1992 Nissan 240sx Engine Specs

Alright, let's dive into the engine specs for the 1992 Nissan 240sx. This car, especially the ones from '89 to '94, enjoys a legendary status in the tuning and drifting community, and a big reason for that is its engine. In 1992, you're primarily looking at two engine options: the KA24E and the KA24DE. We'll break down each of these, covering their key technical details, so you know exactly what you're dealing with.

The KA24E: The SOHC Workhorse

The KA24E is a 2.4-liter (2389cc to be exact) inline four-cylinder engine featuring a Single Overhead Camshaft (SOHC) design. SOHC means it only has one camshaft in the cylinder head, which controls both the intake and exhaust valves. This makes it a simpler design compared to a DOHC engine, and generally translates to a slightly lower peak power output, but can offer good low-end torque.

Key Specs for the KA24E:

Displacement: 2.4 liters (2389 cc, 145.8 cu in)
Bore x Stroke: 89 mm x 96 mm (3.50 in x 3.78 in)
Compression Ratio: 8.6:1
Fuel System: Electronic Fuel Injection (EFI)
Horsepower (SAE Net): 140 hp @ 5600 rpm (approximately, may vary slightly based on model and year)
Torque (SAE Net): 152 lb-ft @ 4400 rpm (approximately)
Valve Train: SOHC, 12 valves (3 valves per cylinder - 2 intake, 1 exhaust)
Firing Order: 1-3-4-2

Let's unpack some of these. The bore refers to the diameter of the cylinder, and the stroke is the distance the piston travels within the cylinder. The bore and stroke measurements are crucial for calculating engine displacement. The compression ratio (8.6:1 in this case) is the ratio of the cylinder volume at its largest (when the piston is at the bottom of its stroke) to its smallest (when the piston is at the top of its stroke). A lower compression ratio, like the KA24E, generally allows the engine to run on lower octane fuel and is more tolerant of forced induction (turbocharging or supercharging) without requiring extensive modifications. However, it may also result in slightly lower overall efficiency compared to a higher compression engine.

The KA24E uses a distributor ignition system. This means a rotating distributor cap directs the high-voltage spark to the correct cylinder at the right time. It's a relatively reliable system, but often replaced with coil-on-plug setups in high performance applications for better spark control and reliability at higher RPMs.

One notable feature of the KA24E is its cast iron block. While heavier than an aluminum block, cast iron offers greater strength and durability, making it a good candidate for boosting power with forced induction.

The KA24DE: The DOHC Upgrade

The KA24DE is the more desirable of the two engines. It's also a 2.4-liter inline four-cylinder, but it features a Dual Overhead Camshaft (DOHC) design. This means it has two camshafts in the cylinder head: one for the intake valves and one for the exhaust valves. The DOHC design allows for more precise valve timing and control, resulting in improved airflow and, consequently, higher power output.

Key Specs for the KA24DE:

Displacement: 2.4 liters (2389 cc, 145.8 cu in)
Bore x Stroke: 89 mm x 96 mm (3.50 in x 3.78 in)
Compression Ratio: 9.5:1
Fuel System: Electronic Fuel Injection (EFI)
Horsepower (SAE Net): 155 hp @ 5600 rpm (approximately, may vary slightly based on model and year)
Torque (SAE Net): 160 lb-ft @ 4400 rpm (approximately)
Valve Train: DOHC, 16 valves (4 valves per cylinder - 2 intake, 2 exhaust)
Firing Order: 1-3-4-2

You'll notice that the bore and stroke are identical to the KA24E, meaning the displacement is the same. The crucial difference is the DOHC cylinder head and the higher compression ratio of 9.5:1. This increase in compression, along with the improved valve control, contributes to the KA24DE's higher horsepower and torque figures.

Like the KA24E, the KA24DE also uses a distributor ignition system, and features a cast iron block for enhanced durability. The 4 valves per cylinder design in the KA24DE allows for greater airflow into and out of the combustion chamber, further contributing to its increased power output.

The KA24DE uses a timing chain, which is generally more durable and requires less frequent replacement than a timing belt. However, timing chains can still stretch or wear over time, so it's important to inspect it during regular maintenance.

Comparing the KA24E and KA24DE: Which is Better?

The KA24DE is generally considered the better engine due to its higher power output and improved breathing capabilities. However, the KA24E is still a solid engine with good low-end torque and proven reliability. If you're primarily looking for a reliable daily driver, the KA24E is perfectly adequate. However, if you're planning on doing any performance modifications, the KA24DE is the clear choice.

"Think of the KA24E as the dependable workhorse, and the KA24DE as the slightly more refined and powerful version."

Common Issues and Maintenance:

Both the KA24E and KA24DE are known for their reliability, but they are not immune to issues, especially given their age. Here are some common problems and maintenance tips:

Timing Chain Issues: As mentioned earlier, the timing chain can stretch or wear over time, leading to timing issues. Listen for a rattling noise, especially at startup.
Distributor Problems: The distributor can fail, leading to misfires and poor performance. Consider upgrading to a coil-on-plug system for improved reliability.
Oil Leaks: Valve cover gaskets, oil pan gaskets, and rear main seals are common sources of oil leaks. Regular inspection and replacement are necessary.
Cooling System: The cooling system is crucial for preventing overheating. Ensure the radiator is clean, the thermostat is functioning properly, and the coolant is fresh.
Regular Maintenance: Oil changes, spark plug replacements, and air filter cleaning are essential for maintaining engine health.

Modifications and Upgrades:

The KA24E and KA24DE engines are popular platforms for modifications, ranging from simple bolt-ons to complete engine swaps. Here are some common upgrades:

Intake and Exhaust: Upgrading the intake and exhaust systems can improve airflow and increase horsepower.
ECU Tuning: Tuning the engine control unit (ECU) can optimize fuel and timing for increased performance.
Forced Induction: Turbocharging or supercharging can significantly increase power output, but requires careful planning and supporting modifications.
Cylinder Head Work: Porting and polishing the cylinder head can improve airflow and increase horsepower.
Engine Swaps: Some popular engine swaps include the SR20DET (a turbocharged 2.0-liter engine) and the LS series V8 engines.

When considering modifications, it's important to do your research and choose components that are compatible with your engine and your goals. Start with the basics, such as intake, exhaust, and ECU tuning, before moving on to more complex modifications like forced induction.

Important Note: If you're planning on making significant modifications to your engine, it's crucial to have it professionally tuned to ensure optimal performance and reliability. A poorly tuned engine can suffer from damage or reduced lifespan.

In conclusion, the 1992 Nissan 240sx offered two excellent engine options, the KA24E and KA24DE. While the KA24DE provides a performance edge, both engines are durable and capable of satisfying the needs of daily driving or providing a solid base for performance modifications. Remember to maintain your engine properly and research any modifications thoroughly to ensure a long and enjoyable ownership experience.