G3408C and G3412C Engines Caterpillar

Note: Refer to Reuse And Salvage Guidelines, SEBF8002, "Valves, Valve Springs, Valve Rotocoils, and Locks" and refer to Reuse And Salvage Guidelines, SEBF8034, "Valve and Valve Spring Specifications" for the procedure and specifications in order to check used valves and valve springs.

Illustration 1	g01405439

(1) 4N-5906 Spring

Length under test force ... 54.99 mm (2.165 inch)

Test force ... 344 ± 34 N (77.3 ± 7.6 lb)

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

Outside diameter ... 31.75 mm (1.250 inch)

(A) Height to top of valve guide

Inlet valve guide ... 26.00 ± 0.80 mm (1.024 ± 0.031 inch)

Exhaust valve guide ... 32.30 ± 0.80 mm (1.272 ± 0.031 inch)

Note: Apply clean engine oil to the valve stems prior to installation in the cylinder head.

(B) Diameter of new valve stem

Inlet valve ... 9.441 ± 0.008 mm (0.3717 ± 0.0003 inch)

Exhaust valve ... 9.441 ± 0.010 mm (0.3717 ± 0.0004 inch)

(C) Diameter of valve head

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

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

(D) Angle of valve face ... 19.25 ± 0.25 degrees

Illustration 2	g01405441

Note: The temperature of the valve seats for installation into the bores in the bottom of the cylinder head is -62 °C (-80 °F).

(E) Bore in cylinder head for valve seat

Inlet valve seat ... 45.949 ± 0.025 mm (1.8090 ± 0.0010 inch)

Exhaust valve seat ... 42.774 ± 0.025 mm (1.6840 ± 0.0010 inch)

Note: The valve seats do not require machining after installation.

(F) Angle of face of valve seat

Inlet valve seat ... 20.25 ± 0.50 degrees

Exhaust valve seat ... 20.25 ± 0.25 degrees

(G) Depth of bore in cylinder head for new valve seat ... 11.48 ± 0.10 mm (0.452 ± 0.004 inch)

(H) Outside diameter of the face of the valve seat

Inlet valve seat ... 42.01 mm (1.654 inch)

Exhaust valve seat ... 37.3 mm (1.47 inch)