1ZZ and 2ZZ Intake Cam VVT Sprocket Unlock

There’s a problem! If you bolt a new OEM or QRP VVT intake sprocket on to a 1ZZ or 2ZZ camshaft in the locked (default) position and torque the center bolt it will STICK in the locked position and never adjust. This results in terrible performance and a check engine light.

When you buy a new or reconditioned 1ZZ/2ZZ VVT sprocket from MWR it should arrive unlocked. Be careful not to rotate it after install until you’ve torqued the center bolt. After torqueing center bolt you should be able to easily rotate the sprocket clockwise a few degrees, then it’ll get to the locked position and stick there. Sprocket will function properly as long as it locked AFTER center bolt was torqued.

Reinstalling a used VVT sprocket on a cam?  You can unlock it using:




This is how we do them at MWR. It works great, doesn’t require compressed air, and gives you the advantage of inspecting and cleaning the inside of the sprocket.

  1. Bolt intake camshaft into cylinder head.
  2. Install locked VVT sprocket to intake cam, rotated to proper position so dowel pin from camshaft engages the groove in the sprocket, with center bolt in place but finger tight (NOT TORQUED)
  3. Using vise grip plyers or other method, remove the 4 tamper proof VVT sprocket bolts. This is easy with the early type external 5-sided bolt heads (shown in pic above). You need the special 5-sided security torx bit (rare!) to remove the security torx-type bolts found in the later model sprockets.
  4. Be careful to only make the alterations described- if you start sliding this thing apart and let the little wiper seals out then getting it all back together may be very difficult.
  5. Remove cover plate.
  6. Remove small coil spring that is sticking out, and use a small screwdriver or pick to pull locking pin outward until it’s flush with the end of the sprocket.
  7. Rotate sprocket counter clockwise appx 30 degrees until it hits its stop.
  8. If inside of sprocket is a bit dirty you can spray some cleaning solution in to rinse it out. If it is heavily sludged, excessively worn or contains metallic debris the sprocket should be discarded and replaced with a new one.
  9. Reinstall coil spring in locking pin, then cover plate, then 4 bolts. We recommend using standard hex head 6MM BOLTS from planet earth, but if you have the proper weirdo 5-sided tool to deal with the stock bolts then feel free to reuse them.
  10. Use a screwdriver or other method to prevent the sprocket from rotating (IMPORTANT) and torque the 4 bolts to 12 Nm. If sprocket rotates and locking pin engages then you must start the entire process over.
  11. Use a crescent wrench to hold hex in middle of camshaft and prevent it from rotating, and torque large center sprocket bolt to 47 Nm.
  12. Rotate sprocket clockwise- it should easily move appx 30 degrees, then lock in place. As long as it locks after you torqued the center bolt you’re all set!!