Connecting Rod

Connecting Rods and Related Components for Cummins 6BTA Engines

The connecting rod system in a Cummins 6BTA 5.9 engine plays a critical role in the internal combustion cycle. Each connecting rod links a piston to the crankshaft, transferring the force of combustion into rotational motion that drives the engine. Whether you're performing a full rebuild or replacing a damaged rod, Diesel Pro Power offers a complete selection of high-quality connecting rods, bushings, bolts, and bearing sets for the 6BTA platform—engineered to meet OEM-level reliability.

Our inventory supports both fracture-split and non-fractured (also called machined cap) rod designs, with corresponding bearing sizes to match various rebuild tolerances. Let’s break down everything available in this section so you can confidently select the right parts for your Cummins 6BTA overhaul or repair.

Complete Connecting Rod Assemblies

Forged Connecting Rods for Cummins 6BTA Engines

The Cummins 6BTA engine is commonly equipped with forged steel connecting rods, designed for high-stress, high-RPM environments, often found in marine propulsion and heavy industrial settings. Our replacement rods are manufactured using precision forging and heat-treatment methods, ensuring durability under sustained load and temperature extremes.

We supply both major rod types used in B Series engines:

Fracture-Split Rods: These are modern rods that are deliberately fractured during manufacturing to ensure a perfectly matched cap and rod assembly. They must be used with matching fracture-specific rod bolts and bearing shells.
Non-Fracture Rods (Machined Cap): These older-style rods use traditional cap-and-rod machining. They’re compatible with earlier versions of the Cummins 6BTA engine and require standard rod bolts and bearings designed for this type.

Each connecting rod is balanced, inspected, and designed to meet Cummins factory specifications for length, bearing journal diameter, and weight. These rods are interchangeable with compatible models of the 6BTA and are commonly used across a wide range of 5.9L B Series industrial and marine applications.

Connecting Rod Bearings for Cummins 6BTA

Bearing sets are essential when servicing the connecting rod. Each connecting rod uses an upper and lower bearing shell to ensure smooth, friction-free motion on the crankshaft journal. Diesel Pro Power offers both standard-size and oversized rod bearings to accommodate various levels of crankshaft wear or journal regrind.

Non-Fracture Rod Bearings

These bearings are compatible with earlier Cummins 6BTA rods that use a traditional cap-and-rod machining design.

Standard Size Bearings – Ideal for crankshafts within original OEM specifications.
0.25 mm Oversize Bearings – Used when the crankshaft journal has been ground down by 0.25 mm during rebuild.
0.50 mm Oversize Bearings – Designed for journals ground down by 0.50 mm.

Each set services one connecting rod and includes both upper and lower bearing shells.

Fracture-Split Rod Bearings

These bearing sets are specifically engineered for use with fracture-split connecting rods found in newer 6BTA engines and compatible ISB/QSB variants.

Standard Size Fracture Bearings – Use these when crankshaft journals are within factory spec.
0.25 mm Oversize Bearings – Match these to journals reground by 0.25 mm.
0.50 mm Oversize Bearings – For journals with a 0.50 mm regrind.

Precision manufacturing ensures proper oil clearance and durability under continuous operation.

Connecting Rod Bushings for 6BTA Engines

Each connecting rod requires a piston pin bushing at the small end to ensure proper articulation between the piston and rod. Diesel Pro Power offers a high-quality connecting rod bushing for Cummins 6BTA engines, manufactured with high-tin bronze alloy for superior wear resistance.

Compatible with 4B, 4BT, 6B, 6BT, ISB, and QSB series engines.
Designed for interference fit and must be reamed to final specification after installation.
Critical for minimizing piston slap and maintaining pin-to-bushing clearance.

These bushings are essential when replacing pistons or servicing connecting rods to avoid future scoring or vibration.

Connecting Rod Cap Bolts for 6BTA Engines

Rod bolts secure the rod cap to the main connecting rod body and must withstand extreme stress during every power stroke. We provide two distinct types of rod bolts, depending on the connecting rod style:

Non-Fracture Rod Cap Bolts

Used with traditional two-piece rods.
Early style bolt, designed for reuse in lower-load applications but often replaced during rebuilds.
Engineered to handle OEM torque and tension specs for Cummins B series.

Fracture-Split Rod Cap Bolts

Must be used with fracture-style rods.
Precision torque-to-yield design—must always be replaced during rebuild.
Compatible with 6BT, ISB, and QSB engine variants.

Replacing rod bolts is a critical part of bottom-end service. Old bolts can stretch and lose clamping force, increasing the risk of rod bearing failure or catastrophic crankshaft damage.

Understanding the Difference Between Fracture and Non-Fracture Rods

When selecting connecting rod components, it’s important to determine whether your engine uses fracture-split rods or machined-cap (non-fractured) rods. Here’s how to distinguish the two:

Feature	Fracture-Split Rod	Non-Fracture Rod
Cap Joint	Irregular fracture surface	Smooth machined surface
Cap Bolts	Torque-to-yield (one-time use)	Standard reuse bolts
Bearing Design	Specific to fracture rods	Specific to non-fracture rods
Common in	Newer ISB/QSB variants	Older 6BTA models

Always inspect your existing connecting rods before ordering replacement bolts or bearings. Using incompatible components may lead to severe bottom-end failure.

Applications and Compatibility

The components in this section are designed to work with the Cummins 6BTA 5.9 engine, as well as compatible derivatives such as:

Cummins 6BT and 6B – Depending on year and rod style
Cummins ISB 5.9 and 6.7 – Certain components like bushings and bolts
Cummins QSB Series – Especially for fracture-split configurations
Marine and Industrial Engines – Common in gensets, propulsion systems, loaders, cranes, and drilling equipment

These parts are precision-engineered and field-tested to withstand the high thermal loads and mechanical stress typical of heavy-duty marine and industrial service.

Why Choose Diesel Pro Power for 6BTA Connecting Rod Parts?

With over 40,000 satisfied customers worldwide, Diesel Pro Power is trusted by marine engineers, fleet operators, and diesel mechanics who demand durability, accuracy, and immediate availability.

Ready-to-ship inventory – Most parts in stock and ship same day
Expert compatibility support – Help available to match CPL numbers and rod types
Global delivery – Serving customers in over 200 countries
Premium OEM-grade quality – Each part tested for fit and function

Whether you're tackling a full bottom-end rebuild or just replacing a worn bearing, our team ensures you get the right components, the first time.