Camshafts should be visually checked before their installation and camshaft end play should be determined before camshaft removal. To perform this process start by removing the cable that is connected to negative terminal of the battery and remove also the valve cover. Align the engine of the piston at the Top Dead Center on the compression stroke for the number 1 cylinder and apply a drop of paint on the links of timing chain touching the timing marks of the camshaft sprockets. Before loosening the sprocket bolts, the first step to follow is to use a wrench to hold the camshafts from turning; also, the hex-shaped lug on the camshaft has to be held from turning as well, before turning the camshaft sprocket bolts several turns counter-clockwise. For the models of 1999 to 2007, take off the timing chain tensioner from the timing chain cover and the camshaft position sensor from the cylinder head. Once again, for the 2008 and later models, twist the timing chain cover and tensioner screws in a counter clockwise direction to take out the chain cover and tensioner. Both the crankshaft sprocket and the camshaft sprockets bolts are to be withdrawn, the timing chain disconnected from such sprockets and the sprockets themselves to be separated from the engine clean; in doing so, the Variable Valve Timing (VVT) actuator will be identified. On the models of 1999-2007 while being engaged in the timing chain replacement, move the chain aside and stuff some cloth in the hole on the timing chain cover to prevent debris from falling directly onto the engine. Check the camshaft bearing caps and identify their orientation by matching the number on them and the cylinder head, slightly loosen in the reverse of the lightening order, remove the bearing caps and take out the camshaft(s), labeling as 'Intake' or 'Exhaust'. Another freeze the lifters on the cylinder head and remove them, arranged in order, and inspect the camshaft, Camshaft bearing and the lifter for any sign of wear Starting with the 2008 model year or later, the camshaft housing bearing cap bolts are loosened in the sequence shown in the illustration, and the camshaft housing and these camshaft bearing caps, oil control filter, and camshafts are removed. Check the camshafts for wear and when carrying the check also consider checking the camshaft bearings, camshaft housing, the rockers, and the lash adjusters. This must be done before the camshafts are pulled: camshaft endplay is measured with a dial gauge and the camshaft bearing surfaces are inspected for wear. Check the outer diameter of each camshaft bearing journal and the inner diameter of each corresponding camshaft bearing to get oil clearance. Check the height from the camshaft to each lobe and measure the amount of camshaft run out. Check the lifters for wear and to obtain the outside diameter to ascertain the quantities of oil clearance. For installation on models from 1999 to 2007, which were sent without No.1 journal bearings, place them on the cylinder head, apply camshaft installation lubricant on the camshaft lifters and journals before installing camshaft. Screw the bearing caps and bolts in and fasten them and mesh the teeth of camshaft sprocket with the links of timing chain such that the marks match. Finally fit the remainers of the timing chain and reassemble in the reverse order for 2008 and later models put oil on the rocker arms and the lash adjusters to also ensure that the dowel pins are in the right place. Coat the camshaft housing to cylinder head contact surface with seal packing, set camshaft housing in position and fasten screws properly while tightening the bolts, after which operation of the engine should not be carried out for at least 4 hours to avoid leakage of seal packing. Last step of the installation is the camshaft sprockets, the timing chain, and last but not the least the timing chain cover.
Posted by LexusPartsNow Specialist 
