Cylinder Heads & Related Components for Cummins 6CT 8.3 Engines

The Cummins 6CT 8.3 engine is a cornerstone of reliable performance in both industrial and marine applications. Known for its durability, simplicity, and broad versatility, this inline 6-cylinder diesel engine relies heavily on the integrity of its cylinder head to maintain compression, coolant flow, and proper valve function. At Diesel Pro Power, we supply a complete range of cylinder head components engineered to meet or exceed OEM specifications.

Whether you're rebuilding a 6C, 6CT, or 6CTA 8.3 engine, our selection of cylinder heads, valves, gaskets, bolts, and valve train components ensures your engine gets the attention it deserves—backed by quality, speed, and the satisfaction of over 40,000 customers worldwide.

Complete Cylinder Heads for Cummins 6CT Engines

We offer multiple configurations of fully assembled cylinder heads for Cummins 6CT engines. All heads come new and include factory-installed valves. The selection includes options with different air intake port sizes to match your specific application.

Cylinder Head Options:

• 16" Air Intake Cylinder Head (Non-Marine Use): A popular configuration for land-based engines. Comes complete with pre-installed valves and machined mating surfaces.

• 21" Air Intake Cylinder Head (Non-Marine Use): Ideal for engines with higher airflow requirements or upgraded turbo configurations.

• 21" Air Intake Cylinder Head (Marine Use): Built with corrosion-resistant components and designed to meet marine-grade durability standards.

These heads are direct replacements for Cummins 6C8.3, 6CT8.3, and 6CTA8.3 engines. Installation-ready and machined to OE tolerances, they eliminate the guesswork of rebuilding used castings.

Intake and Exhaust Valves

Proper airflow starts and ends with the valves. The intake and exhaust valves in your 6CT engine must withstand extreme temperatures and pressures over extended cycles. We carry high-quality replacements that match the material composition and geometry of Cummins OE parts.

Key Intake and Exhaust Valve Features:

• High-strength stainless steel for corrosion and heat resistance.

• Precision-ground valve stems for tight tolerance in valve guides.

• Hardened valve seats compatible with modern fuels and additives.

• Direct fit for 6C, 6CT, and 6CTA cylinder heads.

Whether you're replacing a single valve or rebuilding all six cylinders, Diesel Pro has the individual parts or kits to get the job done right.

Valve Springs and Rotators

Valve springs are critical in maintaining valve timing and sealing under high RPMs and engine load. Our 6CT valve springs are designed with proper spring tension and resistance to fatigue.

Available Components:

• Intake Valve Springs: Designed to handle the dynamic forces of air induction, optimized for non-turbo and turbocharged models.

• Exhaust Valve Rotators: These help evenly distribute wear on valve seats by rotating the exhaust valves during operation, extending both valve and seat life.

High-quality valve train components ensure smooth engine operation and reduce the risk of valve float or sticking under heavy load.

Cylinder Head Bolts and Fasteners

Cylinder head bolts are not reusable after engine teardown due to the torque-to-yield characteristics required in many Cummins applications. We stock head bolts for all 6CT configurations to ensure proper sealing and clamp force.

Head Bolt Configurations:

• Standard 12-bolt kits for earlier 6C engines.

• 14-bolt kits for later 6CTA and QSC variants.

Bolts are designed for even torque distribution and are manufactured with high-grade steel for thermal expansion compatibility. Always replace head bolts during head installation to maintain factory torque specs.

Cylinder Head Gaskets and Upper Gasket Sets

No top-end rebuild is complete without replacing the upper gaskets. Our Cummins 6CT gasket sets include all necessary seals to reassemble the cylinder head and its associated systems.

Available Gasket Solutions:

• Head Gaskets for standard horsepower ranges.

• Upper Gasket Sets for complete top-end sealing, including valve cover, intake manifold, gear housing, and EGR components (if equipped).

• Intake Connection Gaskets for tight, leak-free intake port sealing.

• Valve Cover Gaskets for long-lasting protection against oil seepage.

All gaskets are manufactured with advanced materials designed to resist heat, oil, coolant, and vibration common in diesel engine environments.

Valve Inserts, Valve Guides, and Valve Seals

Valve inserts (also called seats) are critical in ensuring longevity and performance of the cylinder head. Diesel Pro supplies both intake and exhaust valve inserts for the 6CTA engine family.

Key Supporting Components:

• Valve Inserts (Intake & Exhaust): Available in standard and oversize configurations for precise fitment.

• Valve Guides: Ensure accurate valve motion and prevent oil consumption due to valve stem wear.

• Valve Guide Seals: Prevent oil from leaking into the combustion chamber and burning off during engine operation.

Each part is engineered to resist wear in high-heat environments and is compatible with standard valve sizes for the 6C, 6CT, and 6CTA series.

Push Rods, Rocker Arm Nuts, and Additional Hardware

During a top-end rebuild or repair, other components like push rods and rocker arm hardware often require inspection and replacement. Diesel Pro carries:

• Push Rods specifically manufactured for the 6C, 6CT, and 6CTA engines.

• Heavy Hex Nuts used to adjust and secure rocker arms during valve lash settings.

• Temperature Switches and other critical sensors designed for compatibility with Cummins engines and others like Detroit Diesel and Caterpillar.

Having the correct and durable hardware is essential for maintaining valve timing and reducing the risk of premature top-end wear.

Gear Housing and Cover Gaskets

Supporting gaskets for the cylinder head and valve train include:

• Gear Cover Gaskets: Seals the timing gear area and prevents oil leaks.

• Gear Housing Gaskets: Provide tight seals between the engine block and the timing gear housing.

These parts are often overlooked in head rebuilds, but failure to replace them can lead to oil leaks and contamination over time.

Marine vs. Non-Marine Cylinder Head Differences

Cummins 6CT engines are used in a wide range of industrial and marine environments. Diesel Pro offers cylinder heads tailored for each:

• Marine Cylinder Heads: Feature corrosion-resistant materials and finishes, especially around water jackets and air intake ports. They often include configurations optimized for constant-load marine duty cycles.

• Non-Marine Cylinder Heads: Focused on industrial and on-road applications, optimized for variable RPM use and simpler cooling systems.

Selecting the correct head ensures long service life and reduces the risk of internal corrosion or thermal failure in your application.

Why Buy Your 6CT Cylinder Head Parts from Diesel Pro?

• Precision-Fit Parts: All components meet or exceed Cummins specifications.

• Rapid Global Shipping: With inventory ready to ship, you can reduce downtime no matter where your engine operates.

• Expert Support: Our diesel parts specialists can walk you through installation, compatibility, and troubleshooting.

With over 40,000 satisfied customers and decades of experience supplying professional rebuilders and operators, Diesel Pro Power is your trusted source for Cummins engine parts.