230, 3802746)
- Pistons and piston pins
- Cylinder liners and sleeve kits
- Connecting rods and bearings
Full Overhaul Kits:
- Inframe overhaul kits with gaskets
- Complete engine rebuild kits
- Gasket sets for 4BT and 6BT engines
Why Choose Multistar Parts Co., Ltd.?
As a specialized supplier of Cummins spare parts, we offer:
- ✅ Premium Quality: Genuine-grade components meeting OEM standards
- ✅ Extensive Inventory: Comprehensive stock of 3802421 and related parts
- ✅ Global Logistics: Worldwide shipping to minimize downtime
- ✅ Competitive Pricing: Wholesale rates for fleets, workshops, and distributors
- ✅ Technical Support: Expert assistance for parts identification
- ✅ Quality Assurance: Rigorous testing for durability and performance
Installation Tips for Piston Rings
When installing the 3802421 piston ring set on your Cummins 4BT or 6BT engine:
- Clean Ring Grooves Thoroughly:Â Remove all carbon deposits before installation
- Check Ring End Gap:Â Verify proper gap using feeler gauge in the cylinder bore
- Orient Gaps Properly: Stagger ring gaps 120° apart, not aligned with piston pin
- Lubricate During Assembly:Â Use clean engine oil on all rings and cylinder walls
- Use Proper Tools:Â Utilize piston ring expander pliers to prevent breakage
Keep Your Cummins B-Series Engine Running Strong
The Cummins 4BT and 6BT engines are renowned for their durability and longevity. Using quality piston ring set 3802421 ensures your engine delivers optimal compression, fuel efficiency, and reliable performance—whether on the highway, at the job site, or in continuous industrial operation.
Contact Multistar Parts Co., Ltd. today to order the Cummins 3802421 Piston Ring Set or inquire about our full range of Cummins spare parts. Whether you need a single ring set for a repair or wholesale quantities for engine rebuilding, we deliver the quality, reliability, and support your operations demand.
Trust Multistar Parts Co., Ltd. as your dedicated partner for genuine-quality Cummins engine components.
About Multistar Parts
Multistar Parts Cp.,Ltd is your reliable truck parts supplier for OEM truck parts and aftermarket truck parts solutions! We save your purchase time and give a best price!