Cylinder Heads & Components for Cummins ISB 5.9 Engines

The Cummins ISB 5.9 engine is one of the most popular and reliable diesel engines in both industrial and marine applications. At Diesel Pro Power, we carry a full inventory of cylinder heads and related components to help you keep your ISB 5.9 running strong. Whether you're replacing a worn-out head or doing a complete top-end rebuild, our cylinder head section includes all the critical parts you need—new heads, valves, bolts, gaskets, and more.

New Cylinder Heads for Cummins ISB 5.9

Cylinder Head with Valves and Springs – Marine Application

We offer a brand-new cylinder head assembly for the Cummins ISB 5.9 that includes pre-installed valves and springs. This head is built for marine applications and comes ready to install, saving you time and labor. Constructed to OEM standards and built for durability in marine environments, this component is ideal for high-load, continuous-duty engines that demand precision and resilience.

Cylinder Head with Valves – Industrial Applications

For land-based or industrial uses, we also offer a fully assembled new cylinder head with valves already installed. This unit is compatible with the Cummins ISB 5.9 platform and built for non-marine applications such as power generation, construction equipment, and agricultural machinery. This drop-in replacement head provides OE-level fitment and performance, giving you confidence in both reliability and service life.

Intake & Exhaust Valves for Cummins ISB 5.9

Replacing your cylinder head? It’s critical to install fresh intake and exhaust valves to restore full compression, prevent valve leaks, and extend engine life. Below are the components you’ll need for a complete valve job.

Intake Valves

Our intake valves for the ISB 5.9 are built to handle the high intake airflows typical of diesel combustion. Made from heat-resistant alloys and engineered to OEM dimensions, these valves are designed to maintain air-tight sealing throughout the engine’s power cycles. Each intake valve is precision-ground and quality-tested to ensure optimal seat contact and long-term durability.

Exhaust Valves

We supply OEM-equivalent exhaust valves designed to handle high-temperature exhaust gasses. These valves are equipped with valve keepers for secure fitment and are treated for resistance to wear and corrosion. When replacing the cylinder head or refreshing the valvetrain, new exhaust valves are essential to avoid premature seat wear and exhaust leaks.

Valve Kits (with Stem Seals)

Our complete exhaust valve kits come with all necessary hardware and integrated stem seals. Stem seals help prevent oil from leaking into the combustion chamber and are a must-have for high-performance and marine engines where oil control is critical.

Cylinder Head Hardware

Cylinder head installation requires reliable and precise hardware. Reusing old bolts is never recommended due to torque fatigue and elongation over time. Diesel Pro Power offers the essential bolts and hardware you’ll need for your ISB 5.9 head installation.

Cylinder Head Bolts

We carry two primary types of head bolts used in the ISB 5.9 platform:

• 70 mm head bolts for older generation or smaller bore heads (compatible with earlier 4B and 6B engines).

• 131 mm head bolts for standard ISB 5.9 heads, used in most mid-2000s models.

These bolts are high-tensile fasteners specifically designed for high-pressure diesel engines. Always use new bolts and follow Cummins' torque specs for proper clamping force and gasket seal integrity.

Cylinder Head Gaskets and Sealants

An engine is only as strong as the seal between its cylinder head and block. That's why it’s crucial to use premium-quality gasket sets designed for your specific ISB 5.9 variant.

Upper Gasket Set – Non-EGR Engines

For non-EGR Cummins ISB 5.9 engines, we supply a comprehensive upper gasket set that includes:

• Cylinder head gasket

• Valve cover gasket

• Intake and exhaust manifold gaskets

• Valve stem seals

• Miscellaneous seals and O-rings

This set is ideal for traditional mechanical or low-emissions engines commonly used in older industrial or generator setups.

Upper Gasket Set – High Pressure Common Rail (EGR Engines)

Modern ISB 5.9 engines that include exhaust gas recirculation and high-pressure common rail fuel systems require a different gasket set due to the additional plumbing and component sealing. Our EGR-compatible set covers all necessary gaskets and seals for:

• EGR cooler

• High-pressure fuel connectors

• Turbo mounting flange

• Updated valve cover gaskets

Valve Cover Gaskets

Valve cover gaskets are often overlooked but play a key role in preventing oil leaks from the top of your engine. Our valve cover gaskets are precision-molded to fit ISB and QSB 5.9 cylinder heads with exact tolerance, ensuring a snug seal. Ideal for reassembly after a cylinder head or valve train service.

Valve Springs

High-quality valve springs help maintain proper valve timing and prevent valve float, especially in high-RPM or heavy-load conditions. We carry OEM-spec valve springs for ISB 5.9 applications, compatible with both marine and land-based configurations. These springs are engineered for consistent pressure and long-lasting performance.

Valve Inserts

Valve seat inserts are installed in the cylinder head to provide a hardened seating surface for the intake and exhaust valves. Over time, these seats can wear, leading to poor sealing and compression loss. Diesel Pro Power offers:

• Intake valve inserts – hardened for high airflow endurance

• Exhaust valve inserts – built to withstand extreme heat and chemical corrosion

Both types are available separately for head reconditioning or new installations.

Valve Seals

Oil control is critical in diesel engines, especially where the valve guides meet the valve stems. We offer:

• Intake valve seals

• Exhaust valve seals
  These seals prevent oil from migrating down into the combustion chamber, reducing oil consumption and emissions. Each seal is made from heat-resistant synthetic rubber and reinforced with stainless steel spring tensioners.

Fuel Manifold

While not a cylinder head component per se, the fuel manifold (fuel rail) supports direct injection on ISB and QSB engines. Our fuel manifolds are precision-machined and pressure-tested, ensuring proper fuel delivery to each injector. For older engines that share head and fuel rail mounting surfaces, replacing a corroded or cracked manifold is essential during cylinder head service.

Temperature Switch

For marine and industrial diesel engines, proper thermal regulation is essential. The temperature switch we carry is compatible with Cummins, Detroit Diesel, and Caterpillar platforms. It activates at 205°F and uses a 1/2" NPT thread, allowing for direct installation into coolant ports on the cylinder head or thermostat housing.

Why Choose Diesel Pro Power?

• Trusted by 40,000+ customers worldwide

• All components tested for quality and fitment

• Fast shipping and live customer support

• Marine and industrial diesel specialists