This is a quick guide to removing and reinstalling the camshafts of the 2ZZ or 1ZZ engine with the engine installed in the car. Focus is on minimal disassembly and parts removal since the engine bay is tight and we’re looking to minimize project time. This is how we do it in house at MWR; if you are more comfortable taking a bit more time and removing all of your accessories and the crank pulley and the timing cover then by all means do it as the OEM service manual suggests. Either operation should only be attempted by an experienced mechanic; severe engine damage may occur if timing is set wrong or if something comes loose after engine is restarted!
The product links provided throughout the writeup are for 2zz parts- we do also offer the 1zz equivalents, just do a search or find them in their categories.
- Turn the crankshaft until the timing mark on the pulley aligns with the 0 on the timing cover.
- Remove coils and valve cover (supercharged Lotus application must have intercooler removed first).
- Apply alignment paint marks to the chain and the intake and exhaust sprockets so that you can get the cam timing correct during reinstallation.
- Remove belt, then loosen the main pivot bolt and the top nut that secure the belt tensioner to the engine. You don’t need to completely remove the tensioner, just move it over slightly to gain access to chain tensioner.
- SLIGHTLY loosen the large bolt that secures the exhaust cam sprocket to the exhaust camshaft. Just break it free, do not remove it.
- Remove the chain tensioner from the upper rear area of the timing cover. It is two small nuts, then will slide right out.
- Holding the chain up in the middle so it does not drop down into the timing cover area, remove the exhaust cam sprocket from the exhaust cam. The chain can’t skip on the crankshaft but it can get jammed up down there if it falls in.
- Remove the camshaft caps from the cylinder head to allow you to remove the intake cam, exhaust cam or both depending on your needs. Keep that chain pulled upward so it doesn’t fall!
- If you are installing new valve springs and/or valve seals, do so now (1ZZ) or while rockers are removed in the next step (2ZZ).
- If you are swapping out damaged rockers (2ZZ) then get everything out of the way and remove the VVL block (5 nuts and bolts) from the left side of the cylinder head. Remove the two “lift bolts” which secure the shafts and align them toward the right side of the cylinder head. You can now slide the rocker shafts out toward the left side of the engine, above the transmission, and swap out rockers. Install rockers, reinstall shafts (check that orientation is correct, you may need a mechanic’s mirror to look in from timing cover side), reinstall lift bolts (most people install new ones), and reinstall VVL block.
- If you are installing a new intake cam or have separated the VVT sprocket from intake cam, be sure to UNLOCK the sprocket before reassembly.
- Install intake cam (with sprocket installed and torqued already) and exhaust cam (no sprocket) to cylinder head.
- Be sure painted timing mark on intake cam lines up with paint mark on chain.
- Loosely install sprocket to exhaust cam, making sure exhaust cam sprocket to chain paint marks line up.
- Install cam caps, torque all cam cap bolts to 20 Nm.
- Torque exhaust sprocket bolt to 47 Nm.
- On timing chain tensioner press release lever, collapse tensioner, and swing tiny hook into place to hold it in compressed position.
- Install chain tensioner in timing cover (still compressed), torqueing retainer nuts to 12 Nm.
- With your hand push down on chain between the cam sprockets until you hear the chain tensioner pop free and click, applying tension to chain.
- Check one last time that the paint marks line up, then rotate the crankshaft a full turn to be sure the engine spins freely and there is no piston to valve interference. You can confirm that the OEM Toyota TIMING MARKS on the sprockets line up as they should (will only line up once every 2 revolutions).
- Now is the time to check VALVE LASH if you have installed different cams, rockers or shims during the previous steps. If you need to swap out shims then you will need to repeat some of the above steps to remove cams again to gain access.
- Once you are sure of valve lash being correct, tighten main bolt and upper nut of belt tensioner, then reinstall belt.
- Apply a dab of RTV where timing cover and head meet at the top, then reinstall valve cover (torque 12 Nm) and coils. If it is old then it is a good idea to replace the GASKET and SPARK PLUG TUBE SEALS.