Cummins QSC Engine Parts – Crankshaft Section

The Cummins QSC engine is a mid-range diesel powerhouse designed for reliability, durability, and performance across both industrial and marine applications. At the heart of the QSC lies the crankshaft assembly—the rotating backbone of the engine that converts piston movement into usable power. Because of the stresses involved in high-torque diesel engines, the crankshaft and its related components—bearings, seals, dampers, and gaskets—are essential to maintain for proper engine function.

At Diesel Pro Power, we stock a complete selection of Cummins QSC crankshafts and related components. With more than 40,000 satisfied customers worldwide, we’ve built our reputation on fast shipping, expert support, and the highest-quality replacement parts for Cummins engines.

The Role of the Crankshaft in Cummins QSC Engines

The crankshaft is one of the most critical moving parts inside the Cummins QSC. Built from forged steel and precision-machined for exact tolerances, the crankshaft:

• Converts reciprocating piston motion into rotational force.

• Balances engine loads to reduce vibration.

• Works with main bearings and rod bearings to provide smooth operation.

• Connects to the vibration damper and flywheel for balanced power transfer.

Without a properly functioning crankshaft, the QSC engine cannot deliver the torque and reliability that operators expect. Over time, heavy loads, poor lubrication, or operating conditions can cause wear on the crankshaft surfaces, bearings, or associated seals. That’s why having access to new crankshaft assemblies and high-quality service components is vital for engine longevity.

Crankshaft Assemblies for Cummins QSC Engines

Diesel Pro Power supplies brand-new Cummins crankshaft assemblies designed to meet or exceed original OEM specifications. These assemblies are built for QSC and compatible engines such as the 6C, 6CT, 6CTA 8.3, and ISC series, ensuring coverage across multiple Cummins platforms.

Features of Our Cummins QSC Crankshaft Assemblies

• Forged steel construction for strength and durability.

• Precision balancing to minimize vibration and maximize efficiency.

• Direct replacement fit for straightforward installation.

• Compatibility with CM850 and HPCR (High Pressure Common Rail) fuel system engines.

By choosing a new crankshaft instead of a reground or remanufactured one, operators benefit from extended service life and reduced risk of premature wear.

Gasket Sets for Cummins QSC Engines

When replacing a crankshaft or performing bottom-end work, gasket sets are an essential companion. Diesel Pro Power provides upper and lower gasket sets for Cummins QSC engines, ensuring proper sealing during reassembly.

Upper Gasket Sets

Upper gasket sets are typically used for cylinder head service and include seals for intake, exhaust, and valve components. For the QSC engine, upper sets are available for both EGR-equipped engines and non-EGR applications with CM850 and HPCR systems.

Lower Gasket Sets

The lower gasket set focuses on crankshaft-related components, sealing areas like the oil pan and gear housing. A complete lower set ensures oil containment and prevents leaks that could damage the crankshaft bearings.

Crankshaft Bearing Shell Sets

Bearings are one of the most critical service items in the crankshaft assembly. They support the crankshaft inside the block, ensuring smooth rotation under extreme load. Diesel Pro Power offers standard and oversize crankshaft bearing shell sets for Cummins QSC engines.

Standard Size Bearings

• Designed for engines where the crankshaft journals are still within original specifications.

• Upper and lower shells included for complete coverage.

• Provide the factory fit and oil clearance needed for long service life.

Oversize Bearings

• Offered in increments such as 0.25 mm and 0.50 mm for engines where the crankshaft journals have been machined or worn.

• Allow continued use of the crankshaft after refinishing.

• Maintain proper oil film thickness to prevent metal-to-metal contact.

Using the correct size bearings is essential to avoid low oil pressure, premature wear, or catastrophic crankshaft failure.

Crankshaft Seal Kits

Oil seals protect the crankshaft at both the front and rear housings, preventing oil from leaking out of the engine while allowing the shaft to rotate freely. Over time, seals can harden, crack, or wear down, especially in high-heat or high-load environments.

Front Crankshaft Seal Kits

• Designed for Cummins QSC and related engines including the 6C and ISC.

• Include both the seal and protective sleeve for a complete solution.

• Available for automotive and non-automotive applications.

Rear Crankshaft Seal Kits

• Seal the crankshaft where it exits toward the flywheel and clutch housing.

• Offered for both dry clutch and wet clutch housing applications.

• Available in single-lip and double-lip designs depending on operating conditions.

Regular replacement of seals helps prevent oil loss and protects bearings from contamination.

Vibration Dampers for Cummins QSC Engines

The vibration damper (also called a harmonic balancer) is mounted to the crankshaft to absorb torsional vibrations. These vibrations are caused by the crankshaft twisting under combustion loads and, if left uncontrolled, can lead to cracks or complete crankshaft failure.

Features of QSC Vibration Dampers

• Available in multiple diameters, including 9.67” and 8.97” outside diameters.

• Precision-engineered with bolt-on design for secure fitment.

• Reduce wear on crankshaft bearings and prolong overall engine life.

Because vibration dampers degrade internally over time, replacing them as part of a major engine service is strongly recommended.

Gear Housing Gaskets

The gear housing is another critical area around the crankshaft that requires proper sealing. Our Cummins QSC gear housing gaskets provide a tight seal, preventing oil leaks and protecting the timing gears from debris.

• Designed for direct replacement on ISC, QSC, ISL, and QSL engines.

• Manufactured from durable materials to withstand heat and oil exposure.

• Completes the bottom-end rebuild alongside crankshafts, bearings, and seals.

Why Choose Diesel Pro Power for Cummins QSC Crankshaft Parts?

With more than 40,000 satisfied customers worldwide, Diesel Pro Power has become the go-to source for Cummins QSC parts. Our commitment includes:

• Worldwide shipping with fast turnaround times.

• Extensive inventory of crankshafts, bearings, seals, dampers, and gaskets.

• Dedicated customer support for part selection and technical questions.

• Reliable quality with every component built to OEM specifications or better.