Introduction: Unlocking the H22’s Potential

Upgrading your Prelude H22 with a Skunk2 camshaft is one of the most effective ways to improve mid-range torque and top-end horsepower. The H22 engine, known for its VTEC kick and high-revving nature, responds exceptionally well to a performance cam profile. This guide provides a comprehensive, step-by-step procedure for installing a Skunk2 camshaft – covering everything from tool selection and engine setup to valve lash adjustment and break-in. Whether you are a seasoned DIY mechanic or a dedicated enthusiast, this article will help you complete the swap safely and correctly, ensuring your Prelude delivers the power you expect.

Tools and Materials Needed

Having the right tools on hand before you begin saves time and prevents damage to components. Below is a detailed list of what you will need:

  • Skunk2 performance camshaft (confirm compatibility with your H22 generation – Stage 1, Stage 2, or Pro Series)
  • Socket set with metric sockets (8mm, 10mm, 12mm, 14mm, 17mm, 19mm)
  • Torque wrench (ft-lb and in-lb ranges; ¼-inch and ½-inch drive)
  • Camshaft installation tool or bolt (to prevent cam rotation during cap tightening)
  • New OEM valve cover gasket and spark plug tube seals
  • Camshaft seals (front and rear) – always replace
  • Timing belt kit (if your belt is older than 60,000 miles, replace it now)
  • Gasket scraper and brake cleaner
  • Engine oil – 5W-30 or 10W-40 for break-in; high zinc content recommended
  • Feeler gauge set (for valve lash adjustment – critical with aftermarket cams)
  • Valve lash adjustment tool (socket and wrench for adjusting screw)
  • Thread locker (medium strength) for cam cap bolts
  • Rubber mallet and pry bar (for stubborn camshaft caps)
  • Safety glasses, mechanic’s gloves, and shop rags

Preparation and Safety

Before any work begins, ensure the engine is cool and the vehicle is on a level surface with the battery disconnected (negative terminal first). Drain the engine oil and remove the drain plug – this prevents oil from spilling when you remove the valve cover. Working on a clean engine bay reduces the risk of debris falling into open oil galleries. Also, mark the distributor rotor position if you plan to remove the distributor (recommended for H22 engines to access the front cam cap).

Engine Timing and VTEC Components

On the H22, the camshaft position sensor and VTEC solenoid are mounted near the camshafts. Carefully note the routing of the VTEC wiring and the location of the rocker arm assembly. If you are only replacing the intake camshaft (Skunk2 typically supplies a paired intake/exhaust set), you will still need to remove the VTEC rocker arm sub-assembly for clearance. Label all bolts and keep them organized.

Removing the Old Camshaft

Follow these steps in order. If you have a stock camshaft, its removal is straightforward, but take extra care with the bearing caps – they are matched to the engine block and should be kept in order.

  1. Remove the valve cover. Loosen the bolts in a crisscross pattern to avoid warping the cover.
  2. Remove the distributor (if equipped) and set it aside. Mark the rotor position to make reinstallation easier.
  3. Remove the timing belt upper cover. For full access, you may need to remove the accessory belts and the crankshaft pulley.
  4. Rotate the engine to TDC (top dead center) on cylinder #1. Align the timing marks on the camshaft sprockets and crankshaft pulley.
  5. Remove the timing belt from the camshaft sprockets. Do not rotate the crankshaft once the belt is off.
  6. Remove the camshaft sprockets. Note which is intake and exhaust (H22 uses a toothed wheel for the crank position sensor – do not damage it).
  7. Remove the camshaft bearing caps. The caps are numbered (usually 1-5 from front to rear) and have arrows pointing toward the front of the engine. Loosen each cap a little at a time in a cross pattern.
  8. Lift the old camshaft straight up out of the head. Inspect the journals and lobes for scoring or wear. Clean the bearing saddles with a lint-free rag.

Installing the Skunk2 Camshaft

Before installation, apply a liberal amount of engine assembly lube or clean engine oil to the camshaft journals and lobes. Skunk2 camshafts have a specific lobe profile that requires proper lubrication immediately upon first startup.

  1. Carefully lower the new Skunk2 camshaft into the bearing saddles. Ensure the VTEC lobe (on the intake side if using a dual-pattern cam) is oriented correctly.
  2. Install the bearing caps in their original positions and torque them in two stages. First, snug them to 7 ft-lb (84 in-lb) in a crisscross pattern, then final torque to 14 ft-lb (168 in-lb). Use a torque wrench – over-torquing can warp the caps.
  3. Install new camshaft seals at the front and rear of the head. Apply a thin film of oil to the seal lip before sliding over the camshaft.
  4. Reinstall the camshaft sprockets. Torque the bolt to 44 ft-lb (60 Nm). Verify the timing marks align.
  5. Install the timing belt, tensioner, and covers per the service manual. Rotate the engine by hand two full revolutions to ensure no binding.

Valve Lash Adjustment (Crucial Step)

Skunk2 camshafts have a different base circle than stock, so you must adjust the valve lash (clearance). With the engine at TDC #1, adjust the intake valves to 0.006–0.007 inches and exhaust to 0.007–0.008 inches (cold). Use a feeler gauge between the cam lobe and the rocker arm adjusting screw. Repeat for each cylinder by rotating the crankshaft 180 degrees for each pair. Failure to adjust lash correctly will cause valvetrain noise and potential power loss.

Reassembling the Engine

Once the camshaft and belt are installed, reassembly proceeds in reverse order. Key points:

  • Install the VTEC rocker arm sub-assembly if removed. Torque the rocker arm bolts to 21 ft-lb.
  • Replace the valve cover gasket and spark plug tube seals. Apply RTV silicone to the recommended corners.
  • Install the valve cover and torque the bolts to 7 ft-lb in the proper sequence.
  • Reattach the distributor, ensuring the rotor aligns with the mark you made earlier. If the distributor was removed, set the engine to TDC and align the distributor body accordingly.
  • Refill the engine with fresh oil (synthetic or high-zinc break-in oil) and a new oil filter. Do not use cheap oil – the new camshaft lobes require proper lubrication during first startup.

First Start and Break-In Procedure

Starting a fresh camshaft requires a specific break-in procedure to ensure the lobes and rocker arms mate correctly. Follow these steps:

  1. With the engine running, bring the RPM to 2000-2500 immediately and hold for 20 minutes. Do not let it idle – low oil pressure at idle can scuff the lobes.
  2. During the break-in, listen for any valve float or unusual noise. If you hear a ticking that does not go away after five minutes, shut off the engine, recheck valve lash, and inspect for oil restriction.
  3. After 20 minutes, let the engine idle for 30 seconds, then shut it off. Allow it to cool completely.
  4. Re-torque the camshaft bearing caps and check the timing belt tension. Replace the valve cover gasket if it leaked.
  5. Change the oil and filter after the first 500 miles. Use a high-quality synthetic 5W-30 or 10W-40 for regular driving.

Tuning for Maximum Power

A Skunk2 camshaft changes the engine’s volumetric efficiency dramatically. To fully realize the gains, engine management tuning is highly recommended. Options include:

  • ECU reflash or standalone ECU – adjust VTEC engagement point, fuel maps, and ignition timing. Many tuners set VTEC crossover around 4500-5000 RPM for Stage 1 cams, or 5200-5800 RPM for Stage 2.
  • Adjustable cam gears – fine-tune cam timing for specific RPM bands. Skunk2 often recommends +2° to +4° on the intake and -1° to -3° on the exhaust for their stage 2 cams. This is application-specific.
  • Higher capacity fuel injectors and a larger throttle body may be necessary if you pair the cam with other mods (header, intake).
  • Dyno tuning ensures safe air-fuel ratios and optimal power. A properly tuned H22 with Skunk2 Stage 2 cams can gain 20-30 wheel horsepower over stock.

Common Mistakes and How to Avoid Them

  • Reusing old timing belt components – A broken belt after installation will destroy your new camshaft and pistons. Replace the belt, tensioner, and water pump.
  • Skipping valve lash adjustment – Even if the cam is “drop in,” the base circle difference will cause improper clearance. Always adjust.
  • Not applying assembly lube – The first few seconds of startup are critical. Assembly lube provides cushion until oil pressure builds.
  • Over-tightening cam caps – Use the torque spec exactly. Overtightening can warp the head or caps, causing oil leaks and bearing seizure.

External Resources and Further Reading

For additional technical details and community support, consult these reliable sources:

Conclusion

Installing a Skunk2 camshaft on your Honda Prelude H22 is a rewarding performance upgrade that can transform the engine’s character. The process requires meticulous attention to detail – especially regarding valve lash adjustment, break-in procedure, and tuning. By following this guide and respecting the mechanical tolerances, you can achieve a reliable, powerful H22 that pulls hard to redline. Take your time, use quality parts, and enjoy the improved power delivery that comes from a properly installed aftermarket camshaft.