Cylinder Heads & Related Components for Cummins 4BTA 3.9 Engines

The Cummins 4BTA engine is one of the most widely used industrial diesel engines in the world, known for its reliability, compact design, and exceptional performance in marine, agricultural, and construction applications. Whether you’re performing a top-end rebuild or replacing individual head components due to wear or overheating, having access to the correct cylinder head and associated parts is critical to maintaining engine efficiency and longevity.

At Diesel Pro Power, we provide new cylinder heads for the 4BTA 3.9 engine, already equipped with valves and valve springs. In addition to complete cylinder heads, we offer all the essential components you’ll need for repairs or replacement—including valves, inserts, guides, seals, and gaskets.

Complete Cylinder Heads for Cummins 4BTA

New Cylinder Heads with Valves and Springs

Our new cylinder heads for Cummins 4BTA engines come fully assembled with intake and exhaust valves, valve springs, and injector tube inserts. Two injector tube sizes are available—7mm and 9mm—so be sure to match your current head when choosing a replacement. These heads are direct replacements, machined to OEM specifications, and built for both marine and industrial use.

Key Features:

• Fully assembled head with valves and valve springs

• Pre-installed injector sleeves (7mm or 9mm available)

• Compatible with 4B, 4BT, and 4BTA 3.9-liter engines

• Designed for marine and industrial performance

• Ready for immediate installation with minimal prep

Replacing the entire head is often the most efficient option when damage from overheating, cracking, or warping is too severe to repair. If your engine exhibits symptoms like coolant in the oil, white exhaust smoke, or excessive blow-by, inspecting and replacing the head may be the best course of action.

Valve Train Components

The cylinder head functions as a complex housing for intake and exhaust valves, which allow the engine to draw in air and expel combustion gases. Over time, components in the valve train experience wear due to thermal cycling and high operating pressures. We carry individual valve components for targeted repairs.

Intake Valves

Each intake valve plays a vital role in allowing clean air to enter the combustion chamber. Replacing intake valves is necessary when they show signs of pitting, burning, or excessive wear around the valve seat or stem.

Exhaust Valves

The exhaust valves evacuate high-temperature gases post-combustion. Because they endure more heat than intake valves, exhaust valves typically wear faster and may need replacement during top-end overhauls. We recommend inspecting them for signs of burning, warping, or seat damage.

Valve Rotators

Valve rotators reduce localized wear by ensuring even rotation of the valves during operation. If your engine is experiencing uneven compression or abnormal valve noise, worn-out rotators may be to blame.

Cylinder Head Bolts & Torque Hardware

Correct torque and clamping force are critical when installing a new head. We provide factory-spec head bolts for 4BTA engines, available in both 70mm and 120mm lengths depending on head design. Always replace head bolts during reassembly, as they are torque-to-yield and should not be reused.

Cylinder Head Bolt Specs:

• 70mm bolts: Used per cylinder

• 120mm bolts: Used for securing each head

• OEM-grade tensile strength for thermal cycling and high-pressure environments

Torque the bolts in the correct sequence and to factory specs using a calibrated torque wrench. Improper clamping can result in head gasket failure or uneven sealing, which may lead to compression loss or coolant intrusion.

Gasket Sets and Seals

A quality seal between the head and engine block is crucial to prevent coolant or oil leaks and ensure proper combustion. We offer standard and oversize upper gasket sets tailored for the Cummins 4BTA engine. Oversize gaskets are used when the head or block surfaces have been resurfaced.

Upper Gasket Sets

• Standard gaskets for stock applications

• Oversize gaskets (0.25mm) for resurfaced blocks or heads

• Includes intake manifold, exhaust manifold, and valve cover gaskets

Head Gaskets

Our head gaskets are manufactured to exact Cummins specifications, ensuring long-lasting sealing performance. Whether you're doing a top-end overhaul or just replacing a leaking gasket, installing a new head gasket is a mandatory step.

Valve Cover Gaskets

Valve cover gaskets prevent oil seepage from the top of the engine. A cracked or worn gasket can lead to messy oil leaks and should be replaced during any head service.

Valve Springs, Inserts, and Guides

Valve-related hardware experiences constant stress and should be examined closely during cylinder head work.

Valve Springs

Valve springs maintain the timing and pressure of valve operation. Weak or damaged springs can cause valve float and poor engine performance. We carry new valve springs for both intake and exhaust applications.

Valve Inserts

Inserts provide the sealing surface for the valves. If your cylinder head has been subject to high heat or repeated machining, the inserts may need to be replaced.

• Intake valve inserts: Provide a hard surface for valve seating

• Exhaust valve inserts: Withstand high heat and gas pressure

Valve Guides

Guides control valve stem movement and help maintain proper valve alignment. Excessive clearance in the guide results in valve instability, loss of compression, and increased oil consumption.

• Intake and exhaust valve guides available individually

• Replace as needed during valve service or reconditioning

Valve Guide Seals

Valve guide seals ensure oil does not leak down the valve stems into the combustion chamber. Old or brittle seals should be replaced any time the head is removed or rebuilt.

Push Rods and Related Hardware

Push rods transmit motion from the camshaft to the rocker arms and valves. Bent, worn, or damaged push rods can cause misfires, valve noise, and poor combustion. Be sure to inspect them when servicing the head.

Push Rods

• Heat-treated steel construction

• Designed for optimal straightness and stiffness

• Compatible with 4B, 4BT, and 4BTA engines

Push Rod Cover Gaskets

These gaskets maintain a seal around the push rod cover. A leak in this area can result in oil seepage near the rocker arms and valve train.

Fuel System Components on Cylinder Head

Some components of the fuel system, including the fuel manifold and injector sleeves, are mounted directly to the cylinder head.

Fuel Manifold

The fuel manifold distributes fuel evenly to each injector. If your engine shows signs of uneven fueling or cylinder imbalance, inspecting or replacing the fuel manifold may resolve the issue.

Rocker Arm Hardware

To complete a top-end overhaul, you’ll need fasteners and adjustment hardware for the rocker arms.

Heavy Hexagon Nuts

These nuts secure the rocker arm adjustment screws and ensure consistent valve lash. It’s important to check these for stripping or wear and replace them if they no longer provide a snug fit.

Temperature Sensors

Temperature sensors mounted in the cylinder head provide critical engine temperature data for safe operation.

Temperature Switches

Used across multiple engine types including Cummins and Detroit Diesel, the temperature switch closes at a specific temperature (usually around 205°F), signaling the need for cooling action or triggering alarms.

When to Replace a Cummins 4BTA Cylinder Head

Overheating, cracks, and long-term wear are the most common causes of cylinder head failure. Below are some signs that indicate it may be time to replace or service the head:

• White smoke in the exhaust (coolant leak into combustion chamber)

• Coolant in oil (milky oil)

• Overheating

• Poor compression in one or more cylinders

• Visible cracks on the exterior or between valves

• Burnt or pitted valves

Always pressure test the head and inspect flatness before deciding whether to reuse or replace it. Our new heads come ready to install and are machined to OEM tolerances.

Why Diesel Pro Power?

With over 40,000 satisfied customers worldwide, Diesel Pro Power is the trusted source for Cummins 4BTA cylinder head parts. We offer fast shipping, excellent customer service, and a complete inventory of new and hard-to-find components for Cummins engines.