Why the KA24DE Deserves a Performance Camshaft Upgrade

The Nissan KA24DE engine has earned a loyal following among enthusiasts for its cast-iron block, closed-deck design, and surprising torque output. Found in the S13 and S14 240SX as well as the D21 Hardbody and Altima, this 2.4-liter inline-four is known for durability. However, the factory camshaft was designed with fuel economy and emissions compliance in mind, leaving significant power on the table. A camshaft swap is one of the most effective single modifications you can make to unlock the KA24DE's true potential, and the JWT Super 20 cam from Jim Wolf Technology has become a benchmark upgrade in the community.

This article provides a thorough breakdown of the JWT Super 20 camshaft, including its design specs, real-world performance gains, a detailed installation walkthrough, supporting modifications you should consider, and a complete cost analysis to help you budget properly. Whether you are a seasoned DIY mechanic or planning to have a shop handle the work, this guide will give you everything you need to make an informed decision.

Understanding the JWT Super 20 Camshaft: Specs and Design Philosophy

Jim Wolf Technology has been engineering high-performance Nissan components for decades, and the Super 20 cam is one of their most popular offerings for the KA24DE. The "Super 20" designation refers to a specific grind profile that provides substantially more duration and lift than the stock cam while remaining compatible with factory valvetrain components under most conditions.

Camshaft Specifications

The JWT Super 20 cam offers approximately 264 degrees of duration at .050-inch lift on both intake and exhaust, with a net valve lift in the range of .467-inch to .480-inch depending on the exact grind version. Compare this to the stock KA24DE cam, which has roughly 238 degrees of duration and .375-inch of lift. The increased duration allows more air and fuel to enter the cylinder at higher RPM, while the additional lift improves flow through the intake and exhaust ports. These numbers place the Super 20 firmly in the "mild street performance" category, making it suitable for daily-driven cars that also see track use.

What Makes This Cam Different from Others on the Market

Unlike more aggressive offerings such as the JWT Super 24 or custom ground units from companies like Kelford or Brian Crower, the Super 20 is designed to work with the factory valve springs at stock redline RPM levels. This is a critical advantage for budget-conscious builders because it eliminates the need for immediate valvetrain upgrades. The cam also retains reasonable idle quality, though you will notice a mild lope that many enthusiasts find appealing. Power delivery remains strong in the mid-range and pulls hard to 6500 RPM, making it an excellent match for a naturally aspirated street setup or a mild turbo build.

Real Performance Gains: What to Expect from the JWT Super 20

Claims of horsepower gains are easy to find, but real-world data from dyno-tested vehicles tells a more nuanced story. When installed on an otherwise stock KA24DE with a factory intake manifold, exhaust manifold, and ECU, the JWT Super 20 cam typically adds between 15 and 25 wheel horsepower, with peak gains occurring around 5500 to 6000 RPM. Torque output in the mid-range often improves by 10 to 15 lb-ft, though you may lose a small amount of low-end torque below 2500 RPM compared to the stock cam.

Supporting Modifications That Multiply Gains

To extract the maximum benefit from the Super 20 cam, consider pairing it with these complementary upgrades:

  • Header or exhaust manifold upgrade: A quality 4-1 or 4-2-1 header reduces exhaust restriction and allows the cam's increased exhaust duration to work effectively. Gains of 5 to 10 additional horsepower are common.
  • Cold air intake or short ram intake: The cam moves more air, so providing a less restrictive intake path helps. Expect a modest 3 to 5 horsepower improvement on top of the cam gain.
  • Tuning with a programmable ECU or ROM tune: This is the single most important supporting mod. The factory ECU is calibrated for the stock cam's timing and fuel requirements. Without tuning, you leave a significant amount of power on the table. A custom tune can recover low-end torque lost to the cam overlap and optimize the air-fuel ratio across the RPM band. Enthusiasts report an additional 10 to 15 horsepower from tuning alone after a cam swap.
  • Upgraded valve springs (optional but recommended for high-RPM use): If you plan to rev beyond 6500 RPM regularly, aftermarket valve springs from companies like Supertech or Ferrea provide necessary insurance against valve float.

Dyno-Proven Example: A Real-World Build

A well-documented example from the Nissan enthusiast community involved a 1991 240SX with a stock KA24DE, a JWT Super 20 cam, an OBX header, a cone filter intake, and a tuned ECU using Nistune. On a Dynojet dynamometer, this combination produced 168 wheel horsepower and 158 lb-ft of torque. For reference, a stock KA24DE typically puts down 125 to 130 wheel horsepower. That represents a gain of roughly 38 to 43 horsepower at the wheels, which is transformative for a car that weighs around 2700 pounds. The owner reported a noticeable improvement in throttle response and an unmistakable exhaust note that made the car feel significantly more alive.

For more detailed dyno graphs and community discussions, visit the NICOclub forums, which maintain extensive archives of KA24DE performance data.

Pre-Installation Preparation: What You Need to Know Before You Start

Installing a camshaft is not a beginner-level job, but it is manageable for a DIY enthusiast with intermediate mechanical experience. Before you pull the valve cover, consider these preparation steps to avoid frustrating setbacks.

Assess Your Engine's Condition

If your KA24DE has high mileage or shows signs of sludge buildup, a cam swap is an excellent opportunity to address underlying maintenance issues. Inspect the timing chain guides, tensioner, and chain for wear. A stretched timing chain or worn plastic guides can cause timing inaccuracies that will compromise performance. Many builders choose to replace the timing chain kit at this stage, adding roughly $80 to $150 to the project cost but providing peace of mind.

Gather the Correct Fluids and Gaskets

You will need a new valve cover gasket, spark plug tube seals, and camshaft seal. Using genuine Nissan or high-quality aftermarket gaskets is strongly recommended because cheap gaskets often leak within a few thousand miles. Have fresh engine oil and a new oil filter on hand. The KA24DE requires approximately 4.5 quarts of oil with a filter change. For break-in purposes, many builders use a conventional 10W-30 oil or a dedicated break-in oil containing high levels of zinc and phosphorus to protect the cam lobes during initial operation.

Set Up Your Workspace

Working on the timing chain area of a KA24DE requires patience and attention to detail. Make sure you have adequate lighting, a clean work surface for storing removed parts, and a factory service manual or a reliable online guide. The JWT official website provides basic installation notes, but the factory Nissan service manual for the KA24DE is an essential reference for torque specifications and alignment procedures.

Step-by-Step Installation Guide

This procedure assumes the engine is out of the car or you have good access to the front of the engine. If the engine is in the car, you will need to remove the radiator fan, radiator shroud, and possibly the radiator itself to gain clearance.

Tools Required

  • Metric socket set with extensions: 10mm, 12mm, 14mm, 17mm, 19mm
  • Torque wrench capable of reading in inch-pounds and foot-pounds
  • Timing chain wedge or tensioner compressor tool
  • Camshaft socket (typically 24mm or 27mm depending on the year)
  • Pry bar medium size
  • Feeler gauge set for checking valve clearance if shimming is needed
  • RTV silicone gasket maker
  • Thread locker medium strength
  • Shop towels and brake cleaner

Disassembly and Removal

  1. Disconnect the battery: Disconnect the negative terminal to prevent accidental starter engagement or short circuits while working near the engine.
  2. Remove the intake manifold and throttle body: The intake manifold must come off to access the camshaft caps on the KA24DE. Label all vacuum lines and electrical connections as you remove them. This step is time-consuming but necessary.
  3. Drain the engine oil and remove the valve cover: Draining the oil before removing the valve cover prevents contamination from falling debris. Remove all spark plug wires or coil packs and set them aside.
  4. Rotate the engine to top dead center: Use a socket on the crankshaft pulley bolt to rotate the engine until the timing marks on the crankshaft sprocket and camshaft sprockets align. The engine should be at TDC on the compression stroke for cylinder 1. Verify this by checking that the distributor rotor points to the cylinder 1 plug wire position.
  5. Remove the timing chain tensioner: The tensioner is located on the driver side of the engine near the front. Compress the tensioner using a suitable tool or a C-clamp and lock it in place with a pin or small drill bit. Remove the two 12mm bolts securing the tensioner and slide it out.
  6. Remove the camshaft sprockets: Hold the camshaft with a wrench on the hex portion provided on the cam between lobes or use a camshaft holding tool. Remove the sprocket bolts. These bolts are typically torqued to 65-75 ft-lbs and may require a breaker bar. Lift the sprockets off the camshafts and carefully support the timing chain so it does not fall into the oil pan.
  7. Unbolt the camshaft bearing caps: The camshaft caps are numbered and must be reinstalled in their original positions and orientations. Loosen the cap bolts gradually in a crisscross pattern to prevent bending the camshaft. Remove the caps and lift out the stock camshaft.

Installation of the JWT Super 20 Cam

  1. Apply assembly lube: Before installing the new cam, liberally apply camshaft assembly lube or a high-zinc grease to all journal surfaces and the cam lobes. This step is critical for preventing galling during the first few seconds of engine operation.
  2. Place the cam into position: Lower the JWT Super 20 cam into the bearing saddles. Orient the cam so that the camshaft sprocket alignment dowel pin is in the correct position relative to the timing chain. The dowel pin should be at approximately the 12 o'clock position when the engine is at TDC.
  3. Install the bearing caps: Reinstall the camshaft caps in their numbered order and orientation. Apply a light coating of engine oil to the cap threads. Torque the cap bolts in several stages using a crisscross pattern. The final torque specification is typically 12 to 15 ft-lbs for the KA24DE cam caps. Do not overtighten, as the aluminum caps can strip easily.
  4. Install the camshaft sprockets: Fit the sprockets onto the camshafts, ensuring the timing chain is properly meshed with both cam sprockets and the crankshaft sprocket. Install the sprocket bolts and torque them to the factory specification of 65-75 ft-lbs. Use thread locker on these bolts.
  5. Install the timing chain tensioner: Remove the locking pin or tool from the tensioner and install it into the engine block. Tighten the tensioner bolts to 12-15 ft-lbs. Release the tensioner plunger by turning the crankshaft two full rotations clockwise. Verify that all timing marks still align perfectly. If they do not, repeat the alignment process.
  6. Check valve clearance: The KA24DE uses mechanical bucket tappets that require shimming to achieve correct valve clearance. The stock clearance specification is 0.010-0.013 inches for intake and 0.012-0.015 inches for exhaust. Because the JWT Super 20 cam has a different base circle, you may need to install different thickness shims to achieve these clearances. If you are not comfortable doing this yourself, have a machine shop measure and order the correct shims.

Reassembly and First Start

  1. Clean the valve cover surface and install a new valve cover gasket. Apply a small bead of RTV at the corners where the cam cap half-moons meet the cylinder head.
  2. Reinstall the intake manifold and throttle body using new gaskets.
  3. Fill the engine with fresh oil and install a new filter.
  4. Reconnect the battery and prime the oil system by cranking the engine with the fuel pump fuse removed or the injectors disconnected. Crank for 10 seconds, pause for 30 seconds, and repeat two or three times. This ensures oil reaches all cam journals before the engine fires.
  5. Start the engine and listen for abnormal noises. A mild ticking from the valvetrain is normal until the hydraulic lifters fill with oil. If you hear severe knocking or rattling, shut the engine down immediately and investigate.
  6. Check for oil leaks around the valve cover and cam seals.
  7. Allow the engine to reach operating temperature and hold a steady idle for about 15 minutes to properly break in the cam lobes.

Tuning Requirements: Making the Most of Your Cam

As mentioned earlier, tuning is essential to maximize the JWT Super 20 cam. The factory ECU uses a fixed timing map and fuel map that do not account for the cam's increased airflow and overlap. Driving the car without tuning will result in a check engine light, poor throttle response, rich or lean air-fuel ratios, and reduced power gains. Fortunately, several tuning options exist for the KA24DE.

ECU Tuning Options

  • Nistune: This is the most popular option for DIY enthusiasts. Nistune is a daughterboard that replaces the factory ECU's ROM chip and allows real-time tuning via a laptop. A preloaded base map for the Super 20 cam is often available from the tuner community. Expect to pay roughly $300 to $400 for the Nistune board and a license.
  • Rom tune via socketed ECU: Some companies offer mail-order ROM tunes where you send in your ECU, and they burn a custom chip for your specific setup. This is a plug-and-play solution that costs around $200 to $300 but offers no adjustability if you make further modifications.
  • Standalone ECU: Units from Haltech, AEM, or Megasquirt offer full control and are ideal if you plan to add forced induction later. Cost starts at around $800 for entry-level systems and climbs quickly.

If you are not confident in tuning yourself, professional dyno tuning typically costs $400 to $600 and is well worth the investment. A reputable tuner will optimize your timing and fuel maps for maximum power and drivability while ensuring the engine runs safely. Check resources like the KA-T.org community forums for tuner recommendations in your area.

Complete Cost Breakdown: DIY vs. Professional Installation

Below is a comprehensive cost breakdown that covers the camshaft, supporting parts, tools, and labor. Prices reflect current market averages in the United States as of early 2025 and may vary based on location and vendor.

Component Costs

Item Estimated Cost
JWT Super 20 Camshaft $550 - $700
Valve cover gasket set (including spark plug seals) $25 - $50
Camshaft seals (front) $15 - $30
Intake manifold gasket $10 - $20
Timing chain tensioner gasket $5 - $10
Engine oil and filter $30 - $50
Assembly lube and RTV $10 - $20
Valve shim set (if needed) $40 - $80
Timing chain kit (optional but recommended) $80 - $150
Camshaft sprocket bolts (if replacing) $10 - $20

Tool Costs (if not already owned)

Tool Estimated Cost
Timing chain tensioner compressor tool $20 - $40
Camshaft holding tool or adjustable spanner $15 - $35
Torque wrench (1/2-inch drive) $40 - $80
Feeler gauge set $10 - $15
Additional hand tools if not owned $50 - $150

Labor Costs

  • DIY installation: $0 for labor, but expect to invest 8 to 14 hours of your own time, especially if this is your first cam swap on a KA24DE.
  • Professional installation by a shop: $400 to $800 depending on the shop's hourly rate (typically $80 to $150 per hour). Some shops charge a flat rate for cam swaps, so call ahead for a quote.
  • Tuning by a professional: $400 to $600 on a dyno, or $200 to $350 for a street tune.

Total Cost Scenarios

Scenario 1: Budget DIY build with existing tools and no tuning – Cam plus gaskets and fluids: approximately $650 to $900. You will leave power on the table without tuning, but the car will run.

Scenario 2: Complete DIY build with tool purchase and professional tuning – Cam, gaskets, fluids, timing chain kit, tools, and tuning: approximately $1,200 to $1,600. This is the recommended approach for balanced cost and performance.

Scenario 3: Full professional installation and tuning – Everything including parts, labor, and dyno tuning: approximately $1,800 to $2,500. You pay for convenience and professional expertise.

Common Mistakes and How to Avoid Them

Even experienced mechanics can run into trouble with a KA24DE cam swap. Here are the most frequent pitfalls and tips to avoid them:

Mistiming the Engine

The KA24DE uses a timing chain, and getting the cam timing off by even one tooth will cause poor performance and may lead to piston-to-valve contact if the cam has high lift. Always verify timing marks after rotating the engine by hand two full revolutions. If the marks do not align perfectly, restart the chain installation process.

Forgetting to Replace the Timing Chain Tensioner

The plastic guides on the stock tensioner are known to become brittle with age and heat cycles. A broken guide can allow the timing chain to slap against the timing cover or jump teeth, destroying your engine. Replacing the tensioner and guides while you have the engine apart is cheap insurance.

Incorrect Valve Clearance

Installing the cam without checking valve clearance can lead to noisy valvetrain, reduced power, and in extreme cases, bent valves. Do not skip this step. If you do not have the correct shims, order them before reinstalling the valve cover.

Overtightening Cam Cap Bolts

The cam caps are aluminum and the threads strip easily. Use a torque wrench and follow the specified torque value. If you strip a cam cap bolt hole, you will need to helicoil the thread or replace the cylinder head.

Is the JWT Super 20 Cam Right for Your Build?

The JWT Super 20 cam is an excellent choice for anyone seeking a noticeable power increase from their KA24DE without sacrificing daily drivability. It works well with naturally aspirated setups, turbocharged builds running moderate boost (up to about 12 psi), and even nitrous applications. The cam's compatibility with stock valve springs and the factory ECU (with tuning) makes it one of the most accessible performance upgrades for the platform.

If your goal is a high-horsepower turbo build exceeding 350 wheel horsepower, you may benefit from a more aggressive cam profile such as the JWT Super 24 or a custom grind. However, for the vast majority of street-driven KA24DEs, the Super 20 delivers the best balance of power, drivability, and cost. With careful installation and proper tuning, this cam can transform the character of your 240SX, Hardbody, or Altima, providing a driving experience that lives up to the engine's legendary reliability.

For additional technical resources and community advice, the Zilvia.net forums remain one of the most active hubs for KA24DE and 240SX discussion.