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The Mitsubishi 4G63 engine is a popular choice among performance enthusiasts, known for its robust design and tuning potential. One of the most effective ways to enhance its performance is by upgrading the cylinder head. This article will explore various modifications to the 4G63 head that can improve airflow and overall power output.
Understanding the 4G63 Cylinder Head
The 4G63 engine features a DOHC design with a 16-valve configuration. Its cylinder head plays a crucial role in the engine’s performance by controlling airflow into and out of the combustion chamber. By optimizing this component, you can significantly increase horsepower and torque.
Key Modifications for Improved Flow
- Porting and Polishing: This process involves reshaping the intake and exhaust ports to enhance airflow.
- Upgraded Valves: Larger valves can increase airflow, allowing for better engine breathing.
- High-Performance Valve Springs: These prevent valve float at high RPMs, ensuring optimal performance.
- Adjustable Cam Gears: These allow for precise tuning of valve timing for improved performance.
Porting and Polishing the Head
Porting and polishing is an essential modification for enhancing the 4G63 head. This technique improves the shape of the intake and exhaust ports, reducing turbulence and increasing airflow. A well-executed port job can lead to significant power gains.
Tools and Techniques
To port and polish the 4G63 head, you will need specific tools, including:
- Dremel tool or die grinder
- Porting bits
- Polishing compounds
- Measuring tools for consistency
Start by removing the head from the engine and cleaning it thoroughly. Carefully remove material from the ports, focusing on creating smooth transitions. After porting, polish the ports to a mirror finish to minimize friction and improve airflow.
Upgrading Valves
Replacing the stock valves with larger, high-performance valves is another effective way to increase airflow in the 4G63 head. Larger valves allow more air and fuel mixture into the combustion chamber, leading to better combustion and more power.
Choosing the Right Valves
When selecting valves, consider the following:
- Material: Stainless steel is commonly used for its durability and resistance to heat.
- Size: Opt for valves that are larger than stock but still fit within the head’s design.
- Weight: Lighter valves can improve responsiveness and reduce stress on the valvetrain.
Ensure that the valve seats are also machined to accommodate the new valves, providing a proper seal for optimal performance.
High-Performance Valve Springs
Upgrading to high-performance valve springs is crucial when increasing engine RPM or adding more aggressive camshafts. Stock springs may not be able to handle the increased demands, leading to valve float and performance loss.
Benefits of Upgraded Springs
High-performance valve springs offer several advantages:
- Improved stability at high RPMs
- Better throttle response
- Reduced risk of valve float
Adjustable Cam Gears
Installing adjustable cam gears allows for fine-tuning of the valve timing, which can lead to improved performance across the RPM range. This modification is especially beneficial for those looking to maximize power on the track or during spirited driving.
How to Adjust Cam Timing
To adjust cam timing, follow these steps:
- Install the adjustable cam gears according to the manufacturer’s instructions.
- Use a degree wheel to measure the current timing.
- Make incremental adjustments and test the engine’s performance after each change.
Conclusion
Upgrading the 4G63 cylinder head is a powerful way to enhance engine performance. By focusing on porting and polishing, upgrading valves, installing high-performance springs, and utilizing adjustable cam gears, enthusiasts can unlock the full potential of this iconic engine. These modifications not only improve airflow but also contribute to a more responsive and powerful driving experience.