Nissan 240SX – KA24E Engine Basics

KA24E is a 2.4-liter inline-four engine produced by Nissan. It was used in a variety of Nissan vehicles, including the 240SX, Pathfinder, and Pickup truck, among others. The “KA” in the engine code stands for “K-series engine, Athena” and the “E” stands for Electronic Fuel Injection (EFI).

Nissan 240SX models made before February of 1989 utilized the KA24E engine. This engine has a 9.1:1 compression ratio, outputting approximately 150 hp. After February of 1989, however, the compression ratio was reduced to 8.6:1 causing the KA24E to produce the advertised 140 hp.

The KA24E engine uses Sequential Electronic Fuel Injection (SEFI). The ECM controls each injector individually, releasing fuel into each cylinder on its intake stroke.

The Nissan KA24E is a reliable engine that can withstand substantial power increases on stock internals. This is due to the use of forged connecting rods and an internally balanced one-piece cast crankshaft.

KA24E Specifications

Displacement2.4 L
TypeSOHC Inline 4-cylinder
3 valves per cylinder
MaterialsCast Iron Block
Cast Aluminum Heads
Cast Aluminum Intake Manifold
Bore x Stroke89.0 mm x 96.0 mm
Compression Ratio8.6:1 (9.1:1 for early 1989 240SX)
Power140 hp @ 5600 RPM
Torque152 lb. ft. @ 4400 RPM
Redline6500 RPM

KA24E vs KA24DE

Engine type2.4-liter inline-four2.4-liter inline-four
Power output140 horsepower and 152 lb-ft of torque155-190 horsepower and 160-175 lb-ft of torque (varies by year and model)
ValvetrainSOHC (single overhead camshaft)DOHC (dual overhead camshaft)
Valve count12 valves (4 per cylinder)16 valves (4 per cylinder)
Fuel systemElectronic Fuel Injection (EFI)Electronic Fuel Injection (EFI)
Cylinder headAluminumAluminum
Block materialCast ironCast iron
Timing chainSingle-rowDuplex
Redline~6,500 RPM~7,500 RPM
AftermarketLarge aftermarket support for performance upgradesLarge aftermarket support for performance upgrades
KA24E Valvetrain

The KA24DE is an updated version of the KA24E, with improvements such as a dual overhead camshaft (DOHC) valvetrain and variable valve timing (VVT). It was produced from 1991 to 2008 and was used in a variety of Nissan vehicles, including the 240SX, Altima, and Frontier, among others. While both engines share the same displacement and basic design, the KA24DE produced more power and had better performance potential due to its DOHC valvetrain and other improvements.

The KA24E was produced from 1988 to 1997 and was a popular engine choice among enthusiasts due to its high-revving nature and reliability. It had an iron block and an aluminum head, with a single overhead camshaft (SOHC) and 12 valves. The engine produced around 135 horsepower and 154 lb-ft of torque in its stock form.

The KA24E engine was also popular for its potential for modifications and upgrades, and many enthusiasts have used it as a base for high-performance builds. The engine’s aftermarket support is vast, with many companies offering performance parts, such as camshafts, intake manifolds, exhaust systems, and turbo kits, among others.