Product Description
CUMMINS 3802134 OEM MARINE STYLE PISTON KIT (.040 OVER) – 5.9L 12-VALVE (1989–1998)
The genuine CUMMINS 3802134 OEM Marine Style Piston Kit (.040 over) is the preferred choice for performance 5.9L 12-valve engine builds that demand higher thermal capacity, stronger crown design, and improved durability over standard automotive pistons. Originally engineered for high-load marine 6B applications, these pistons are known for their thicker crown, reinforced ring lands, and improved heat resistance—making them a proven upgrade for towing, competition, and high-boost 12-valve Cummins builds.
This kit offers factory-grade precision, perfect weight balance, and superior metallurgy only found in genuine Cummins piston assemblies. Whether you’re rebuilding a tired 12-valve or increasing cylinder pressure with larger injectors and turbo upgrades, the 3802134 Marine piston kit is one of the best OE-spec reliability upgrades you can install.
For a complete top-end refresh, pair this kit with Cummins connecting rod bearings, gaskets, and additional rotating assembly components available at CPP Diesel, such as the CUMMINS 3802070 OEM PISTON RING SET and CUMMINS 3901175 MAIN BEARING SET.
Key Features
- Genuine Cummins OEM Marine-style pistons – superior strength over standard automotive 12v pistons.
- .040" oversize for block overbore machining.
- Improved thermal load capability for towing and high-boost builds.
- Balanced OE design ensures proper engine smoothness and reduced vibration.
- Ideal for high-performance 12-valve Cummins builds (street, towing, competition).
Fitment Details
- Engine: 5.9L Cummins B-Series 12-valve (6B/6BT)
- Years: 1989–1998 automotive applications (verify ESN)
- Compatible Vehicles: Dodge Ram 2500/3500 5.9L 12-valve (1989–1998)
- Marine Origin: Piston design borrowed from high-strength 6B marine engines
Always confirm ESN/VIN for proper piston grade and oversize accuracy.
Cross-Reference & Related Cummins Components
- CUMMINS 3802070 OEM PISTON RING SET – 5.9L 12V
- CUMMINS 3901175 OEM MAIN BEARING SET – STANDARD
- CUMMINS 4955858 CONNECTING ROD BEARING SET – STANDARD
- VIEW ALL GENUINE CUMMINS PARTS
Cross-reference identifiers: 3802134, 3802134-040, 3802134RX (reman packaging), 3802151 (marine series family)
Installation Notes
- Block must be bored and honed to .040" oversize.
- Verify piston-to-wall clearance according to Cummins specification.
- Use only correct Cummins ring sets designed for this piston family.
- Ensure proper rod orientation and lubrication during assembly.
Specifications for cummins 3802134
| Attribute | Value |
|---|---|
| Brand | Cummins Genuine OEM |
| Cummins Part Number | 3802134 |
| Oversize | .040 Over |
| Application | 5.9L 12-valve Cummins (1989–1998) |
| GTIN | 607622024571 |
| UPC | 607622024571 |
| Cross Reference | 3802134RX, 3802134-040, 3802151 (marine series family) |
| E-Codes | Used in non-certified 6B/6BT applications; verify engine family for emissions compliance |
| Shipping Weight | Approx. 9–12 lbs depending on kit configuration |
| Shipping Method | Standard ground; heavy-duty packaging for piston protection |
| Prop 65 Warning | WARNING: This product may expose you to chemicals known to the State of California to cause cancer and reproductive harm. Visit https://www.P65Warnings.ca.gov. |
Frequently Asked Questions
ARE THESE REAL CUMMINS MARINE STYLE PISTONS?
Yes. This kit contains genuine Cummins OEM Marine-style pistons, which are stronger and more heat-resistant than standard automotive 12-valve pistons.
DO THESE PISTONS REQUIRE A .040" MACHINE BORE?
Yes. Your engine block must be bored and honed to match the .040" oversize specification.
WHAT RING SET DO I NEED FOR THESE PISTONS?
You will need the correct Cummins ring set, such as the CUMMINS 3802070 ring set, depending on your engine's ESN.
ARE THESE GOOD FOR HIGH-BOOST OR PERFORMANCE BUILDS?
Yes. Marine-style pistons are a common upgrade for street, towing, and competition 12-valve builds due to their thicker crowns and improved durability.
IS THIS KIT A FULL SET?
Yes. This listing is for a complete set of .040 over pistons. Pins and clips vary by Cummins packaging—contact us to confirm if your engine requires specific hardware.
