Upgrading your Acura RSX with a Toda Racing camshaft is one of the most effective ways to unlock genuine horsepower gains from the K20 engine. These precision-ground camshafts are engineered to increase valve lift and duration, shifting the power band higher for a more aggressive, track-oriented feel. While the installation is not trivial for a complete beginner, this guide breaks down every step to ensure a successful swap that delivers reliable, measurable performance improvements.

What You Need for the Camshaft Installation

Before you open the hood, gather all the required parts and tools. Missing a single item can halt the job or lead to engine damage.

Essential Parts

  • Toda Racing camshaft – Choose the correct profile for your RSX model (K20A2, K20A3, or K20Z1). Toda offers different stages; this guide covers a typical Stage 2 street/strip cam.
  • New camshaft seals – Always replace the front and rear cam seals to prevent oil leaks. Use OEM Honda or high-quality aftermarket seals.
  • New valve cover gasket – The gasket often deforms after removal. A fresh one ensures a perfect seal.
  • Engine oil and assembly lube – You’ll need 5W-30 or recommended viscosity for your climate. Assembly lube prevents dry-start wear on lobes and journals.
  • Camshaft installation tool – A dedicated tool helps compress valve springs safely when installing cam caps. A universal cam bearing alignment tool can work, but Toda recommends their own fixture.
  • Timing chain tensioner stopper pin – This holds the tensioner compressed during reinstallation. Many aftermarket kits include one.
  • Threadlocker (medium strength) – Use on cam cap bolts and any fasteners that see high vibration.

Required Tools

  • Socket set (metric, 10mm, 12mm, 14mm, 17mm, 19mm)
  • Torque wrench (capable of inch-lbs and ft-lbs)
  • Camshaft bearing cap socket (often 10mm 12-point)
  • Timing chain tool (to hold the cam sprockets)
  • Feeler gauge
  • Pry bar or plastic trim removal tools
  • Clean rags and brake cleaner
  • Service manual for your specific RSX model year

It is strongly recommended to have the factory Honda service manual on hand. Digital copies are widely available on forums like ClubRSX or KSeriesParts.

Preparation Steps

Proper preparation prevents mistakes and damaged parts. Follow these steps before touching the camshafts.

  • Disconnect the negative battery terminal – This cuts power to the ECU and prevents accidental starting during the job.
  • Remove the engine cover and intake air duct – The plastic beauty cover and intake piping must come off to access the valve cover.
  • Drain the engine oil – While not strictly required, draining oil reduces mess if any drips into the valvetrain. It also allows you to install fresh oil immediately.
  • Remove the spark plugs – This relieves compression, making the engine easier to rotate by hand later for timing alignment.
  • Clean the surrounding area – Use brake cleaner and a rag to remove dirt from the valve cover and timing chain cover. Debris entering the engine will cause rapid wear.

Removing the Old Camshafts

This section covers extracting both the intake and exhaust camshafts. Even if you are only replacing one cam, you must remove both to access the caps evenly.

Timing Chain and Cam Sprocket Removal

  1. Rotate the crankshaft to Top Dead Center (TDC) on cylinder #1. Align the crank pulley mark with the timing cover pointer, and ensure the cam sprockets’ marks point upward and are parallel.
  2. Remove the upper timing chain cover (plastic or metal, depending on RSX model). You may need to pry carefully to avoid breaking the gasket.
  3. Install a cam sprocket holding tool to prevent the cams from rotating. If you don’t have a dedicated tool, a chain vice grip wrapped in cloth can work temporarily.
  4. Loosen the cam sprocket bolts. The intake cam bolt is typically 17mm, exhaust 14mm. Use a breaker bar. Do not remove the bolts yet – just break them loose.
  5. Compress the timing chain tensioner. Press the tensioner arm in and insert a stopper pin (or a 1.5mm Allen key) through the hole in the tensioner body to hold it.
  6. Remove the cam sprocket bolts completely. Slide the sprockets off the camshaft noses, but keep them resting on the chain guides. It helps to wire them in place so they don’t fall into the chain case.

Camshaft Cap Removal

Valve cover removal is straightforward, but the cam caps require care. They are specific to each position and must be reinstalled exactly as removed.

  • Unbolt the valve cover in the reverse of the tightening sequence (outer to inner). Set it aside.
  • Using a 10mm 12-point socket, loosen each cam cap bolt in three stages – starting from the center caps and working outward. This prevents warping the caps.
  • Label each cap with a marker or place them in a numbered tray. The caps are not interchangeable; mixing them can destroy the cam journals.
  • Lift the caps off. You may need to gently tap them with a rubber mallet to break the seal if old gasket adhesive is present.
  • Carefully lift out the old camshafts. Place them in a clean area. Note the location of the dowel pins and any thrust washers.

Installing the Toda Racing Camshaft

With the old cams out, it’s time to install the Toda units. Follow these steps precisely to avoid damaging the new cams or your engine.

Pre-Lubrication

Apply a generous amount of assembly lube or clean engine oil to the following areas:

  • The camshaft bearing journals (both the cam lobes and the cap surfaces).
  • The front and rear cam seal bores.
  • The camshaft lobes themselves – especially the high-lift regions.
  • The thrust surfaces that contact the front bearing cap.

Positioning the New Camshafts

  1. Place the intake camshaft into the head. The Toda cam will have a distinct marking or laser etching indicating intake or exhaust. Confirm you have the correct cam.
  2. Install the exhaust camshaft similarly. Ensure the cam gear alignment dowels are facing upward and in the proper orientation (intake dowel at 12 o’clock, exhaust at 9 o’clock for TDC).
  3. Apply a thin layer of engine oil to the new cam seal lips. Press the seals into the front of the head using a seal driver or a deep socket of the same diameter.

Reinstalling Cam Caps and Torquing

  • Place the cam caps in their correct positions according to your markings. Ensure the arrows or numbers on the caps face the same direction as originally installed (usually toward the timing chain side).
  • Hand-tighten all cap bolts in the specified tightening order: start at the center caps, then alternate outward. Refer to the service manual for the exact sequence.
  • Torque the bolts in three increments: first to 7 ft-lb, then to 12 ft-lb, finally to the factory specification of 16 ft-lb (20 Nm) for K20 engines. Use a beam or click-type torque wrench. Do not guess.
  • After torquing, check that the camshaft rotates freely by hand using the cam sprocket hex. If it binds, you may have a cap alignment issue – loosen and re-torque in sequence.

Reinstalling Timing Chain and Sprockets

The most critical part of the job is correctly timing the cams to the crankshaft.

  1. Rotate the crank back to TDC if it moved during cap removal.
  2. Place the intake sprocket onto the cam – its keyway should align with the dowel pin. Install the cam bolt finger-tight.
  3. Do the same for the exhaust sprocket. Ensure the timing marks on the sprockets line up with the marks on the timing chain guides or the backing plate.
  4. Remove the tensioner stopper pin to apply tension to the chain. Rotate the engine by hand two full turns to verify that the timing marks realign. If they do not, you must correct the chain position.
  5. Torque the cam sprocket bolts to 61 ft-lb (83 Nm) for the intake and 44 ft-lb (60 Nm) for the exhaust. Use threadlocker on the bolts.

Post-Installation Tuning and Break-In

Running the engine with a Toda Racing camshaft without proper tuning can cause poor idle, stalling, or even detonation. The cam profile alters airflow enough that the stock ECU will struggle to adapt.

ECU Reflash or Standalone Tuning

Most RSX owners pair Toda cams with a Hondata ECU reflash or a full standalone system like K-Pro or Haltech. A professional dyno tune is recommended to optimize air/fuel ratios and ignition timing. Expect to gain 15–25 wheel horsepower on a naturally aspirated K20 with stage 2 cams and supporting mods.

Valve Lash Adjustment

After installation and before the first start, check and set the valve clearances. Toda cams often require tighter lash than stock. Typical intake clearance: 0.006–0.008 inches; exhaust: 0.008–0.010 inches. Use a feeler gauge and a wrench to adjust the tappet screws. Refer to the camshaft spec sheet from Toda Racing for exact numbers.

Break-In Procedure

  • Fill the engine with fresh oil and a new filter. Use a high-quality 5W-30 synthetic.
  • Start the engine and let it idle for 20 minutes at 2000–2500 RPM. Do not hold a steady idle below 2000 RPM during break-in – the lobes need splash lubrication.
  • After idle break-in, perform a gentle road test. Vary engine speed but avoid sustained high RPM (above 5000) for the first 100 miles.
  • Change the oil and filter after the break-in period. Inspect the oil for metallic debris; a normal amount of fine particles is acceptable.

Common Pitfalls and Troubleshooting

Even experienced mechanics can run into issues. Watch for these problems:

  • Cam cap bolt cross-threading – Always hand-start bolts. If you feel resistance, stop and retap the threads.
  • Timing chain skipped a tooth – If the engine runs rough or backfires, recheck timing alignment. A tooth off can bend valves.
  • Oil leak at cam seals – Ensure the seal lips are not damaged during installation. A thin coat of oil on the inside lip helps.
  • Cam lobes hitting valve retainers – Toda cams have higher lift. If you have aftermarket valves or retainers, check for clearance with light putty on the piston crown (clay test).

Conclusion

Installing a Toda Racing camshaft on your Acura RSX is a rewarding project that transforms the character of the K20 engine. The power increase is real and the sound is intoxicating. By following this expanded guide, you can avoid the common mistakes that lead to engine damage and ensure a long, reliable life for your new camshaft. Pair the installation with a proper tune and you will have a daily driver that performs like a track weapon. For further reading and community support, check out Honda-Tech and 2NR – two excellent resources for K-series enthusiasts.