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ROCKER ARM / ADJUSTER DESCRIPTION The rocker arms are steel stampings with an inte- gral roller bearing. The rocker arms incorporate a 2.8 DIAGNOSIS AND TESTING - HYDRAULIC LASH A tappet-like noise may be produced from several items. Check the following items. (1) Engine oil level too high or too low. This may cause aerated oil to enter the adjusters and cause (2) Insufficient running time after rebuilding cylin- der head. Low speed running up to 1 hour may be (3) Turn engine off and let set for a few minutes before restarting. Repeat this several times after (4) Low oil pressure. (5) The oil restrictor in cylinder head gasket or the oil passage to the cylinder head is plugged with (6) Air ingested into oil due to broken or cracked oil pump pick up. (7) Worn valve guides. arm ears contacting valve spring retainer. (9) Rocker arm loose, adjuster stuck or at maxi- mum extension and still leaves lash in the system. (10) Oil leak or excessive cam bore wear in cylin- der head. (11) Faulty lash adjuster. installed in cylinder head and cam on camshaft at • Remove suspected lash adjusters, and replace. • Before installation, make sure adjusters are at least partially full of oil. This can be verified by little REMOVAL NOTE: Disconnect the battery negative cable to pre- (1) Remove the cylinder head cover (Refer to 9 - ENGINE/CYLINDER HEAD/CYLINDER HEAD COVER(S) - REMOVAL). (2) For rocker arm removal on cylinders 3 and 5 Rotate the crankshaft until cylinder #1 is at TDC (3) For rocker arm removal on cylinders 2 and 8 Rotate the crankshaft until cylinder #1 is at TDC (4) For rocker arm removal on cylinders 4 and 6 Rotate the crankshaft until cylinder #3 is at TDC (5) For rocker arm removal on cylinders 1 and 7 Rotate the crankshaft until cylinder #2 is at TDC (6) Using special tool 8516 Rocker Arm Remover, press downward on the valve spring, remove rocker INSTALLATION CAUTION: Make sure the rocker arms are installed NOTE: Coat the rocker arms with clean engine oil Fig. 44 Valve Assembly Configuration 1 - VALVE LOCKS (3–BEAD) 9 - 160 ENGINE 4.7L AN INTAKE/EXHAUST VALVES & SEATS (Continued) |