G3408 and G3412 Engines Caterpillar

Note: For more information, refer to the following publications: Guidelines for Reusable Parts, SEBF8002, "Valve, Valve Springs, Valve Rotators and Locks" and Guidelines for Reusable Parts, SEBF8034, "Valve and Valve Spring Specifications".

Illustration 1	g00936308

(1) Spring

Inside diameter ... 21.996 mm (0.8660 inch)

Test length ... 42.18 mm (1.661 inch)

Free length after test ... 62.74 mm (2.470 inch)

(2) Distance from the top of the cylinder head to the top of the valve guide ... 32.3 ± 0.80 mm (1.27 ± 0.03 inch)

(3) Bore in a new valve guide that is installed in the cylinder head ... 9.487 ± 0.025 mm (0.3735 ± 0.0010 inch)

(4) Diameter of valve head

Exhaust valve ... 41.81 ± 0.13 mm (1.646 ± 0.005 inch)

Inlet valve ... 44.98 ± 0.13 mm (1.771 ± 0.005 inch)

Prior to installation of the valves, coat the valve stems with clean engine oil.

Illustration 2	g00936309

(5) Depth of the bore in the cylinder head for the valve seat insert ... 11.48 ± 0.1 mm (0.452 ± 0.004 inch)

Note: The valve seat inserts do not require machining after installation.

(6) Diameter

Diameter of exhaust valve seat insert ... 42.840 ± 0.013 mm (1.6866 ± 0.0005 inch)

Bore in the cylinder head for the exhaust valve seat insert ... 42.774 ± 0.025 mm (1.6840 ± 0.0010 inch)

Diameter of inlet valve seat insert ... 46.025 ± 0.013 mm (1.8120 ± 0.0005 inch)

Bore in the cylinder head for inlet valve seat insert ... 45.949 ± 0.025 mm (1.8090 ± 0.0010 inch)

Temperature of the valve seat inserts for installation into the bores in the bottom of the cylinder head ... -62 °C (-80 °F)