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VALVES & SEATS - INTAKE/EXHAUST DESCRIPTION The valves are made of heat resistant steel and have chrome plated stems to prevent scuffing. Each valve is actu- STANDARD PROCEDURE - REFACING NOTE: Valve seats that are worn or burned can be NOTE: When refacing valves (4) and valve seats, it 1. Using a suitable dial indicator measure the center of the valve seat Total run out must not exceed 2. Apply a small amount of Prussian blue to the valve seat, insert the valve into the cylinder head, while 3. When the seat is properly positioned the width of the intake seat must be 1.75 - 2.36 mm (0.0689 - 0.0928 in.) and the exhaust seat must be 1.71 - 2.32 mm (0.0673 - 0.0911 in.). 4. Check the valve spring (6) installed height after refacing the valve and seat. The installed height for both intake and exhaust valve springs must not exceed 40.74 mm (1.6039 in.). 5. The valve seat and valve face must maintain a face angle of 44.5 - 45 ° angle . ROCKER ARM-VALVE DESCRIPTION The rocker arms are steel stampings with an integral roller bearing. The rocker arms incorporate a 2.8 mm (0.11 DIAGNOSIS AND TESTING - HYDRAULIC LASH ADJUSTER 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 them to be spongy. 2. Insufficient running time after rebuilding cylinder head. Low speed running up to 1 hour may be required. 3. Turn engine off and let set for a few minutes before restarting. Repeat this several times after engine has reached normal operating temperature. 4. Low oil pressure. 5. The oil restrictor in cylinder head gasket or the oil passage to the cylinder head is plugged with debris. HB ENGINE - 4.7L SERVICE INFORMATION 9 - 1251 |