FORD RF3S4G Duratech Cylinder Head 2.3L

( Brand: Ford ), ( Manufacturer Part Number: RF3S4G ), ( Type: Cylinder Head ), ( Items Included: No ), ( Material: Aluminum ), ( Finish: Pcd ), ( Country Of Origin: United States )

Review FORD Mazda Remanufactured 2.3l Duratech Cylinder Head Casting fits 2004–2011

The **Ford/Mazda RF3S4G 2.3L Duratech Cylinder Head (2004 2011)** is a meticulously engineered, high-performance component designed to deliver exceptional reliability and power output for the iconic Zetec-based engines found in vehicles like the Ford Focus ST, Mazda RX-8, and other performance-oriented applications. Crafted from premium cast iron, this cylinder head is built to withstand the demands of aggressive driving, high RPM operation, and sustained power delivery, making it an ideal choice for both stock and modified setups. The head features a **four-valve, dual overhead camshaft (DOHC) design**, with each cylinder controlled by a pair of intake and exhaust valves, ensuring optimal airflow and combustion efficiency. The **intake valves** are typically 1.45 inches in diameter, while the **exhaust valves** measure around 1.3 inches, allowing for precise tuning and the potential for aftermarket upgrades such as larger valves, stiffer springs, or high-flow heads for increased horsepower and torque. The **camshafts** are precision-machined to maintain smooth operation, with the intake cam designed for aggressive lift and duration to maximize airflow into the combustion chamber, while the exhaust cam is optimized for efficient scavenging to reduce backpressure and improve exhaust flow.

One of the standout features of this cylinder head is its **integrated valve cover**, which not only houses the camshafts and rocker arms but also serves as a protective barrier against contaminants, reducing the risk of oil leaks and ensuring longevity. The **rocker arm assembly** is mounted on a robust **tappet bridge**, which supports the hydraulic or solid lifters depending on the application, allowing for minimal valve float and consistent valve lash adjustment. The **combustion chambers** are carefully shaped to promote efficient fuel-air mixing and combustion, reducing detonation risk while maximizing power output. Additionally, the head incorporates **high-quality cast iron construction** with reinforced deck surfaces to prevent warping under high heat loads, a common issue in high-performance engines. The **spark plug holes** are strategically positioned for optimal ignition timing, while the **oil passages** are designed to ensure adequate lubrication to all critical components, including the camshafts, lifters, and rocker arms.

For enthusiasts looking to push their engines beyond stock specifications, the **RF3S4G Duratech cylinder head** offers a solid foundation for modifications. It can accommodate **aftermarket headers, high-flow intake manifolds, and performance camshafts**, allowing for significant gains in horsepower and torque. The head s **threaded spark plug holes** and **exhaust port design** make it well-suited for forced induction applications, such as turbocharging or supercharging, provided proper supporting modifications (such as upgraded fueling and cooling) are implemented. The **exhaust ports** are contoured to minimize turbulence and improve flow, while the **intake ports** are designed to funnel air smoothly into the combustion chamber, enhancing volumetric efficiency. Whether used in a **stock tune, mild build, or high-performance application**, this cylinder head delivers a balance of strength, durability, and performance that is hard to match.

When maintaining or modifying this cylinder head, it is crucial to follow proper procedures, including **valve seat machining, port matching, and head gasket installation** to ensure a leak-free and efficient seal. The **head gasket** must be of high quality, such as a **copper-faced or multi-layer steel (MLS) gasket**, to prevent warping and ensure proper compression. Additionally, **proper head stud torque specifications** must be adhered to during assembly to avoid overtightening or under-torquing, which can lead to warping or head gasket failure. For those seeking the absolute best performance, **porting and polishing** the intake and exhaust ports can further enhance airflow, though this should be done by a professional to avoid compromising the head s structural integrity. Overall, the **Ford/Mazda RF3S4G 2.3L Duratech cylinder head (2004 2011)** remains a legendary component, offering a perfect blend of reliability, performance, and adaptability for both stock and modified applications.

### **Pros and Cons of Buying a Ford/Mazda RF3S4G 2.3L Duratech Cylinder Head (2004 2011)**

#### **Pros**

1. **Proven Reliability** The Duratech engine (used in the Ford Focus, Mazda3, and Mercury V6) is known for its durability when properly maintained. Many examples with low mileage or well-documented service histories run reliably for well over 200,000 miles.

2. **Affordable Parts and Labor** Being a common engine in Ford and Mazda vehicles, parts (especially cylinder heads) are widely available and reasonably priced. Labor costs are also competitive compared to more exotic or rare engines.

3. **Good Performance for the Price** The 2.3L Duratech produces around **140 160 horsepower** (depending on year and modifications), which is sufficient for daily driving, light towing, or even light performance tuning. It handles well in stock form and responds well to upgrades like intake, exhaust, or camshaft swaps.

4. **Modular and Upgradable** The engine is modular, meaning many components (like the cylinder head, block, and intake manifold) are interchangeable with other Duratech variants (e.g., the 2.5L or 3.0L). This makes upgrades and modifications straightforward.

5. **Strong Aftermarket Support** There is a robust aftermarket for this engine, including performance parts (e.g., headers, turbo kits, fuel systems), tuning options, and rebuild kits. This makes it easier to customize or restore if needed.

6. **Fuel Efficiency** Stock versions achieve **20 25 MPG in the city and 28 32 MPG on the highway**, which is decent for a naturally aspirated engine of this size. With minor upgrades, efficiency can improve further.

7. **Common in Used Market** Due to its popularity, you ll find plenty of used examples at reasonable prices, especially in the **$1,000 $3,000 range** for a complete engine or **$500 $1,500** for just the cylinder head (depending on condition).

8. **Good for Beginners** If you're new to engine work, the Duratech is a good learning platform because it s not overly complex, and many resources (forums, YouTube tutorials) are available for repairs and modifications.

---

#### **Cons**

1. **Potential for Oil Consumption** Some Duratech engines, especially those with higher mileage, develop **oil leaks or excessive oil consumption** due to worn valve seals, piston rings, or PCV system issues. Regular oil changes and inspections are a must.

2. **Timing Chain Wear** Unlike chain-driven engines with tensioners, the Duratech uses a **timing belt** (on some models) or a **timing chain** (on others). If the chain stretches or the tensioner fails, it can cause **valve train damage**, leading to expensive repairs if not caught early.

3. **Head Gasket Failures** While not as notorious as some engines, the Duratech can suffer from **head gasket leaks**, especially if overheating occurs. Proper cooling system maintenance is critical.

4. **Electrical and Sensor Issues** Some models (particularly early 2004 2006) have had **faulty sensors (MAF, crankshaft position)** or wiring problems, which can lead to rough idling, check engine lights, or poor performance. Rebuilding or replacing these components may be necessary.

5. **Transmission Compatibility** If you're installing this engine into a different vehicle, you ll need to ensure **transmission compatibility** (e.g., a 5-speed manual or automatic may require modifications like a different bellhousing or flexplate).

6. **Turbocharged Variants Are Riskier** While naturally aspirated Duratechs are solid, **turbocharged versions** (found in some Focus STs) are more prone to **turbo failure, oil leaks, and head gasket issues** due to increased stress. If you're considering a turbo model, expect higher maintenance costs.

7. **Rust and Corrosion** Older examples (especially from snowy or coastal climates) may suffer from **rust in the exhaust manifold, oil pan, or suspension**, which can lead to leaks or structural weakness.

8. **Depreciation** While the engine itself is reliable, the **vehicle it s in** (e.g., a used Focus or Mazda3) may depreciate quickly if not well-maintained. Some models (like the early Focus) have had reliability issues unrelated to the engine.

---

### **Conclusion**

The **Ford/Mazda 2.3L Duratech cylinder head (2004 2011)** is a **solid, cost-effective choice** for those looking for a **reliable, upgradeable, and well-supported engine**. It excels in **daily driving, light performance tuning, and DIY projects** due to its availability of parts and aftermarket support.

- **Inspect for oil leaks, timing belt/chain condition, and head gasket integrity.**

- **Check for proper maintenance history** (oil changes, cooling system care, sensor replacements).

- **Be prepared for potential issues like oil consumption or electrical gremlins**, which can be managed with regular upkeep.

- **Avoid turbocharged versions unless you re experienced**, as they carry higher risk.

If you're **mechanically inclined, on a budget, or looking for a project engine**, the Duratech is a **strong recommendation**. If you want **plug-and-play reliability with minimal hassle**, consider a **proven used engine with a clean history** rather than a high-mileage or neglected example.

### **Final Recommendation**

You need a **reliable, affordable, and upgradeable** engine for a project car.

You re willing to **inspect it thoroughly** for wear and tear.

You plan to **maintain it properly** (oil changes, cooling system checks, timing belt replacement).

You re okay with **some potential quirks** (oil consumption, sensors) that can be fixed with basic maintenance.

You want a **completely hassle-free** engine with no known issues.

You re buying a **high-mileage example without documentation**.

You re not comfortable with **basic engine maintenance** (oil changes, belt replacements).

You re targeting a **turbocharged version** without experience in turbo engine care.

- **Restoring a classic or modern Ford/Mazda vehicle.**

- **Building a lightweight, fuel-efficient hot rod or street car.**

- **A beginner s engine project** (due to availability of parts and tutorials).

- **A budget-friendly alternative to more expensive engines** (e.g., LS, Gen V V8).

**Final Verdict:** **A great engine for the right buyer reliable, affordable, and full of potential with the right care.**

Details:

Please pack the cores using same packaging and cover them as best you can. Spring valve. Inspected and pressure-tested components. The condition does not matter as long they are well-packed to avoid further damage during transportation.

CASTING RF3546-6090. Seat and guide work performed throughout. No Core Deposit required. Just send all of the parts.

Fl Engines 4 Less. Mazda 3 2.3L 2004 2009. Resurfaced to specifications with PCD for the best finish on aluminum. Labor is excluded.

part #: rf3s4g prices

• $349.99-$449.99

specifications cylinderheapar:

• for makes: Mazda, Ford
• for years: 2004-2011
• brand: Ford
• mpn: Rf3s4g
• type: Cylinder Head
• items included: No
• material: Aluminum
• finish: Pcd
• country of origin: United States

payments cylinderheapar:

• other
• credit card: Discover
• wallet: Google-pay

seller cylinderheapar:

• city: Hialeah, Florida
• rating: 99.3%
• # reviews: 4554

returns cylinderheapar:

• paid by: Buyer
• time: 30 Days
• policy: Returns Accepted

shipping cylinderheapar:

• type: Fixed
• carrier: UPS
• cost: $80.00
• class: Standard
• service: UPS Ground
• transit: 2-6 Days

general cylinderheapar:

• Car Truck Parts Accessories > Engines Engine Parts > Cylinder Heads
• condition: Remanufactured

offer cylinderheapar:

• quantity: 1
• started: March 17, 2026
• availability: In Stock
• options: Ship-to-home
• sold: 0

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