Cummins KTA38 Connecting Rods & Bearing Sets

Diesel Pro Power is your trusted source for high-quality connecting rods, bearing sets, bushings, and fasteners designed specifically for the Cummins KTA38 engine. Whether you're doing a top-to-bottom rebuild or replacing individual wear components, our catalog offers complete solutions backed by technical reliability and backed by over 40,000 satisfied customers worldwide.

Understanding the Role of the Connecting Rod in the KTA38 Engine

In the Cummins KTA38, the connecting rod serves as the vital link between the piston and the crankshaft, transferring the linear force from combustion into rotational motion. Each of the engine's 12 cylinders is paired with a dedicated forged steel connecting rod, and failure of even one rod or its bearing can lead to catastrophic engine damage. This makes the quality, size match, and material tolerance of each rod and bearing set absolutely critical for long-term engine health.

What Makes the KTA38 Rod Assembly Unique?

The KTA38 engine is designed for heavy-duty power applications including marine propulsion, mining, oil and gas, and large-scale industrial operations. The connecting rods used in this engine are:

• High-strength forged steel
  
  

• Balanced for vibration resistance
  
  

• Fitted with bushings and rod bolts engineered to endure continuous high-load performance
  
  

• Designed for compatibility with both standard and oversize bearings
  
  

Proper connecting rod function ensures optimal crankshaft rotation, smoother power transfer, and prevention of piston-to-wall interference.

Complete Catalog of KTA38 Connecting Rod Parts

We offer all major connecting rod-related components for the Cummins KTA38, including:

• Standard and oversized bearing sets (STD, 0.010", 0.020")
  
  

• Connecting rod bushings
  
  

• OEM-spec rod bolts
  
  

• Rebuild hardware kits for complete rod refurbishment
  
  

Bearing Sets for Cummins KTA38 Engines

Standard Bearing Set for KTA38 & KTA50

This standard-size connecting rod bearing set includes both upper and lower shells, enough to service one rod. Precision manufactured to Cummins factory tolerances, this set is designed for use in engines with no crankshaft journal wear or machining. Ideal for fresh rebuilds using a new or remanufactured crankshaft.

Features:

• Standard size (STD)
  
  

• Compatible with KTA38 and KTA50
  
  

• Ideal for new or unground crankshafts
  
  

• Sold per rod set
  
  

Oversize Bearing Set - 0.010"

If your KTA38 crankshaft journals have been ground down by 0.010", this set provides the required bearing thickness to restore factory-clearance specs. It includes both bearing halves for one rod.

Use Case:

• For engines with mild crank journal wear
  
  

• Common during in-frame overhauls
  
  

• Protects crankshaft from metal-on-metal contact
  
  

• Also fits KTA50 engines
  
  

Oversize Bearing Set - 0.020"

This is the next size up in the oversize category. It's ideal for engines where journals have been ground 0.020" undersize, whether due to scoring, pitting, or ovality.

Benefits:

• Allows reuse of crankshafts that have been twice-ground
  
  

• Supports long-term operation without clearance loss
  
  

• Helps reduce vibration and premature wear
  
  

Connecting Rod Bushings for Cummins KTA38

Each rod in the KTA38 engine requires a bushing at the small end (wrist pin end) to provide a low-friction, high-durability interface between the piston pin and rod. Our connecting rod bushings are compatible with the K19, K38, K50, and QSK19 engines, offering multi-model versatility.

Specifications:

• Made of high-load bronze alloy
  
  

• Designed for press-fit installation
  
  

• Sold individually (1 per rod)
  
  

• Designed for maximum oil retention and low galling risk
  
  

When to Replace a Rod Bushing

• Excessive piston pin side clearance
  
  

• Scoring or pitting inside the bushing
  
  

• Excessive oil leakage at the pin bore
  
  

• Clunking noises under load or startup
  
  

Replacing worn bushings ensures proper piston alignment and reduces wrist pin wear, maintaining the engine’s compression and combustion efficiency.

Connecting Rod Bolts for Cummins KTA38

Every KTA38 connecting rod is secured to the crankshaft with two heavy-duty rod bolts. These bolts are not designed for indefinite reuse. In fact, Cummins service literature recommends replacing them during every engine rebuild or rod bearing replacement.

Rod Bolt Features:

• Grade 12.9 tensile strength
  
  

• Designed for stretch torque methodology
  
  

• Sold per bolt (2 needed per rod)
  
  

• Threads treated to resist galling and seizing
  
  

Why You Should Always Replace Rod Bolts

Rod bolts experience extreme stress during each power stroke. Stretching, metal fatigue, and thread galling are common over time. A failed rod bolt can instantly destroy a cylinder block, crankshaft, and piston in seconds. New bolts are inexpensive insurance compared to the cost of a new block or crankshaft.

Technical Notes for Servicing KTA38 Connecting Rod Assemblies

Proper Installation Torque for Rod Bolts

Always refer to the current Cummins KTA38 service manual for torque specs. Torque-to-yield methods often apply, which means the bolt is tightened to a specified torque, followed by a rotational angle torque (e.g., 90 degrees). Using a calibrated torque wrench is mandatory.

Identifying Bearing Size Requirements

Before ordering rod bearings, micrometer measurements of the crankshaft journals must be taken. Using the wrong bearing size will result in either excessive oil clearance (leading to low oil pressure and rod knock) or too little clearance (causing seizure and bearing failure).

Common Journal Conditions That Require Oversize Bearings:

• Grooved or pitted journal surfaces
  
  

• Evidence of overheating
  
  

• Out-of-round or tapered journals
  
  

• Polishing or scoring from oil starvation
  
  

When to Rebuild or Replace KTA38 Connecting Rod Assemblies

A full rod replacement or rebuild is necessary when:

• The rod is bent due to hydro-lock or piston seizure
  
  

• Bushing bore is egg-shaped or cannot retain a press-fit bushing
  
  

• Rod cap shows evidence of elongation or improper seating
  
  

• Bolt threads are stripped or the bolt cannot reach proper stretch
  
  

Rebuild Checklist

1. Inspect rod for twist and bend using a precision jig
   
   

2. Check wrist pin bore alignment
   
   

3. Press out old bushing and clean bore thoroughly
   
   

4. Install new bushing and ream to proper ID
   
   

5. Install new rod bolts and verify bolt stretch during torque procedure
   
   

6. Fit new bearing shells (standard or oversize)
   
   

7. Check side clearance and oil hole alignment
   
   

Marine and Industrial Applications of the Cummins KTA38

The KTA38 is frequently used in:

• Offshore support vessels
  
  

• Tugboats
  
  

• Dredges and barges
  
  

• Large mining haul trucks
  
  

• Oilfield power generation
  
  

• Custom stationary equipment
  
  

In these high-demand environments, the integrity of each connecting rod and bearing set directly impacts uptime, fuel efficiency, and maintenance intervals.

Why Choose Diesel Pro Power for Your KTA38 Connecting Rod Components?

With more than 40,000 satisfied customers globally, Diesel Pro Power is the trusted supplier for commercial operators, fleet managers, and rebuild shops worldwide. Here’s what sets our products apart:

• OEM-grade compatibility: All parts meet or exceed Cummins specifications
  
  

• Immediate availability: In-stock items ship fast
  
  

• Bilingual support: We serve customers in both English and Spanish
  
  

• Technical expertise: Our team can assist with component compatibility, rebuild procedures, and spec verification
  
  

Tips for Long-Term KTA38 Engine Health

• Use high-quality engine oil and change it on schedule to extend rod bearing life
  
  

• Monitor oil pressure, especially under load
  
  

• Avoid overloading the engine—operating above rated horsepower accelerates bearing wear
  
  

• Listen for knocking noises during cold starts or under load, which may indicate bearing clearance issues
  
  

• Replace rod bolts and bearings during every major overhaul to prevent failures under load