ENGINE AR 7E1010 - Caterpillar

Cylinder Head And Valves
Illustration 1 g00468536
Cross section of the inlet valve and the exhaust valve in the cylinder head
Illustration 2 g00458090
Cylinder head and valves (typical example)
(1) Collet
(2) Valve spring retainer
(3) Valve spring
(4) Valve guide seal
(5) Recess for valve spring
(6) Valve guide
(7) Exhaust valve
(8) Inlet valve
(9) Valve face angle
(10) Head of exhaust valve
(11) Head of inlet valve
(12) Cap
(13) Valve guide seal
(14) Cylinder head
(15) Cylinder head gasket
(16) Pushrod
(17) Valve seat insert
(18) Valve lifter The valves and the valve mechanism control the flow of air into the cylinders during engine operation. The valves and the valve mechanism control the flow of exhaust out of the cylinders during engine operation. The cylinder head assembly has two valves for each cylinder. Each valve has one valve spring (3). The ports for inlet valve (8) and exhaust valve (7) are on the left side of the cylinder. Steel valve seat inserts (17) are installed in cylinder head (14) for both inlet valve (8) and exhaust valve (7). The seat face angle is equal to valve face angle (9). The valve seat inserts can be replaced.The valve moves along a steel valve guide (6). The valve guides can be replaced.The inlet valve and the exhaust valve are opened and closed by the rotation and movement of the following components:
Crankshaft
Idler gear
Camshaft
Valve lifters
Pushrods
Rocker arms
Valve springsThe camshaft gear is driven by the idler gear. The camshaft gear, the idler gear and the crankshaft gear are timed together. When the camshaft turns, the valve lifters are moved up and down. The pushrods move the rocker arms. The rocker arms make the inlet valves and the exhaust valves open and close. This is in sequence with the firing order of the engine. The valve springs push the valves back to the closed position.