Cylinder Heads & Related Components For Cummins 4BT Engines

The Cummins 4BT 3.9L engine, a naturally aspirated inline 4-cylinder powerhouse, is widely recognized for its simplicity, rugged design, and long-term reliability in industrial and marine applications. One of the most critical components of this engine is the cylinder head assembly. The health of the cylinder head directly impacts engine performance, fuel efficiency, combustion, and cooling effectiveness. At Diesel Pro Power, we provide a complete range of Cummins 4BT cylinder heads and related components, all backed by fast shipping, guaranteed quality, and over 40,000 satisfied customers worldwide.

New Cylinder Head Assemblies for Cummins 4BT Engines

We offer new cylinder heads for Cummins 4BT 3.9 engines that are built to OEM specifications and include the valves and springs already installed. These assemblies simplify installation and ensure a perfect fit for a broad range of industrial, agricultural, and marine equipment that utilizes the 4BT engine platform.

Key Features of Our Cylinder Head Assemblies:

• Fully assembled with intake and exhaust valves, valve springs, and injector sleeves pre-installed

• Available with 7mm or 9mm injector tube configurations, depending on the version of your 4BT engine

• Designed for compatibility with naturally aspirated 4BT 3.9L engines

• Built from high-strength cast iron for durability under extreme conditions

• Machined for precise fitment, ensuring long-term sealing and compression integrity

Choosing the correct injector tube size (7mm or 9mm) is critical. If you are unsure which type your engine requires, Diesel Pro Power’s technical support team can guide you based on your engine serial number or cylinder head casting.

Cylinder Head Valves for 4BT Engines

Valves are key components that control air intake and exhaust flow in the combustion chamber. Over time, they can wear, warp, or become pitted, especially under high heat or poor lubrication conditions.

Intake Valves

Our intake valves are made from high-quality alloy steel to handle the heat of combustion gases and intake flow. These valves deliver reliable sealing performance and proper airflow regulation.

Exhaust Valves

Exhaust valves are typically subject to even greater heat and stress than intake valves. Diesel Pro Power offers heavy-duty exhaust valves that are engineered for long-term use even in severe-duty conditions like marine propulsion or generator sets.

Each 4BT cylinder requires one intake and one exhaust valve per cylinder—for a total of four of each in a complete engine rebuild.

Valve Rotators and Spring Assemblies

Valve rotators play a crucial role in promoting even valve wear and extending service life. These components sit on top of the valve spring and rotate the valve slightly each time it opens and closes, minimizing carbon buildup and hot spots.

Our rotators are precision-machined to OEM standards and are ideal replacements for worn or sticking components. We also stock heavy-duty valve springs designed for proper compression and valve timing.

Cylinder Head Bolts

Using high-quality bolts is essential when replacing or reinstalling a cylinder head. We provide both short (70mm) and long (120mm) bolts for the Cummins 4BT engine. These fasteners are manufactured to handle high torque and clamping force without stretching or shearing.

Bolt Quantities:

• Short bolts (70mm): typically used in specific cylinder locations

• Long bolts (120mm): 10 per head for 4BT engines

Always follow Cummins torque specifications and sequences during installation to ensure even pressure and prevent head gasket failure.

Head Gaskets and Upper Gasket Sets

Head Gasket Options

We offer standard and oversize Cummins 4BT head gaskets made from multilayer steel (MLS) and graphite-based materials. These gaskets provide superior sealing under high combustion pressure and are resistant to coolant or oil intrusion.

Upper Gasket Sets

Our upper gasket kits include everything needed to reseal the top end of your engine, including:

• Cylinder head gasket

• Valve cover gasket

• Intake and exhaust manifold gaskets

• Thermostat housing gasket

• Injector seal washers

Oversized gasket sets (0.25mm) are available for engines that have been resurfaced or machined.

Valve Cover Gaskets and Seals

Valve cover gaskets keep oil inside the engine and prevent it from leaking onto the cylinder head or exhaust manifold. We carry valve cover gaskets designed specifically for the 4B’s cast aluminum or stamped steel covers.

We also provide:

• Valve stem seals

• Valve guide seals (intake & exhaust)

• Push rod cover gaskets

These seals prevent oil from entering the combustion chamber and ensure optimal lubrication inside the cylinder head.

Valve Seats and Guides

Worn guides or seats can lead to valve misalignment, excessive oil consumption, and reduced compression. Diesel Pro Power offers:

• Intake valve inserts

• Exhaust valve inserts

• Valve guides for both intake and exhaust applications

Each insert is engineered for maximum heat resistance and long-term sealing.

Push Rods and Valve Train Hardware

Push rods are responsible for transferring camshaft motion to the rocker arms. A bent or damaged push rod can throw off valve timing and lead to poor engine performance. We provide:

• Heat-treated push rods

• Heavy-duty hex nuts for rocker arm adjustment

• Valve keepers and retainers

Each piece is machined to precise tolerances for a drop-in fit during reassembly.

Fuel Manifold for 4BT Engines

We also carry fuel manifolds for 4B engines, which serve as the central distribution channel for high-pressure fuel delivery to each injector. These are particularly important in mechanical fuel systems where even fuel delivery is critical for smooth operation.

Maintenance Tips for 4BT Cylinder Heads

To ensure a long life for your 4BT cylinder head, consider the following tips:

• Always check for cracks in the casting, especially between valve seats

• Replace injector tubes when signs of pitting, corrosion, or fuel leakage are visible

• Resurface the head when reusing it to ensure a flat mating surface

• Check valve spring tension and replace springs that have lost elasticity

• Use new head bolts and follow torque specs to prevent uneven clamping

Neglecting any of these areas can lead to premature gasket failure, low compression, or coolant leakage.

Why Buy Your 4BT Cylinder Head from Diesel Pro Power?

With more than 40,000 satisfied customers worldwide, Diesel Pro Power is one of the most trusted suppliers of Cummins 4BT engine parts online. When you purchase from us, you get:

• High-quality parts built to OEM specs

• Dedicated support team ready to assist with fitment questions

• Same-day shipping on in-stock items

• Fast worldwide delivery

• No core charges for most parts

• Secure online ordering

Our inventory is tailored for marine, industrial, and stationary applications—not automotive swaps—ensuring you're getting parts that meet the durability demands of commercial equipment.

Engine Applications for Cummins 4BT Cylinder Heads

Cummins 4BT engines are used in a wide variety of applications:

• Marine generators and auxiliary engines

• Agricultural tractors and irrigation pumps

• Industrial compressors

• Light construction equipment

• Stationary power units

Whether you're working on a commercial vessel, farming machinery, or a backup generator system, the quality of your cylinder head can make or break your engine's performance. Diesel Pro Power has the components you need to keep your Cummins 4BT running strong.