Analysis Of Oem Vs. Aftermarket Engine Mounts For The Nissan 240sx

Alright, let's talk engine mounts. Specifically, engine mounts for the Nissan 240SX (S13/S14 chassis). You've probably seen the debates raging online: OEM versus aftermarket. Which is better? The answer, as always, is: it depends. It depends on your application, your budget, and your tolerance for increased NVH (Noise, Vibration, and Harshness). This article will break down the key differences, pros, and cons of both OEM and aftermarket engine mounts for the 240SX, arming you with the knowledge to make the right choice for your ride.

Understanding Engine Mount Function

Before diving into the specifics, let's quickly recap the purpose of engine mounts. Engine mounts are the crucial link between your engine and the chassis of your car. Their primary functions are:

Isolating Vibrations: Engines, especially high-performance ones, generate significant vibrations during operation. Engine mounts, typically made with a damping material like rubber or polyurethane, absorb these vibrations, preventing them from being transmitted directly to the car's frame and into the cabin. This is crucial for driving comfort.
Securing the Engine: The engine is a heavy component that needs to be securely held in place. Engine mounts prevent excessive engine movement, especially during hard acceleration, braking, and cornering. Excessive movement can damage surrounding components like the radiator hoses, exhaust manifold, and wiring harness.
Maintaining Proper Drivetrain Alignment: Engine mounts play a role in maintaining the correct alignment of the engine and transmission. This alignment is crucial for smooth power transfer and prevents premature wear on drivetrain components.

OEM Engine Mounts: The Original Design

OEM (Original Equipment Manufacturer) engine mounts are designed and manufactured by Nissan (or a supplier working directly with Nissan) to meet specific performance and comfort criteria. They are typically made of rubber, which provides excellent vibration damping.

Pros of OEM Engine Mounts:

Superior Vibration Damping: Rubber is inherently excellent at absorbing vibrations. OEM mounts excel at minimizing NVH, providing a smooth and comfortable ride. This is arguably their biggest advantage.
Cost-Effective (Initially): While prices can vary, OEM mounts are often initially cheaper than many high-end aftermarket options, especially if purchased from a discount online retailer.
Direct Fitment: OEM mounts are guaranteed to fit perfectly. No modifications are required. This makes installation straightforward for even novice mechanics.
Designed for Longevity (Under Normal Conditions): OEM mounts are designed to last for many years under normal driving conditions.

Cons of OEM Engine Mounts:

Susceptibility to Degradation: Rubber degrades over time, especially when exposed to heat, oil, and other harsh conditions. OEM mounts can become brittle and cracked, losing their ability to effectively dampen vibrations and secure the engine.
Softness Under High Performance: The softness of the rubber allows for significant engine movement, especially under hard acceleration or during spirited driving. This movement can lead to a loss of power transfer and potential damage to other components. This is the main reason why many performance-oriented 240SX owners ditch the OEM mounts.
Not Ideal for Increased Horsepower: If you've significantly increased the horsepower of your 240SX (e.g., through turbocharging or engine swaps), OEM mounts may not be strong enough to handle the increased torque.

Aftermarket Engine Mounts: The Performance Upgrade

Aftermarket engine mounts are designed and manufactured by companies other than Nissan. They typically use polyurethane (poly) or a combination of polyurethane and metal. Polyurethane is a stiffer and more durable material than rubber.

Pros of Aftermarket Engine Mounts:

Reduced Engine Movement: The stiffer material significantly reduces engine movement, providing better power transfer to the wheels and preventing potential damage to surrounding components. This is particularly important for modified 240SXs.
Increased Durability: Polyurethane is much more resistant to degradation from heat, oil, and other harsh conditions compared to rubber. Aftermarket mounts generally last longer, especially in high-performance applications.
Improved Handling (Indirectly): By reducing engine movement, aftermarket mounts can improve the car's overall handling feel, particularly during cornering.
Available in Different Durometers: Aftermarket mounts often come in different durometers (hardness ratings). This allows you to fine-tune the level of stiffness and NVH to your liking. Softer poly mounts offer a better compromise between performance and comfort, while stiffer mounts are ideal for track use.

Cons of Aftermarket Engine Mounts:

Increased NVH: The biggest drawback of aftermarket mounts is the increased NVH. Because they are stiffer, they transmit more vibrations into the cabin. This can lead to a less comfortable ride, especially on long trips. The amount of NVH increase will depend on the durometer of the polyurethane used.
Higher Cost: Aftermarket mounts generally cost more than OEM mounts.
Potential Fitment Issues: While reputable brands design their mounts to fit correctly, some cheaper aftermarket options may have fitment issues, requiring modifications for proper installation. Always research the brand and read reviews before purchasing.
Polyurethane Wear: While more durable than rubber, polyurethane can still wear out over time, especially if subjected to extreme heat or stress. Some cheaper polyurethane compounds can also crack or crumble more easily.
Greasing/Lubrication: Some polyurethane mounts require periodic greasing to prevent squeaking.

Durometer: Understanding Polyurethane Hardness

Durometer is a measure of the hardness of a material. In the context of engine mounts, it refers to the hardness of the polyurethane. Durometer is measured on a Shore scale, typically Shore A. The higher the Shore A number, the harder the material.

Softer Poly Mounts (e.g., 60A-70A): These mounts offer a good compromise between performance and comfort. They will reduce engine movement compared to OEM mounts but will not transmit as much vibration into the cabin as stiffer mounts. A good choice for street cars that see occasional track use.
Medium Poly Mounts (e.g., 70A-80A): These mounts offer a noticeable improvement in performance and reduced engine movement. NVH will be more noticeable. Suitable for street/track cars or cars with significant power upgrades.
Stiffer Poly Mounts (e.g., 80A-90A+): These mounts offer the maximum reduction in engine movement and the best possible power transfer. NVH will be significantly increased. Primarily for track-only cars or cars built for extreme performance. Expect a rougher ride.

Choosing the Right Mounts for Your 240SX

So, which mounts are right for your 240SX? Consider the following factors:

Your Driving Style: Do you primarily use your 240SX for daily driving, or do you frequent the track? If you're a daily driver, OEM or softer poly mounts are likely the best choice. If you're a track enthusiast, stiffer poly mounts may be preferable.
Your Power Level: If you've significantly increased the horsepower of your 240SX, aftermarket mounts are highly recommended. OEM mounts may not be strong enough to handle the increased torque.
Your Tolerance for NVH: Be honest with yourself about how much NVH you can tolerate. If you're sensitive to vibrations and noise, stick with OEM or softer poly mounts. If you're willing to sacrifice some comfort for improved performance, consider stiffer poly mounts.
Your Budget: Factor in the cost of the mounts themselves, as well as any potential labor costs if you're not installing them yourself.

Installation Considerations

Installing engine mounts is a relatively straightforward process, but it does require some basic mechanical skills and tools. Always consult a repair manual or online tutorial specific to your 240SX chassis. Key steps include:

Safety First: Disconnect the battery and use jack stands to safely support the car.
Supporting the Engine: Use an engine support bar or a jack with a block of wood to support the engine from above. Do not rely solely on the engine mounts to support the engine's weight.
Loosening and Removing the Old Mounts: Carefully loosen and remove the bolts securing the old engine mounts.
Installing the New Mounts: Install the new engine mounts, ensuring they are properly aligned. Torque the bolts to the manufacturer's specifications.
Lowering the Engine: Slowly lower the engine onto the new mounts.
Final Check: Double-check all bolts and connections before starting the engine.

Important Notes:

Always replace engine mounts in pairs (both left and right).
Consider replacing the transmission mount at the same time, as it's also subject to wear and tear.
Some aftermarket mounts may require greasing before installation.

Conclusion

Ultimately, the best engine mounts for your Nissan 240SX depend on your individual needs and preferences. OEM mounts offer excellent vibration damping and a comfortable ride, but they may not be suitable for high-performance applications. Aftermarket mounts provide improved performance and durability, but they come at the cost of increased NVH. By carefully considering your driving style, power level, and tolerance for NVH, you can choose the mounts that are right for you and your 240SX.