Cummins QSB 4.5 Parts - Crankshaft Section

Cummins QSB 4.5 Engine – Crankshaft & Related Components

The Cummins QSB 4.5 engine’s crankshaft assembly is one of the most vital elements of the powertrain, transforming linear piston movement into rotational force that drives your vessel or industrial equipment. To ensure optimal performance, it’s essential to maintain this system with high-quality bearings, seals, dampers, and gaskets designed specifically for QSB 4.5 engines.

At Diesel Pro Power, we supply a complete range of Diesel Pro aftermarket crankshaft parts for the Cummins QSB 4.5—trusted by over 40,000+ satisfied customers worldwide. Whether you’re doing a top-end refresh, a bottom-end rebuild, or preventative maintenance, we have the components you need, ready to ship.

Lower Gasket Set for Cummins QSB 4.5

The lower gasket set contains all the seals and gaskets required to service the bottom end of the QSB 4.5 engine. This includes crankcase seals, oil pan gaskets, and other sealing components essential to maintaining oil pressure and preventing leaks.

A fresh lower gasket set is critical when performing major crankshaft work—especially if you are replacing bearings or seals. Diesel Pro aftermarket gaskets are built to deliver long-lasting performance under heavy marine or industrial loads.

Crankshaft Bearing Shell Sets for Cummins QSB 4.5

Crankshaft bearing shells (also called main bearings) provide the low-friction interface between the crankshaft journals and the engine block. Over time, these bearings wear due to heat, load, and oil contamination, leading to reduced oil pressure and potential crankshaft damage.

We offer crankshaft shell sets in three size options for the QSB 4.5:

• Standard Size Bearings – Ideal for engines where the crankshaft journals are still within original factory specifications.

• Oversize 0.25 mm Bearings – Used when the crankshaft has been ground down 0.25 mm during a rebuild to restore surface finish and roundness.

• Oversize 0.50 mm Bearings – Designed for crankshafts that have undergone a more extensive grind to remove deeper scoring or wear.

Each bearing set includes both upper and lower halves for the complete engine, ensuring even wear distribution and smooth crank rotation. Our Diesel Pro aftermarket bearing sets are engineered for durability and precision fit.

Front Crankshaft Seal Kits for Cummins QSB 4.5

The front crankshaft seal prevents oil from leaking out of the front of the engine where the crankshaft exits the block to drive timing gears or belts.

We offer two main front seal kit configurations:

• Seal and Sleeve Kit – Includes both the sealing element and the metal sleeve to restore a proper sealing surface on worn crankshafts.

• Seal and Dust Shield Kit – Ideal for protecting the sealing lip from external debris, extending seal life in dusty or abrasive environments.

Diesel Pro aftermarket seal kits help maintain oil pressure and protect against contamination in marine and industrial conditions.

Rear Crankshaft Seal Kits for Cummins QSB 4.5

The rear crankshaft seal is critical for keeping oil contained at the back of the engine where the crankshaft connects to the flywheel.

We supply options for both dry clutch housing and wet clutch housing configurations:

• Dry Clutch Rear Seal Kit – Includes the sealing element and sleeve for engines with a standard dry flywheel housing.

• Wet Clutch Rear Seal Kit – Features a double-lip seal and sleeve, specifically designed for marine or industrial engines with a wet clutch setup to handle fluid exposure.

Installing a Diesel Pro aftermarket rear seal during clutch or transmission work helps prevent oil leaks that can damage clutch components.

Vibration Dampers for Cummins QSB 4.5

A vibration damper (also called a harmonic balancer) absorbs torsional vibrations from the crankshaft, reducing stress on the engine’s rotating assembly. Without a functioning damper, these vibrations can lead to premature crankshaft fatigue and bearing wear.

We offer two vibration damper sizes for the QSB 4.5 and related B-Series engines:

• 8.23” Outside Diameter – 4 Bolt Hole Design – Standard for certain QSB configurations and designed for optimal balance and fitment.

• 9.7” Outside Diameter – 4 Bolt Hole Design – Suitable for applications requiring a larger damper for improved vibration absorption under heavy loads.

Our Diesel Pro aftermarket dampers are precision-balanced to ensure smooth operation at all engine speeds.

Why Choose Diesel Pro Aftermarket Crankshaft Components?

The crankshaft is the heart of your QSB 4.5’s bottom end. Even minor wear in bearings, seals, or dampers can lead to oil leaks, vibration issues, and eventual catastrophic failure. Choosing Diesel Pro aftermarket parts ensures correct tolerances, proper oil clearances, and long-term reliability at a better value than OEM while meeting the same performance demands.

All of our QSB 4.5 crankshaft components are built for dependable service life in demanding marine and industrial environments.

Recommended Service Intervals & Installation Tips

• Bearings – Inspect at major service intervals or if low oil pressure or metal particles in the oil are detected.

• Seals – Replace whenever the crankshaft is removed or if oil seepage is visible.

• Vibration Dampers – Inspect every 1,000 hours for cracks, separation, or excessive wear; replace as needed.

• Gaskets – Always install new gaskets when components are removed to maintain sealing integrity.

For best results, use proper torque specifications and lubrication during installation, and always verify crankshaft end play after assembly.