HONDA 306-50408D Engine Cylinder Head 1.5L

( Model: CR-Z ), ( Part Type: Engine Cylinder Head ), ( Conditions Options: 4, 1.5 ), ( Genuine Oem: Yes ), ( Ipn: 306-50408d ), ( Year: 2015 ), ( Manufacturer Warranty: 60 Day )

Review HONDA Engine Cylinder Head 1.5l Cr z fits CR 2012–2016

The **Honda 306-50408-D engine cylinder head** is a precision-engineered component designed exclusively for the **1.5-liter turbocharged (TURBO) 12-valve (12V) Honda CR-Z (2007 2010)** and its high-performance derivatives, including the **CR-Z Type S and limited-edition variants**. Crafted from high-grade **cast aluminum alloy (A319)**, this cylinder head is engineered to deliver exceptional durability, thermal efficiency, and performance under the demanding conditions of forced induction. The head features a **DOHC (Dual Overhead Camshaft) design**, housing two camshafts one for the intake valves and one for the exhaust each driving a set of **12 valves (6 intake, 6 exhaust)** via rocker arms. The intake valves are **0.450-inch (11.43 mm) in diameter**, while the exhaust valves measure **0.390-inch (9.91 mm)**, optimized for optimal airflow and combustion efficiency. The head incorporates **Honda s signature "VTEC" (Variable Valve Timing and Lift Electronic Control)** system, which dynamically adjusts valve timing and lift to enhance low-end torque and high-revving performance, particularly under turbocharged conditions. The **turbocharged variant** of this cylinder head is equipped with **reinforced valve seats and a high-flow exhaust port design**, allowing for greater scavenging and reduced backpressure to maximize power output. The **spark plug bores** are precision-machined to ensure a secure fit for NGK or Denso spark plugs, while the **oil passages** are strategically routed to minimize turbulence and ensure consistent lubrication to the camshafts and rocker arms. This cylinder head is also compatible with **Honda s high-performance fuel injection system**, including the **PGM-FI (Programmed Fuel Injection)** setup, which delivers precise fuel metering for optimal combustion. Whether used in a **stock CR-Z, a modified turbocharged project, or a high-revving track car**, this cylinder head is a critical component that ensures reliable operation, improved breathing, and the potential for significant power gains when paired with supporting modifications. Built to Honda s exacting standards, it is a **direct-fit replacement** for the original equipment (OEM) part, ensuring compatibility with the **1.5L turbocharged 12-valve engine** found in the CR-Z, making it an essential upgrade for enthusiasts seeking enhanced performance or restoration accuracy.

### **Pros and Cons of Buying a Honda 306-50408D Engine Cylinder Head (1.5L, 12-16 CR-Z)**

1. **High Performance Potential** The 1.5L K20 engine (used in the CR-Z) is a naturally aspirated inline-four with a high compression ratio (11.5:1), making it capable of significant power gains with modifications. A well-maintained cylinder head can support turbocharging, nitrous oxide, or forced induction upgrades.

2. **Aftermarket Support** The K20 engine is a popular choice among tuners, meaning there is a wide availability of aftermarket parts, including custom cylinder heads, intake manifolds, and performance camshafts. This makes upgrades more accessible and cost-effective.

3. **Lightweight and Compact Design** The 1.5L engine is relatively small and lightweight, which helps with weight distribution in the CR-Z s hybrid setup. A well-repaired or upgraded cylinder head can maintain this efficiency while improving performance.

4. **Potential for Hybrid Retuning** If you plan to keep the CR-Z s hybrid system, a properly rebuilt or upgraded cylinder head can help balance power output between the internal combustion engine (ICE) and electric motor, improving overall drivability and efficiency.

5. **Common Issues Are Well-Documented** Problems like valve spring failure, warped heads, or exhaust port erosion are known and can be addressed with proper maintenance or upgrades. This means you can make informed decisions about repairs or replacements.

6. **Resale Value for Modified CR-Zs** If you plan to keep the car as a project or daily driver, a well-maintained or upgraded cylinder head can enhance its appeal to enthusiasts, potentially increasing resale value in the modified market.

7. **Cost-Effective for Repairs** Compared to some other Honda engines, parts for the K20 are relatively affordable, especially if sourced from salvage yards or aftermarket suppliers. This makes repairs and upgrades more budget-friendly.

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- **Warping** (common due to overheating or poor cooling).

- **Exhaust port erosion** (from high-temperature exhaust gases).

- **Valve spring failure** (leading to valve float at high RPMs).

- **Leaking head gaskets** (if not properly torqued or if the block is warped).

Rebuilding or replacing a head may require machining or specialized parts, adding to costs.

- **Porting and polishing** (to improve airflow).

- **Valve job** (resurfacing seats and stems).

- **Camshaft replacement** (if worn or for performance gains).

- **Proper torque specifications** (to prevent warping or leaks).

This often requires mechanical skill or professional help, increasing expenses.

3. **Turbocharging Risks** While the K20 can handle forced induction, improper setup (e.g., insufficient cooling, wrong fueling, or weak internals) can lead to catastrophic failure, including head warping, piston damage, or turbo compressor failure. This requires careful planning and tuning.

4. **Hybrid System Compatibility** Modifying the ICE in a hybrid (like the CR-Z) can disrupt the balance between the electric motor and gasoline engine. Aggressive tuning may require recalibration of the hybrid system, which can be complex and costly if done improperly.

5. **Limited Stock Availability** New or OEM cylinder heads for the K20 engine may be difficult to find, especially for older models. This forces buyers to rely on aftermarket or used parts, which may vary in quality.

- **Internal cracks** (from overheating or poor casting).

- **Residual stress** (from previous warping or machining).

- **Corrosion or pitting** (in exhaust ports or combustion chambers).

These defects can compromise performance and longevity unless thoroughly inspected.

7. **Cost of Upgrades** While parts are affordable, upgrading a cylinder head to high-performance standards (e.g., porting, custom valves, or high-flow internals) can add up quickly. For example:

- **Porting and polishing** can cost $200 $500 per head.

- **High-performance camshafts** may require a full valve job.

- **Turbocharging** adds fueling, cooling, and support system costs.

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### **Recommendation**

The **Honda 306-50408D cylinder head (1.5L K20, 12-16 CR-Z)** is a capable and tunable component with significant potential for performance gains, but it comes with notable challenges. The engine s design allows for aggressive modifications, but its susceptibility to warping, exhaust port erosion, and valve issues means that proper maintenance, rebuilding, or upgrading is essential. Whether you re restoring a project car, preparing for forced induction, or simply ensuring reliability, the cylinder head is a critical and often costly component to address.

- **Inspect thoroughly** for warping, cracks, or exhaust port erosion. Use a straightedge to check for warpage, and look for signs of overheating or stress.

- **Prioritize OEM or high-quality aftermarket heads** if possible, as salvage parts may have unknown damage.

- **Consider a full valve job and porting** if planning to modify the engine, as this will improve airflow and longevity.

- **Machine the head professionally** if warped or worn, and ensure proper torque specs are followed during assembly.

- **Upgrade to high-flow internals** (e.g., larger valves, ported manifolds) if aiming for forced induction or high RPM performance.

- **Invest in a high-quality camshaft** (e.g., JE, Scat, or Honda Performance Parts) to match your power goals.

- **Start with a reliable base** a rebuilt or ported head is essential before adding a turbo or supercharger.

- **Upgrade cooling** (intercooler, radiator, oil cooler) to prevent overheating, which is the #1 killer of K20 heads.

- **Tune the engine properly** to avoid detonation, which can warp the head or damage pistons.

- **Consider a hybrid-specific tune** if keeping the CR-Z s electric motor, as aggressive ICE power may require recalibration.

- **Balance performance and reliability** while the K20 can handle power, excessive modifications may void warranties (if applicable) or reduce longevity.

- **Monitor for common issues** (e.g., valve float, head leaks) and address them promptly.

- **Document modifications** for future resale, as modified CR-Zs with well-maintained engines can hold value in the enthusiast market.

The **306-50408D cylinder head is a great choice for those willing to invest time and effort** into maintaining or upgrading it. It offers **excellent tunability** and **enthusiast appeal**, but it requires **careful handling** to avoid common failure points. If you re prepared for the work or have access to professional help, it can be a **cost-effective and rewarding** part of a CR-Z build. However, if you re looking for a **plug-and-play solution with minimal hassle**, you may want to consider a pre-built or heavily modified engine from a trusted supplier.

Details:

CR-Z 12-16 1.5L. Donor Vehicle - 2015 CR-Z. Stock Number - 2603. It is stored in doors and ready to be shipped.

Cylinder head. Warranty: All parts come with our standard 60 day warranty.

specifications cylinderheapar:

• for models: Cr
• for makes: Honda
• for years: 2012-2016
• model: Cr-z
• part type: Engine Cylinder Head
• conditions options: 4, 1.5
• genuine oem: Yes
• ipn: 306-50408d
• year: 2015
• manufacturer warranty: 60 Day

seller cylinderheapar:

• city: Sauk Centre, Minnesota
• rating: 99.7%
• # reviews: 29036

shipping cylinderheapar:

• service: UPS Ground
• cost: $0.00
• type: Fixed
• class: Standard
• carrier: UPS
• transit: 3-5 Days

payments cylinderheapar:

• other
• credit card: Visa
• wallet: Paypal

offer cylinderheapar:

• quantity: 1
• best offers: True
• availability: In Stock
• sold: 0
• options: Ship-to-home
• started: April 17, 2026

general cylinderheapar:

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

returns cylinderheapar:

• policy: Returns Accepted
• time: 60 Days
• paid by: Buyer

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