Connecting Rod Catalog For Cummins Marine & Industrial Engines

Introduction: Why Connecting Rods Matter

The connecting rod is the unsung hero inside every Cummins diesel engine. Its job is to connect the piston to the crankshaft, converting the up-and-down motion of the piston into the rotary motion needed to drive power to the transmission, propeller, or generator. In both marine and industrial applications, Cummins connecting rods are subjected to extreme stress—operating under high loads and fluctuating RPMs. That’s why it's essential to use premium-quality connecting rods when rebuilding or repairing a Cummins engine.

At Diesel Pro Power, we offer high-quality aftermarket connecting rods that match or exceed OEM standards for strength, reliability, and performance. Whether you're working on a Cummins 6BTA, 6CTA, QSM11, KTA19, or another engine model, our parts are built for serious work—and serious uptime.

The Role of the Connecting Rod in a Cummins Engine

Core Functionality

Each connecting rod is forged to transfer thousands of pounds of combustion force per stroke. It must be durable enough to resist deformation and lightweight enough to avoid unnecessary stress on the crankshaft and pistons. Cummins rods are engineered to balance these demands in a range of environments—marine, industrial, trucking, agricultural, and generator systems.

Dynamic Forces at Work

In a typical Cummins engine, connecting rods are subjected to:

• Compressive and tensile forces every combustion cycle

• Inertial forces from rapid acceleration and deceleration

• Rotational forces from crankshaft motion

• Heat exposure from proximity to pistons and combustion chambers

Even minor wear can lead to catastrophic engine failure. That’s why regular inspection and timely replacement of worn or damaged rods is critical to maintaining your Cummins engine's longevity and performance.

Compatible Cummins Engine Models

At Diesel Pro, we carry connecting rods for a wide range of Cummins engine series. Below are some of the most requested models we support:

B Series

• Cummins 4BT / 6BT / 6BTA – Widely used in marine, industrial, and vehicle applications. Known for rugged simplicity.

• Common Applications: Marine fishing boats, small tugboats, gensets, off-road machinery.

C Series

• Cummins 6C / 6CT / 6CTA 8.3 – Larger displacement, found in commercial marine engines and larger machinery.

• Common Applications: High-horsepower marine vessels, heavy-duty construction equipment.

QSM Series

• Cummins QSM11 – An electronically controlled powerhouse in offshore, oilfield, and high-performance marine applications.

• Common Applications: Workboats, dredges, power generators, and commercial fishing vessels.

K Series

• Cummins KTA19 / KTA38 / KTA50 – High-horsepower engines used in major marine propulsion systems and mining.

• Common Applications: Tugs, barges, cargo ships, mining excavators.

ISX / QSX Series

• Cummins ISX / QSX15 – Found in larger land-based and power generation systems.

• Common Applications: Commercial trucks, gensets, oil & gas power units.

Don't see your model listed? Contact us—our inventory continues to grow, and we specialize in sourcing hard-to-find Cummins connecting rods for legacy and high-output engine models.

Why Choose Diesel Pro Connecting Rods?

At Diesel Pro Power, we don’t just sell parts—we provide trusted solutions. Here’s why customers around the globe rely on our connecting rods:

OEM Matching Specifications

Every connecting rod we sell is manufactured to meet or exceed original Cummins tolerances and design parameters, including:

• Bore diameter

• Rod length

• Center-to-center distances

• Cap screw torque specs

• Material strength and weight balance

Heat Treatment and Strength

Our rods are manufactured using forged steel and undergo advanced heat treatments for maximum fatigue resistance. They’re designed to last through countless cycles of high-load combustion.

Ready-to-Install

All rods are thoroughly inspected for dimensional accuracy. We offer both new and remanufactured options that arrive clean, measured, and ready for installation.

Affordable Aftermarket Pricing

You get Cummins-grade quality without Cummins-level pricing. We specialize in premium aftermarket components that offer the same performance at a better value—ideal for commercial operations where budget and uptime both matter.

Signs It’s Time to Replace Your Connecting Rods

Connecting rods may not give many warning signs before failure. If you're already rebuilding an engine or replacing pistons or crankshafts, it's the perfect time to inspect and possibly replace the connecting rods.

Look for these signs:

• Knocking or tapping noises from the engine block

• Loss of compression in one or more cylinders

• Visible cracks or fatigue marks on the rod or cap

• Rod bearing scoring

• Bent or twisted rods from hydro-lock or over-revving

• Piston slap or abnormal wear patterns

If any of these symptoms are present, it's essential to replace the rods before further damage spreads to crankshafts, pistons, or even the cylinder block.

Diesel Pro’s Replacement Guidelines

When to Replace

We recommend replacing your Cummins connecting rods when:

• Performing a full engine overhaul

• Bearings show signs of overheating or wear

• Engine has experienced a hydrolock event

• Cylinder walls or pistons show uneven wear

• The engine is being upgraded for higher output

Rod and Bearing Pairing

Always replace rod bearings along with your rods to ensure optimal clearances and oil film thickness. Diesel Pro also sells connecting rod bearing sets matched to Cummins specs.

Engine Applications: Marine, Industrial, Power Generation

Marine Applications

Saltwater, humidity, and long engine hours can degrade rods over time. Diesel Pro Power provides connecting rods for Cummins-powered:

• Charter boats

• Shrimp trawlers

• Tugboats

• Ferry systems

• Deep sea and reef fishing boats

• Workboats and offshore rigs

Industrial and Construction

Heavy-duty Cummins engines power excavators, drills, and compressors. In these applications, uptime is everything. Replacing worn rods as part of preventative maintenance can reduce catastrophic engine damage and extend the life of expensive equipment.

Power Generation and Gensets

From backup generators to primary power systems in remote locations, Cummins engines are trusted around the world. Replacing rods during scheduled maintenance ensures reliable performance when the power can't go out.

Technical Considerations When Replacing Cummins Connecting Rods

Torque Specs

Always refer to correct torque specs when installing connecting rods. Over- or under-torquing can lead to catastrophic engine failure. Diesel Pro provides installation resources and supports customers with technical expertise to ensure proper installation.

Reconditioning vs. Replacement

In some cases, rods can be reconditioned by resizing the big end bore or installing bushings. However, for critical applications or when any fatigue is visible, full replacement is the safer option.

Related Components Sold by Diesel Pro

A connecting rod doesn’t work alone. Consider replacing or inspecting these related Cummins components:

• Rod Bearings

• Pistons and Rings

• Wrist Pins

• Crankshafts

• Gaskets and Seals

• Main Bearings

• Cylinder Kits

• Engine Overhaul Kits

We also carry  new cylinder heads, lubrication pumps, and fuel injectors compatible with the same engine  Cummins marine and industrial engine models.

Why Diesel Pro is the Global Leader in Cummins Connecting Rods

We’ve built our reputation by making it easier—and faster—for engine professionals to find exactly what they need. With over 20 years of experience in the marine and industrial diesel industry, our mission is to deliver top-quality Cummins replacement parts that keep engines running and businesses moving.

Our Advantages

• Same-day shipping worldwide

• Bilingual support (English and Spanish)

• Easy part matching with engine model or CPL

• Trusted by marine fleets, diesel mechanics, and OEM rebuilders

• Thousands of 5-star customer reviews

Shop Connecting Rods by Cummins Engine Model

• Cummins 6B / 6BT / 6BTA

• Cummins 6C / 6CT / 6CTA 8.3

• Cummins QSB 6.7

• Cummins QSM11

• Cummins ISX / QSX15

• Cummins KTA19 / KTA38 / KTA50

Don’t see your model listed? Reach out—we’re constantly adding new inventory and may have exactly what you need.

Built For the World’s Hardest Working Engines

From shrimp boats in the Gulf to power plants in the Andes, Cummins engines operate in extreme environments. At Diesel Pro Power, our aftermarket connecting rods are built to match that same rugged dependability—ensuring your engine stays online, your equipment stays productive, and your business keeps moving.

Whether you're doing a full in-frame rebuild or just replacing a damaged rod, our parts give you Cummins-grade performance at a better price—with faster delivery and expert support.

Frequently Asked Questions About Connecting Rods (FAQ)

1. Are these rods compatible with marine and industrial Cummins engines?
Yes. All connecting rods offered by Diesel Pro Power are built to match both marine and industrial Cummins engine applications. Whether you're operating in saltwater conditions or heavy-duty inland construction, our rods are designed for maximum performance and durability.

2. Do you offer rods for the 6BTA marine engine?
Yes. We stock high-quality connecting rods for the Cummins 6BTA 5.9, including those specifically used in marine propulsion and auxiliary systems.

3. Can I reuse my old rod bearings?
Reusing rod bearings is not recommended. Bearings are precision-fit components that wear over time. Always replace them with new bearings when installing new rods.

4. Do you sell rod and bearing kits together?
Yes. We offer rod and bearing kits for many Cummins engine models, which ensures proper fit and reduces installation time. Contact us for availability specific to your engine.

5. How do your connecting rods compare to OEM parts?
Our connecting rods are engineered to match or exceed OEM performance specifications. They undergo strict quality control to ensure proper fit, balance, and durability—providing the same reliability as original Cummins parts at a more competitive price point.

6. Do I need to machine the connecting rods before installation?
No. Our connecting rods are ready to install. They are precision-machined and inspected to OEM specifications, requiring no additional machining.

7. Are oversized or undersized rods available?
We offer standard-sized rods designed to work with OEM crankshaft specifications. If your crankshaft journals have been machined undersize, we recommend using the appropriate undersized bearings instead.

8. Do your rods include bolts or fasteners?
Connecting rods are typically sold bare. However, rod bolt kits compatible with each engine model are available separately.

9. What torque should I use on the rod bolts?
Torque specs vary by engine model and bolt type. Always refer to the Cummins service manual for your specific engine or contact our support team for guidance.

10. How do I find my engine model?
To identify the correct connecting rod, you’ll need your Cummins engine’s serial number, which can usually be found on a dataplate located on the side of the engine block. If you're unsure where to look, visit our Help Center or send us a photo—our team is happy to assist.

11. How long does it take to ship?
We offer same-day shipping for in-stock items. Most orders placed before 3 PM EST ship the same business day from our Miami warehouse.

12. Do I need to check bearing clearances when installing a new connecting rod?
Yes. Even with brand-new rods and bearings, it’s critical to measure bearing clearances during assembly. Proper oil clearance ensures sufficient lubrication and prevents premature wear or engine failure.

13. Are your rods balanced?
Yes. Our connecting rods are manufactured and balanced to meet OEM weight specifications to ensure smooth engine operation and even power delivery.

14. Can I buy just one connecting rod?
Absolutely. You can purchase individual rods or full sets depending on your rebuild or replacement needs.

15. What is the return policy?
We accept returns on unused parts within 30 days of purchase. Visit our Returns Page for full policy details.

16. How do I know if my rod is bent?
Bent rods may cause piston misalignment or unusual engine noise. The most accurate method is inspection at a machine shop using rod alignment and bore gauges.

17. Will these rods fit automotive Cummins engines?
Many Cummins rods fit across marine, industrial, and automotive platforms. Confirm compatibility by serial number or contact us for assistance.

18. What if I don’t have the engine serial number?
The engine serial number is required to match the correct connecting rod. If you don’t have it, check your engine’s dataplate or contact your equipment manufacturer. Without the serial number, it is not possible to guarantee the correct fitment of the part.

19. Can I install these rods myself?
Yes, if you have engine assembly experience and the proper tools. Otherwise, we recommend installation by a professional diesel technician.

20. Do I need new wrist pins when replacing rods?
Wrist pins should be inspected for wear and scoring. We recommend replacing them during a rebuild for optimal piston-to-rod fit.

21. Do rods need to be replaced in pairs?
It’s not required, but replacing in pairs or full sets is ideal for balancing and ensuring even wear across all cylinders.

22. Do you ship internationally?
Yes. We ship worldwide with fast delivery and customs-friendly documentation to minimize delays.

23. Are these aftermarket or OEM rods?
Our rods are premium aftermarket parts—engineered to meet or exceed Cummins OEM specifications, offering exceptional value and performance.

24. Are rods for the 6CTA 8.3L in stock?
Yes. We offer connecting rods for all major CPLs of the Cummins 6CTA 8.3L engine, including both marine and industrial configurations.

25. Do your rods come pre-lubricated?
No. Connecting rods should be lubricated during installation with assembly lube or clean engine oil, per best practices.

26. Do you offer tech support?
Yes. Our technical team can help you select the right rod, verify fitment, and answer installation questions. Visit our Help Center or call us.

27. Are rods for KTA19 marine engines available?
Yes. We stock heavy-duty connecting rods for the Cummins KTA19, including marine-rated versions.

28. What’s the best way to inspect a rod for cracks?
Use non-destructive testing such as magnetic particle inspection (magnaflux) or dye penetrant testing for accurate results.

29. Do you stock connecting rods for genset engines?
Yes. We stock rods for Cummins engines commonly used in commercial and industrial generator applications.

30. Do I need to balance the engine after replacing rods?
If replacing with OEM-balanced rods, additional balancing is not required. However, verify all component weights during overhaul if performance is critical.

31. Can connecting rods be reused?
Only if the rod passes all visual, dimensional, and non-destructive inspections. In critical systems, replacement is the safer option.

32. Are connecting rods engine-specific or universal?
They are engine-specific. Always verify compatibility using your engine’s serial number.

33. What information do I need to order the correct connecting rod?

To ensure you receive the correct part, you’ll need your Cummins engine’s serial number. This number is typically stamped on a metal tag located on the engine block. Our team uses the serial number to match your engine to the exact connecting rod it requires. If you're unsure, send us a photo or visit our Help Center for assistance.