240sx 5-speed Swap Parts List: Everything You Need For A Manual Conversion
Converting a 240SX from an automatic to a manual transmission – a 5-speed swap – is a popular modification, offering a more engaging driving experience and potentially improved fuel economy. However, successfully completing this conversion requires meticulous planning and a comprehensive understanding of the required parts. This guide provides a detailed breakdown of the components necessary for a seamless 5-speed swap, delving into the function and potential variations of each part.
The Foundation: The Transmission
At the heart of the swap lies the transmission itself. The most common choices are transmissions from other Nissan vehicles, primarily due to their relatively easy integration.
Identifying Suitable Transmissions
Several Nissan transmissions are compatible with the 240SX engine, but some are better suited than others. The KA24DE engine (found in the later 240SX models) and the SR20DET engine (from Silvia/180SX models, often imported) are the most common engines to pair with a manual transmission.
- KA24DE Transmission: This is the most straightforward option for KA24DE-equipped 240SX models. It's a direct bolt-on and requires minimal modification. It's generally considered strong enough for stock or mildly modified KA24DE engines.
- SR20DET Transmission: This transmission is significantly stronger than the KA24DE transmission and is a popular upgrade, especially for boosted KA24DE engines or when performing an SR20DET swap. However, it requires more modifications, including a different driveshaft and potentially a different transmission crossmember. The SR transmission commonly has two variants, the blacktop transmission and the redtop transmission, with slightly differing gear ratios.
Crucially, ensure the transmission is in good working order before installation. Inspect for leaks, smooth shifting action, and any signs of excessive wear. Consider rebuilding the transmission as preventative maintenance, especially if its history is unknown.
Connecting the Engine: The Clutch and Flywheel
The clutch and flywheel are essential for transmitting power from the engine to the transmission.
Flywheel Selection
The flywheel bolts to the engine's crankshaft and provides a surface for the clutch disc to grip. When choosing a flywheel, consider the following:
- Compatibility: The flywheel must be compatible with both the engine (KA24DE or SR20DET) and the transmission you've selected. KA and SR flywheels are generally not interchangeable without modification.
- Weight: Lighter flywheels improve engine response and acceleration but can make the car more difficult to drive smoothly at low speeds. Heavier flywheels provide smoother idling and easier launches but can reduce acceleration. A lightweight flywheel is recommended for performance applications, while a stock-weight flywheel is suitable for daily driving.
- Material: Flywheels are typically made from steel or aluminum. Steel flywheels are more durable and cost-effective, while aluminum flywheels are lighter but more expensive.
Clutch Selection
The clutch disc, pressure plate, and throw-out bearing work together to engage and disengage the engine from the transmission. When choosing a clutch, consider:
- Torque Capacity: The clutch must be able to handle the engine's torque output. If you plan to increase the engine's power, choose a clutch with a higher torque capacity than the stock clutch.
- Driving Style: Different clutch types are suited for different driving styles. Organic clutches provide smooth engagement and are suitable for daily driving. Ceramic clutches offer higher torque capacity but can be more aggressive and less forgiving.
- Clutch Kit: It's generally recommended to purchase a complete clutch kit, which includes the clutch disc, pressure plate, and throw-out bearing. This ensures proper compatibility and simplifies the installation process.
A new pilot bushing or bearing should always be installed in the crankshaft to support the transmission input shaft.
The Control Center: The Pedal Assembly
Converting to a manual transmission requires installing a clutch pedal assembly.
Obtaining a Clutch Pedal Assembly
The best option is to source a clutch pedal assembly from a manual 240SX. This ensures a direct bolt-in fit and proper functionality.
Master Cylinder and Slave Cylinder
The clutch pedal assembly actuates a master cylinder, which hydraulically engages the slave cylinder, which then moves the clutch fork. These parts must be matched and in good working condition. Check for leaks and smooth operation. Sometimes the master cylinder needs to be replaced due to age, and a braided line going from the master to the slave cylinder is an upgrade to improve clutch feel.
Clutch Lines
You'll need a clutch line to connect the master cylinder to the slave cylinder. You can use a factory line from a manual 240SX, or upgrade to a stainless steel braided line for improved durability and feel.
The Linkage: Shifter and Linkage
The shifter allows the driver to select gears in the transmission.
Shifter Assembly
You'll need a shifter assembly from a manual 240SX or a compatible Nissan vehicle. Aftermarket short shifters are also available, which reduce the throw distance between gears. When installing the shifter, use new shifter bushings to remove any slop and improve the shifting feel.
Shift Linkage
The shift linkage connects the shifter to the transmission. Ensure the linkage is in good condition and that all bushings are intact. Worn bushings can cause sloppy shifting.
Connecting to the Rear: The Driveshaft
The driveshaft transmits power from the transmission to the rear differential.
Driveshaft Length
The driveshaft length will depend on the transmission you're using. The driveshaft from an automatic 240SX is too short for a manual transmission. You'll need a driveshaft from a manual 240SX or a custom-made driveshaft. The SR20DET transmission typically requires a shorter driveshaft than the KA24DE transmission in a 240SX chassis.
Driveshaft Condition
Inspect the driveshaft for any signs of damage, such as dents or bends. Replace the U-joints if they are worn or damaged. It's generally a good idea to have the driveshaft balanced before installation to prevent vibrations.
Supporting the Transmission: The Transmission Mount
The transmission mount supports the transmission and isolates it from the chassis.
Transmission Crossmember
The transmission crossmember is typically different between automatic and manual transmissions. You'll need the crossmember for the corresponding manual transmission. Some aftermarket crossmembers offer adjustability, which can be useful for fine-tuning driveline angles.
Transmission Mount
Replace the transmission mount with a new one to ensure proper support and reduce vibrations. Stiffer aftermarket mounts are available, but they can transmit more vibrations into the cabin.
Miscellaneous Components
Several other components are required for a complete 5-speed swap.
- ECU/Wiring: The ECU (Engine Control Unit) may need to be modified or replaced to properly control the engine with a manual transmission. If using the stock ECU, you may need to bypass the neutral safety switch. For SR20DET swaps, an SR20DET ECU is generally required.
- Neutral Safety Switch Bypass: Automatic transmissions have a neutral safety switch that prevents the engine from starting unless the transmission is in park or neutral. You'll need to bypass this switch to allow the engine to start with the manual transmission.
- Reverse Light Switch: The manual transmission has a reverse light switch that activates the reverse lights when the transmission is in reverse. You'll need to wire this switch to the reverse lights.
- Speedometer Cable: The speedometer cable connects to the transmission and provides speed information to the instrument cluster. Ensure the speedometer cable is compatible with the transmission.
- Fluids: You'll need to refill the transmission with the appropriate type of gear oil.
- Bolts and Hardware: Ensure you have all the necessary bolts and hardware for installing the transmission, clutch, and other components. It's a good idea to purchase a bolt kit specifically designed for a 240SX 5-speed swap.
Conclusion
Performing a 5-speed swap on a 240SX is a significant undertaking, but with careful planning and the right parts, it can be a rewarding experience. This comprehensive parts list provides a solid foundation for a successful conversion. Remember to research thoroughly, source quality parts, and consult with experienced mechanics if needed. By understanding the function of each component, you can ensure a smooth and reliable manual transmission conversion for your 240SX.