Lexus 13054-20030 Camshaft Sub-Assy, NO.4

Before beginning this procedure, obtain two 6 x 1.0 mm bolts that are 16 to 20 mm long. Position the engine at TDC, then remove the valve covers, the timing belt, and the camshaft sprocket. The following steps apply to the removal of each of the four camshafts: secure the exhaust camshaft subgear first, remove the intake cam, then remove the exhaust camshaft. Ensure the cam timing marks on the drive and driven gears are in alignment; on the right cylinder head, align the two dots on the intake camshaft gear with the two dots on the exhaust camshaft gear, and on the left cylinder head, align the one dot on the intake camshaft gear with the one dot on the exhaust camshaft gear. Secure the exhaust camshaft sub-gear to the driven gear with a service bolt installed in the threaded hole, then use a two-pin spanner to remove the tension from the sub-gear and remove the service bolt before releasing the sub-gear. Loosen the intake camshaft bearing cap bolts in 1/4-turn increments until they can be removed by hand, starting with the outer caps and working inward. Remove the bearing caps and gently lift out the intake camshaft, keeping it level. Repeat the loosening and removal process for the exhaust camshaft bearing caps and oil seal, then gently lift out the exhaust camshaft, ensuring it remains level. Store the bearing caps in the correct order, and if necessary, remove the valve lifters and shims with a magnetic tool, storing them separately to avoid mix-ups. To disassemble an exhaust camshaft gear, mount the cam in a vise and install a second service bolt in the unthreaded hole in the camshaft sub-gear, using a screwdriver to rotate the sub-gear clockwise and remove the first service bolt. Remove the sub-gear snap-ring and then the wave washer, sub-gear, and camshaft gear spring from the exhaust camshaft, keeping parts from the rear cylinder head separate from those of the front. If the VVT assembly is to be removed, hold the hex portion of the camshaft in a vise and use a breaker bar and 46mm socket, noting that the nut is a left-hand thread. For inspection, follow the camshaft, lifter, and related component inspection procedures using the specifications for the V6 engines. For installation, reassemble the exhaust camshaft gear(s) by installing the camshaft gear spring, sub-gear, wave washer, and snap-ring, then mount the camshaft in a padded vise. Insert a service bolt into the unthreaded hole in the camshaft sub-gear, align the holes of the camshaft driven gear and sub-gear by turning the camshaft sub-gear clockwise, and install a second service bolt in the threaded hole, tightening it to clamp the gears together. Apply moly-base grease or engine assembly lube to the lifters and install them in their original locations, ensuring the valve adjustment shims are in place. Apply camshaft installation lubricant to the exhaust camshaft lobes, bearing journals, and gear thrust faces, then set the exhaust camshaft in place in the cylinder head with the timing mark on the sub-gear facing the center of the head. Apply a thin coat of RTV sealant to the outer edges of the front bearing cap-to-cylinder head mating surfaces, install the bearing caps in numerical order with the arrows pointing toward the timing belt end of the engine, and tighten the bearing cap bolts in 1/4-turn increments, starting with the center cap and working outward. Install a new camshaft oil seal, apply camshaft installation lubricant to the intake camshaft lobes, bearing journals, and gear thrust faces, and if the VVT assembly was removed, install it with its groove aligned with the pin on the camshaft, oil the threads, and install a new nut. Set the intake camshaft in place in the cylinder head, aligning the timing mark with the exhaust camshaft timing mark, then install the bearing caps in numerical order with the arrows pointing toward the front of the engine, tightening the bearing cap bolts in 1/4-turn increments. Remove the service bolt from the exhaust camshaft sub-gear, reinstall the timing belt rear cover, the camshaft sprockets, and the timing belt, inspecting the gasket on the timing belt rear cover and repairing or replacing it as necessary. Reinstall the remaining components in the reverse order of removal, apply RTV sealant in the indicated areas before reinstalling the valve covers, clean the rubber half-circle plugs for the back of the heads, and reinstall them with new RTV sealant. Finally, run the engine and check for leaks and proper operation.

During these years' repairs, always check the camshaft condition first before installing, and measure camshaft movement before removing it from service. Make sure to disconnect the cable from the negative battery terminal, and next take off the valve cover. Pin your engine down at TDC on its compression stroke, number 1 cylinder running. Add a spot of paint where the timing chain meets timing marks on the camshaft sprockets. Before taking out the camshaft sprocket bolts, use a wrench to keep the camshafts from turning. Loosen each bolt a few turns with the wrench. Take off the timing chain tensioner from its housing at the cover and the camshaft position sensor from the head of the cylinder. Loosen the timing chain cover opening to remove the camshaft sprocket retaining bolts. Then, slide off the timing chain from each sprocket and take out the camshaft sprockets from the engine block. Be sure to secure the timing chain while it hangs away from the engine and cover the opening with a rag to stop debris from entering. To disconnect the camshafts, loosen their bearing caps in a specific order, move the caps off the head, tag the camshafts "Intake" or "Exhaust" to keep them from mix-ups. When you take off each lifter from the cylinder head, put it back with its matching valve and cylinder, and check the camshafts, camshaft bearings, and lifters for any sign of deterioration. Use a dial indicator to check camshaft endplay before you take out the camshafts. Look closely for harm to the camshaft bearing locations in the cylinder head. Comparison of camshaft bearing journal diameters against factory specifications. Check the camshaft lobe length and how true the camshaft runs on its axis. Look for wear on the lifters and get their outer size to figure the amount of oil they allow through. During installation, slide the No.1 journal bearings back into the cylinder head, then apply lubricant to both the camshaft's lobes and journals before putting the camshaft back. Since the bolts connecting the bearing caps won't use tools to secure them when they're first tightened, be sure to do so by hand and start by tightening them uniformly. Fit the timing chain teeth into the camshaft sprocket, making sure each mark on the chain points to the correct spot on the camshaft, then verify that all timing sprockets are seated properly before tightening the camshaft sprocket bolts. Swing the timing chain tensioner in place, lubricate the valve adjusters, and put them into their slots on top of the engine block. Put oil onto the rocker arms before attaching them, making sure each one sits directly on its matching lash adjuster. Screw the camshaft bearings and oil control valve filter into the camshaft housing, then put the camshaft into its place within the housing and tighten the bearing cap screws. With the rocker arms in place, make sure the dowel pins point up when you install them, and put a bead of seal packing along where the camshaft housing contacts the cylinder head. Put the camshaft housing on to the cylinder head and fasten these bolts. Do not lubricate or start the engine for four hours after assembly. Install the sprockets on the camshaft, put the timing chain and timing chain cover back in place, and undo what was taken apart when you removed the camshaft.

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.