G3408 and G3412 Engines Caterpillar

Illustration 1	g01381203
Typical example

Note: Refer to Valves And Valve Springs in Guidelines For Reusable Parts, SEBF8002 and in Guidelines For Reusable Parts, SEBF8034 for the procedure and specifications in order to check used valves and valve springs.

(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 ± 0.08 mm (1.024 ± 0.003 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)

The minimum diameter of the valve stems for use in the cylinder head

Inlet valve ... 9.408 mm (0.3704 inch)

Exhaust valve ... 9.408 mm (0.3704 inch)

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

The dimension that can be used again for the valve guide bore ... 9.538 mm (0.3755 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	g01527278

(E) Diameter of valve seat

Inlet valve seat ... 46.025 ± 0.015 mm (1.8120 ± 0.0006 inch)

Exhaust valve seat ... 42.840 ± 0.015 mm (1.6866 ± 0.0006 inch)

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

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)

(G) Angle of face of the valve seat

Inlet valve seat ... 20.25 ± 0.50 degrees

Exhaust valve seat ... 20.25 ± 0.25 degrees

(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)

(J) Use the maximum permissible dimension for new inlet valves and exhaust valves. The dimension is from the end of a closed valve to the machined face of the head.

Dimension below the machined face ... 0.960 mm (0.0378 inch)

Dimension above the machined face ... 0.060 mm (0.0024 inch)

(K) Thickness for reusable valve lip

Exhaust valve ... 2.03 mm (0.080 inch)

Inlet valve ... 2.51 mm (0.099 inch)