3408C, 3412C and 3412D High Performance Marine Engines Caterpillar

Note: The Guidelines for Reusable Parts, Valves and Valve Springs has the necessary procedure and specifications for checking used valves and springs.

Illustration 1	g00355375

(1) 4N-5906 Spring

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

Test force ... 344 ± 34 N (77 ± 7.6 lb)

Length of spring at valve open position ... 42.93 mm (1.690 inch)

Minimum load at the valve open position ... 880 ± 44 N (198 ± 10 lb)

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

Outside diameter ... 31.75 mm (1.250 inch)

(2) Height to top of valve guide ... 32.3 ± 0.8 mm (1.27 ± 0.03 inch)

(3) Diameter of new valve stem ... 9.441 ± 0.010 mm (.3717 ± 0.0004 inch)

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

Exhaust valves ... 9.408 mm (0.3704 inch)

Inlet valves ... 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)

(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)

(5) Angle of valve face

Exhaust valve ... 44 1/4 ± 1/4 degree

Inlet valve ... 29 1/4 ± 1/4 degree

Illustration 2	g00355699

(6) Depth of bore in cylinder head for new valve seat insert ... 13.01 ± 0.38 mm (0.512 ± 0.015 inch)

(7) Diameter of valve seat insert

Exhaust valve ... 42.850 ± 0.013 mm (1.6870 ± 0.0005 inch)

Inlet valve ... 46.025 ± 0.013 mm (1.8120 ± 0.0005 inch)

Bore in cylinder head for valve seat insert

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

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

(8) Angle of face of valve seat insert

Exhaust valve ... 45 1/4 ± 1/2 degrees

Inlet valve ... 30 1/4 ± 1/2 degrees

(9) Valve projection

Maximum permissible projection of the inlet valves and the exhaust valves from the face of the cylinder head ... minus 1.2192 to 0.2032 mm (minus 0.048 to 0.008 inch)

(10) Outside diameter of the face of the valve seat insert

Exhaust seat ... 40.41 ± 0.13 mm (1.591 ± 0.005 inch)

Inlet seat ... 44.04 ± 0.13 mm (1.734 ± 0.005 inch)

(11) Minimum thickness of valve lip

Exhaust valves ... 2.03 mm (0.080 inch)

Inlet valves ... 2.49 mm (0.0980 inch)