C7 Industrial Engines Specifications – Cylinder Head Valves

(1) Exhaust valve

(2) Inlet valve

Note: The inlet and exhaust valve stems must be coated with clean unused engine oil prior to installation in the cylinder head.

Note: The tips of the inlet and exhaust valves must be coated with 8T-2998 Lubricant . The lubricant must be applied after assembly of the retainer.

(3) 137-6718 Spring

Length under test force … 80.27 mm (3.160 inch)
Test force … 662 ± 33 N (150 ± 7.4 lb)
Free length after test … 92.08 mm (3.625 inch)
Outside diameter … 28.82 mm (1.135 inch)
(4) 140-6188 Spring

Length under test force … 60.4 mm (2.38 inch)
Test force … 302.5 ± 18.0 N (68.0 ± 4.0 lb)
Free length after test … 67.5 mm (2.66 inch)
Outside diameter … 28.6 mm (1.13 inch)
(5) Valve guide

Outside diameter of new valve guides

Inlet valve guides … 13.030 ± 0.008 mm (0.5130 ± 0.0003 inch)
Exhaust valve guides … 16.000 ± 0.008 mm (0.6299 ± 0.0003 inch)
Diameter of new valve guide bore

Inlet valve guides … 8.072 ± 0.013 mm (0.3178 ± 0.0005 inch)
Exhaust valve guides … 9.512 ± 0.013 mm (0.3745 ± 0.0005 inch)
Note: Install the valve guide from the spring side of the cylinder head. Check the diameter of the valve guide bore for distortion after installation into the cylinder head.

(6) Diameter of new valve stems

Inlet valve stems … 8.000 ± 0.008 mm (0.3150 ± 0.0003 inch)
Exhaust valve stems … 9.441 ± 0.010 mm (0.3717 ± 0.0004 inch)
Note: The inlet valves and exhaust valves may be reused if the valve stems are not greater than the minimum diameters.

Minimum diameter of a valve stem that is worn

Inlet valve stems … 7.965 mm (0.3136 inch)
Exhaust valve stems … 9.408 mm (0.3704 inch)
(A) Height to the top of the valve guides after installation

Inlet valve guides … 23.0 ± 0.5 mm (0.91 ± 0.02 inch)
Exhaust valve guides … 17.8 ± 0.5 mm (0.70 ± 0.02 inch)
Note: After you press the valve guide into the cylinder head, install the seal onto the top of the valve guide.

Note: The inlet valve guides and the exhaust valve guides can be reused if the valve guide bores are not greater than the maximum diameters.

Maximum diameter of a valve guide bore that is worn

Bore of inlet valve guide … 8.080 mm (0.3181 inch)
Bore of exhaust valve guide … 9.538 mm (0.3755 inch)
(B) Diameter of the head of the valve for new valves

Inlet valve head … 40.00 ± 0.13 mm (1.575 ± 0.005 inch)
Exhaust valve head … 43.00 ± 0.13 mm (1.693 ± 0.005 inch)
(C) Angle of the valve faces for new valves

Inlet valve face … 29.75 ± 0.25 degrees
Exhaust valve face … 45.0 ± 0.25 degrees

(D) External diameter of the valve seat inserts

Inlet valve seat insert … 42.000 ± 0.013 mm (1.6535 ± 0.0005 inch)
Exhaust valve seat insert … 46.000 ± 0.013 mm (1.8110 ± 0.0005 inch)
Diameter of the bore in cylinder head for the valve seat insert

Bore diameter for the valve seat inserts

Inlet valve seat insert … 41.931 ± 0.013 mm (1.6508 ± 0.0005 inch)
Exhaust valve seat insert … 45.931 ± 0.013 mm (1.8083 ± 0.0005 inch)
Note: The valve seat insert must be shrunk by reduced temperature before the valve seat insert is installed in the head.

(E) Depth of the bore that is machined into the cylinder head for the valve seat insert

Inlet valve seat insert … 9.00 ± 0.05 mm (0.354 ± 0.002 inch)
Exhaust valve seat insert … 10.00 ± 0.05 mm (0.394 ± 0.002 inch)
(F) Angle of the valve seat that is ground into the valve seat inserts

Inlet valve seat insert … 30.25 ± 0.25 degrees
Exhaust valve seat insert … 45.50 ± 0.25 degrees
Note: Do not reuse the valve seat inserts if the outside diameter of the valve seat is larger than the following values.

(G) Outside diameter of the valve seat that is ground into the face of the valve seat insert

Inlet valve seat insert … 37.351 mm (1.4705 inch)
Exhaust valve seat insert … 40.800 mm (1.6063 inch)
Note: The inlet valves and the exhaust valves can be reused if the valve lips are not smaller than the minimum dimensions.

(H) Minimum dimensions for the valve lips

Inlet valve … 2.04 mm (0.080 inch)
Exhaust valve … 1.63 mm (0.064 inch)
(J) Distance from the head of the valve to the face of the cylinder head

Inlet valve

Maximum permissible distance … 1.71 mm (0.067 inch)
Minimum permissible distance … 1.09 mm (0.043 inch)
Exhaust valve

Maximum permissible distance … 1.71 mm (0.067 inch)
Minimum permissible distance … 1.09 mm (0.043 inch)
Note: Ensure that the valve is fully closed in order to measure this value.