Cylinder Heads & Related Components for Cummins ISL Engines

The Cummins ISL engine is a proven workhorse across marine, industrial, and commercial vehicle applications. When it comes time to perform a top-end overhaul or cylinder head replacement, Diesel Pro Power offers a complete line of components engineered for precise fit, long service life, and exceptional thermal and mechanical durability.

From fully assembled cylinder heads to valve train components, gasket sets, and temperature sensors, we stock everything needed for a proper top-end refresh. With over 40,000 satisfied customers around the globe, Diesel Pro Power is your trusted supplier for Cummins ISL rebuild parts.

Complete Cylinder Head Assembly for Cummins ISL

We stock a new Cummins ISL cylinder head pre-assembled with intake and exhaust valves already installed. This direct-replacement head is machined to exact OEM specifications and includes precision-seated valves and springs, making it an ideal choice for a top-end rebuild or a swap on a damaged head.

Whether your ISL engine is powering an industrial generator, commercial vessel, or on-highway equipment, this cylinder head restores peak compression and flow efficiency. Built from high-quality cast iron and pressure tested for internal integrity, it's a dependable solution for heavy-duty environments.

Cylinder Head Bolts for Cummins ISL

The ISL engine uses two distinct types of cylinder head bolts to secure the head to the block and ensure proper clamping force across the combustion chambers. These bolts must be torqued precisely and replaced during any cylinder head removal to maintain sealing integrity and prevent uneven stress distribution.

We offer both primary bolts and secondary bolts used on certain ISL configurations, including variants shared with QSL, M11, and QSM platforms. All hardware is manufactured to exact tensile specifications to handle the pressures of modern diesel combustion.

Upper Gasket Sets for Cummins ISL Engines

A proper top-end rebuild requires replacing every sealing surface above the block. Our complete upper gasket sets for the ISL include:

Cylinder head gasket
Intake manifold gasket
Exhaust manifold gasket
Rocker cover gasket
Valve cover gaskets (multiple styles)
Thermostat housing gasket
Injector tube seals
Coolant and oil passage O-rings

We offer several gasket set variations to match your specific ISL configuration:

For CAPS Fuel Systems (CM554 ECM)

This version is ideal for earlier ISL engines equipped with Cummins Accumulator Pump System fuel delivery.

For HPCR Engines with CM850

High-pressure common rail ISL models benefit from this gasket set, which is tailored for their updated sealing requirements.

For EGR ISL Engines

If your engine uses exhaust gas recirculation (EGR), select the gasket set designed for proper exhaust and coolant sealing in EGR-equipped configurations.

Standard Upper Gasket Set for Under 450 HP

Perfect for mid-range power ISL engines used in industrial or marine auxiliary power roles. Includes all required seals and gaskets for engines producing 450 horsepower or less.

Intake & Exhaust Valves for Cummins ISL

The ISL cylinder head contains eight intake valves and eight exhaust valves—each designed to operate under high pressure, extreme temperatures, and corrosive gas exposure. We carry both types:

ISL Intake Valves

Made from heat-treated steel alloys to handle hot intake air mixed with fuel vapor. Precision-ground stems and faces ensure excellent airflow and seat contact.

ISL Exhaust Valves

Manufactured from high-nickel alloys for resistance to thermal fatigue and oxidation. Designed for long valve life even under extreme duty cycles.

Valve Springs for ISL Cylinder Head

The valve springs used in Cummins ISL engines control the opening and closing motion of both intake and exhaust valves. They provide the necessary tension to keep the valve seated at the right time during the engine cycle. Our ISL valve springs are engineered to resist fatigue and maintain their original spring rate over thousands of hours of operation.

Valve Seat Inserts for Cummins ISL Engines

We offer both intake and exhaust valve inserts—also known as valve seats. These hardened rings are press-fitted into the cylinder head and provide the surface on which the valve rests. We stock both standard and oversize insert options to restore sealing and prolong cylinder head life after multiple valve replacements or seat machining operations.

Valve Cover Gaskets for ISL Engines

The ISL engine is available in several rocker cover designs. We carry valve cover gaskets for both 5-bolt and 8-bolt covers. These gaskets prevent oil leaks from the rocker housing area and are essential for maintaining oil cleanliness in the valvetrain.

Always inspect and replace valve cover gaskets during top-end work or if you detect oil seeping from the top of the cylinder head.

Additional Seals, Guides & Valve Components

Diesel Pro Power also stocks the smaller yet essential components needed to support a professional-grade rebuild:

Valve guides (to center the valve stem)
Valve guide seals (to prevent oil entry into the combustion chamber)
O-rings and injector seals (for leak-proof sealing)
Miscellaneous intake/exhaust hardware

Each component is tested for material quality and dimensional precision, ensuring that your rebuild meets or exceeds OEM performance.

Temperature Switch for Cummins ISL

Our temperature switch is a critical component in safeguarding your engine from overheating. Designed for use with Cummins, Detroit Diesel, and Caterpillar engines, it activates at a specific temperature threshold (205°F) and can be configured to trigger alarms or shutdown procedures.

Threaded for standard 1/2" NPT fittings, this sensor is compatible with most marine and industrial ISL installations.

Why Diesel Pro Power is the Right Choice for Your ISL Top-End Rebuild

Parts in Stock – Fast fulfillment and worldwide shipping.
Marine & Industrial Expertise – Our team understands the environments your engine operates in.
One-Stop Solution – Get everything you need for an ISL cylinder head rebuild in one place.
Proven Reliability – Trusted by fleets, service yards, power plants, and vessel owners in over 200 countries.

We’ve helped tens of thousands of professionals complete top-end overhauls quickly, confidently, and cost-effectively.

Supported Cummins ISL Applications

The ISL engine powers a wide range of heavy-duty diesel equipment, including:

Commercial marine propulsion and auxiliary power units
Industrial pumps and compressors
Standby and prime power generators
Transit buses and vocational trucks
Agricultural and forestry machinery

Our parts catalog is designed to support all major ISL variants, regardless of their emission system (CAPS, HPCR, EGR, etc.) or power rating.

ISL Cylinder Head Rebuild Tips

To ensure lasting results on your top-end rebuild, follow these best practices:

Always use new head bolts—reusing old fasteners risks incorrect torque values.
Clean and inspect the block surface for warping or damage before reinstalling the head.
Confirm gasket compatibility with your fuel system (CAPS or HPCR).
Replace all seals, springs, and valve-related components in one go.
Pressure test the cylinder head prior to installation to catch cracks or porosity issues.
Use proper torque sequence and angle values as specified by Cummins service manuals.

Cummins Exhaust Valve

Frequently added by mechanics