C-10 and C-12 Truck Engines Caterpillar

Illustration 1	g01436825
(3) Key (4) Gear

(1) Torque for thrust pin ... 28 ± 7 N·m (20 ± 5 lb ft)

(2) Diameter of new camshaft journals ... 74.850 ± 0.025 mm (2.9468 ± .0010 inch)

Illustration 2	g01436826
(A) Camshaft lobe lift (B) Camshaft lobe height (C) Base circle

(A) Camshaft lobe lift

Specified camshaft lobe lift (A)

Exhaust lobe ... 9.550 mm (.3760 inch)

Inlet lobe ... 11.371 mm (.4477 inch)

Injector lobe ... 11.275 mm (.4439 inch)

Specified base circle (C)

Exhaust lobe ... 55.0 ± 0.4 mm (2.17 ± .02 inch)

Inlet lobe ... 51.0 ± 0.4 mm (2.01 ± .02 inch)

Injector lobe ... 51.0 ± .4 mm (2.01 ± .02 inch)

To find the lobe lift, use the procedure that follows:

1. Measure the camshaft lobe height (B).

2. Measure the base circle (C).

3. Subtract the base circle that is found in Step 2 from the lobe height that is found in Step 1. The difference is the actual camshaft lobe lift (A).

Maximum permissible difference between actual lobe lift and the specified lobe lift of a new camshaft ... ± 0.13 mm (.005 inch)