To remove the components, first disconnect the cable from the negative terminal of the battery. Next, remove the intake plenum and the valve covers, then disconnect the electrical connectors at the camshaft position sensors and remove the sensors. Proceed to remove the timing chains and camshaft sprockets, and for models without exhaust timing control, remove the variable intake valve timing valves from the top of the number one camshaft journals. Mark the camshaft bearing caps from 1 to 4, indicating intake or exhaust, and ensure arrows point to the front of the engine. Loosen the camshaft bearing caps in reverse order of tightening, keeping them in order for reinstallation. Remove the bearing caps and camshafts, noting the markings for correct installation. Remove the lifters from the cylinder head, keeping track of their original positions, and measure each journal diameter with a micrometer, replacing the camshaft if any journal is below the specified limit. Visually inspect the camshaft lobes, journals, bearing caps, and lifters for wear or damage, and measure camshaft journal diameter and lobe height, replacing the camshaft if any measurements are below specifications. Check camshaft runout and endplay, replacing the camshaft or cylinder head if limits are exceeded. Inspect each lifters for scuffing and check oil clearance for each camshaft journal using Plastigage, replacing components if clearance is greater than specified. For installation, remove old RTV sealant, set the number one piston at TDC, lubricate and install the lifters, apply assembly lubricant to the camshaft lobes and journals, and install the exhaust camshafts with dowel pins facing up. Apply RTV sealant to the sealing surfaces and install new O-rings on the secondary timing chain tensioners. Install the bearing caps and bolts, tightening them in sequence, and check the protrusion of the front bearing caps. Install the camshaft sprockets and timing chain, holding the camshafts with a wrench while tightening the sprocket bolts. Complete the installation in reverse order of removal, checking and adjusting valve clearance if any part of the valve train was replaced, and finally reconnect the battery and perform necessary relearn procedures, especially for specific models if the Exhaust Valve Timing components were disconnected or removed.
