C-15 Truck Engine Caterpillar

Dual Springs

Illustration 1	g00645577

Note: Apply 8T-2998 Lubricant to the valve stems prior to installation in the cylinder head.

(1) Valve springs

175-7523 Spring (Inner)

Assembled length ... 60.14 mm (2.368 inch)

Load at assembled length ... 118 ± 12 N (27 ± 3 lb)

Operating length (minimum) ... 44.02 mm (1.733 inch)

Load at minimum operating length ... 356 ± 18 N (80 ± 4 lb)

Free length after test ... 71.03 mm (2.797 inch)

Outside diameter ... 25.20 mm (0.992 inch)

175-7526 Spring (Outer)

Assembled length ... 67.12 mm (2.643 inch)

Load at assembled length ... 248 ± 25 N (56 ± 6 lb)

Operating length (minimum) ... 51.00 mm (2.008 inch)

Load at minimum operating length ... 736 ± 35 N (165 ± 8 lb)

Free length after test ... 77.88 mm (3.066 inch)

Outside diameter ... 36.30 mm (1.429 inch)

(2) Valve guide

Bore of installed valve guide (new parts) ... 9.487 ± 0.025 mm (0.3735 ± 0.0010 inch)

Maximum recommended diameter of the valve guide bore ... 9.538 mm (0.3755 inch)

Note: Do not use a combination of a valve and a valve guide that has a difference of 0.13 mm (0.005 inch) or more.

(3) Height to top of valve guide ... 35.00 ± 0.50 mm (1.378 ± 0.020 inch)

(4) Valve recess

Inlet (new parts) ... 2.20 to 2.80 mm (0.087 to 0.110 inch)

Exhaust (new parts) ... 1.20 to 1.80 mm (0.047 to 0.071 inch)

Inlet (reconditioned parts) ... 2.20 to 3.29 mm (0.087 to 0.129 inch)

Exhaust (reconditioned parts) ... 1.20 to 2.29 mm (0.0472 to 0.090 inch)

Illustration 2	g00640401
153-7023 Inlet Valve and 153-7024 Exhaust Valve

(5) Valve face angle

Inlet ... 29 1/4 ± 1/4 degrees

Exhaust ... 44 1/4 ± 1/4 degrees

(6) Valve stem diameter

New valve stem diameter ... 9.441 ± 0.010 mm (0.3717 ± 0.0004 inch)

Minimum recommended valve stem diameter ... 9.408 mm (0.3704 inch)

(7) Diameter of valve head

Inlet ... 47.00 ± 0.13 mm (1.850 ± 0.005 inch)

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

(8) Minimum recommended valve lip thickness

Inlet ... 2.75 mm (0.108 inch)

Exhaust ... 2.05 mm (0.081 inch)

(9) Overall length of valve

Inlet ... 202.00 ± 0.45 mm (7.953 ± 0.018 inch)

Exhaust ... 202.06 ± 0.45 mm (7.955 ± 0.018 inch)

Illustration 3	g00564825
156-4168 Valve Seat (Inlet) and 152-7582 Valve Seat (Exhaust)

(10) Minimum recommended width of the valve seat

Inlet ... 2.00 mm (0.079 inch)

Exhaust ... 1.25 mm (0.049 inch)

(11) Depth of bore in the cylinder head for the valve seat insert

Inlet ... 14.00 ± 0.10 mm (0.551 ± 0.004 inch)

Exhaust ... 13.90 ± 0.10 mm (0.547 ± 0.004 inch)

(12) Inside diameter of valve seat insert

Inlet ... 41.00 ± 0.50 mm (1.614 ± 0.020 inch)

Exhaust ... 36.50 ± 0.50 mm (1.437 ± 0.020 inch)

(13) Angle of valve seat face

Inlet ... 30 1/4 ± 1/2 degrees

Exhaust ... 45 1/4 ± 1/2 degrees

(14) Outside diameter of valve seat insert

Inlet ... 48.025 ± 0.013 mm (1.8907 ± 0.0005 inch)

Exhaust ... 42.840 ± 0.013 mm (1.6866 ± 0.0005 inch)

Diameter of the bore in the cylinder head for the valve seat insert

Inlet ... 47.950 ± 0.025 mm (1.8878 ± 0.0010 inch)

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