Introduction: Why Upgrade to a B16A2 Camshaft?

The B16A2 engine, found in the 1999–2000 Honda Civic Si and other models, is a high-revving 1.6L DOHC VTEC powerplant beloved by enthusiasts. While it produces a healthy 160 hp from the factory, a camshaft upgrade is one of the most effective bolt-on modifications for unlocking additional horsepower. Swapping in a performance B16A2 camshaft — whether an OEM replacement from a higher-spec variant (like the B16B CTR cam) or an aftermarket profile — can deliver a genuine 15–20 hp gain at the wheels when paired with proper tuning. This guide provides a complete step-by-step installation process, covering tools, safety precautions, critical torque values, and post-installation considerations. Follow these instructions carefully to achieve a reliable, power-boosting upgrade.

Tools and Materials Needed

Having the right equipment saves time and prevents damage to engine components. Below is a comprehensive list:

Essential Hand Tools

  • Metric socket set (8, 10, 12, 14, 17 mm) with extensions
  • Torque wrench (ft-lb and in-lb ranges)
  • Camshaft sprocket holder tool (or chain wrench)
  • Timing belt tensioner tool (or suitable pin/wrench)
  • Camshaft installation tool (to avoid lobe damage)
  • Flathead screwdrivers and pry bars (plastic trim tools recommended)
  • Dental pick or seal removal tool

New Hardware & Consumables

  • B16A2 camshaft (OEM or aftermarket, e.g., Skunk2 Pro Series, Bisimoto, or CTR)
  • Camshaft seal kit (includes front and rear cam seals)
  • Valve cover gasket (complete grommet set recommended)
  • Timing belt (replace if old or worn; HUL-9989 or equivalent)
  • Timing belt tensioner and spring
  • High-temp engine oil (5W-30 or 10W-40 for assembly lube)
  • RTV silicone gasket maker (for corner seals)
  • Brake cleaner or degreaser
  • Shop rags and gloves

Service Literature & Reference

Preparation Before Installation

Begin with a clean, well-lit workspace. Park the vehicle on a level surface, engage the parking brake, and let the engine cool completely (overnight if possible). A cool engine prevents burns and ensures thermal contraction makes component removal easier.

Safety Precautions

  • Disconnect the negative battery terminal to eliminate electrical shorts, accidental starter engagement, or damage to the ECU.
  • Remove the key from the ignition and keep it in your pocket.
  • Use jack stands if you need to access the lower portion of the engine (though cam swap is strictly an upper-engine job).
  • Work in a ventilated area to avoid inhaling solvent fumes.

Engine Positioning: Set to Top Dead Center (TDC)

Before disassembly, manually rotate the crankshaft clockwise (using a 17 mm socket on the crank pulley bolt) until the No. 1 cylinder is at TDC on the compression stroke. Confirm alignment: the camshaft sprocket’s UP mark should be at 12 o’clock, and the crankshaft pulley mark should align with the timing cover pointer. This ensures the valves are fully closed and the VTEC pins are in a safe position for cam removal.

Do not skip this step. Installing a camshaft with the engine out of time can bend valves instantly when the timing belt is re-tensioned.

Step-by-Step Camshaft Installation

Step 1: Remove the Engine Cover and Accessories

Using a 10 mm socket, remove the upper engine cover (if equipped). Then remove the intake resonator, bracket, and any vacuum hoses that obstruct access to the valve cover. Label connectors with tape if necessary. For USDM Civic Si 1999–2000, also remove the secondary air injection components if present.

Step 2: Remove the Valve Cover

Disconnect all spark plug wires (or coils) and move them aside. Unbolt the valve cover in a crisscross pattern (12 bolts for most B-series). Lift the cover gently; if it sticks, use a plastic pry bar at the corners — do not force the cover. Inspect the condition of the old gasket and grommets; they will be replaced.

Stuff clean shop rags into the openings around the timing chain tunnel and spark plug tubes to prevent debris from falling into the oil pan.

Step 3: Remove the Timing Belt and Cam Sprocket

With the engine at TDC and the timing belt exposed, loosen the tensioner bolt (14 mm) and compress the tensioner spring to relieve belt tension. Slide the belt off the camshaft sprocket. Do not rotate the crankshaft or camshaft independently once the belt is off.

  • Use the cam holder tool to keep the sprocket stationary while removing the 17 mm center bolt. This bolt is usually torqued to 59 ft-lb; a breaker bar may be needed.
  • Remove the sprocket and set it aside. Note the orientation of the keyway — the new camshaft may have a different keyway position.

Step 4: Remove the Old Camshaft

Loosen and remove all cam bearing cap bolts in a gradual, crisscross pattern (10 mm bolts). The B16A2 has four main caps (arched side up). Label each cap or lay them in order to avoid mixing caps. Each cap is machined specifically to its journal; swapping caps can cause binding or seizure.

Carefully lift the camshaft straight out of the head. Avoid dragging the lobes across the bearing surfaces. Inspect the old cam lobes and journals for scoring or excessive wear — this indicates oiling issues that must be addressed before installing the new cam.

Remove the rear cam plug (if present) using a pick tool. Clean the cam journal bores with brake cleaner and a lint-free cloth.

Step 5: Install the New B16A2 Camshaft

Coat the new camshaft’s journals and lobes with clean engine oil or dedicated assembly lube. Slowly lower the cam into the head, ensuring the lobes align with the valve lifters (tappets). Verify VTEC components: The new cam should have the VTEC rocker pin slots and the spool valve clearance. If using an aftermarket cam, confirm it is compatible with the B16A2’s VTEC engagement profile (e.g., 5500 RPM vs. 6000 RPM).

Apply a thin smear of assembly lube to the lifters’ contact pads. Some aftermarket cams require different valve lash settings — consult the cam card. For OEM-style camshafts, lash is typically 0.006–0.008 inches (intake) and 0.007–0.009 inches (exhaust) with the engine cold.

Reinstall the cam bearing caps in the correct order and orientation. Tighten the cap bolts gradually in four passes to the factory torque of 7.2 ft-lb (86 in-lb). Use a inch-pound torque wrench for precision. Over-tightening can distort the cam bore.

Step 6: Install Camshaft Seals and Sprocket

Press in the new front cam seal (using a seal driver or deep socket of appropriate diameter). Ensure it is seated flush with the housing. Lightly lubricate the lip of the seal with grease. Install the rear cam plug with a new O-ring (if applicable) or a bead of RTV.

Position the cam sprocket onto the camshaft, aligning the keyway. Torque the center bolt to 59 ft-lb using the cam holder tool. Do not rely on the timing belt to hold the cam — it will slip.

Step 7: Reinstall the Timing Belt

Rotate the cam sprocket so that the UP mark is at 12 o’clock and the small timing mark aligns with the cylinder head surface. Rotate the crankshaft to exactly TDC (pulley mark aligned). Install the timing belt, ensuring tension is applied to the tensioner side (driver side). Cycle the tensioner to take up slack, then tighten the tensioner bolt to 33 ft-lb.

Manually rotate the crankshaft two full revolutions clockwise. Recheck all timing marks — they must still align. If they do not, the belt was installed incorrectly, or the tensioner needs adjustment.

Step 8: Reinstall the Valve Cover

Clean the valve cover and head mating surfaces thoroughly. Apply small dabs of high-temp RTV to the corners where the cam caps meet the head (as per factory service manual). Install a new valve cover gasket and grommets. Seat the cover gently, then tighten the 12 bolts in a crisscross pattern to 7 ft-lb (84 in-lb). Over-tightening cracks the cover.

Step 9: Reassemble the Engine Bay

Reattach the spark plug wires, ignition coils, vacuum hoses, and any brackets removed earlier. Reinstall the engine cover. Double-check that all electrical connectors are fully seated and no tools remain in the engine bay. Reconnect the negative battery terminal.

Post-Installation: Startup and Break-In

Start the engine and let it idle for about 15–20 minutes. Listen for any tapping or knocking sounds — a few seconds of tapping as the hydraulic lifters fill with oil is normal, but persistent noise indicates incorrect lash or a binding cam. Check the timing belt cover and cam seals for oil leaks. Monitor the coolant temperature and ensure the engine does not overheat.

After the break-in idle, perform a visual inspection. Tighten any loose bolts. Then take the vehicle for a gentle test drive, avoiding full throttle until the engine reaches operating temperature. Gradually increase engine speed up to 6000 RPM, but avoid sustained high RPM for the first 100 miles to allow the cam lobes to wear-in against the lifters.

Performance Tuning and ECU Considerations

A camshaft swap without ECU tuning often results in a check engine light, rough idle, or lost power. The factory ECU is calibrated for the stock cam’s overlap and lift. A 15–20 hp gain is only achievable with proper fuel and ignition mapping. Use a reputable tuner or flash tool (e.g., Hondata S300, Neptune, or K-Tuner) to adjust:

  • VTEC engagement point (lower or raise depending on cam)
  • Fuel enrichment at high RPM
  • Ignition timing advance/retard for overlap
  • Idle air control (IAC) settings for lumpy cams

If you have installed an aggressive aftermarket cam with higher lift than 0.400 inches, consider upgrading valve springs and retainers to prevent valve float. For the B16A2, retainers are typically fine up to 0.410 inches, but check with your cam manufacturer.

Expected Performance and Real-World Results

When paired with a cold-air intake, a 2.5-inch exhaust system, and a Hondata tune, a B16A2 cam upgrade can produce peak gains of 15–20 hp at the wheels, with a broadened torque curve from 4500–7800 RPM. The stock B16A2 redline is 8200 RPM; many aftermarket cams shift power higher, so setting a new redline at 8400–8600 RPM is common. Expect a noticeable increase in top-end pull and a more aggressive VTEC crossover sound.

For reference, the factory B16A2 cam has 0.350/0.345 inch lift and 240° duration. An aftermarket cam like the Skunk2 Turbo Stage 1 (0.400/0.400, 256°) provides a stronger midrange, while the Pro Series (0.480/0.480, 268°) is better suited for track use with supporting mods.

Conclusion

Installing a B16A2 camshaft is a gratifying weekend project that transforms the character of your Honda’s engine. By following this detailed step-by-step guide, using quality tools, and respecting critical torque specifications, you can unlock a reliable 15–20 hp increase. Remember that tuning is the key to realizing full gains — budget for an ECU calibration or a standalone unit. With proper installation and setup, your B16A2 will rev higher, breathe better, and deliver a driving experience that justifies every hour of wrenching.