MANIFOLD-AIR INLET 1883085 - Caterpillar

(1) Gear. If new gear is required, replace camshaft assembly. The heat treatment of the gear is damaged if heated.(2) Diameter of the surfaces (journals) for the camshaft bearings (new) ... 69.850 0.013 mm (2.7500 .0005 in) Bore in front bearing for the camshaft (after assembly) ... 69.969 0.048 mm (2.7547 .0019 in)Bore in the other six bearings for the camshaft (after assembly) ... 69.982 0.061 mm (2.7552 .0024 in)(3) Thickness of thrust plate (new) ... 4.65 0.03 mm (.183 .001 in) End play of the camshaft ... 0.10 to 0.26 mm (.004 to .010 in)(4) Camshaft. (5) Height of camshaft lobes.To find lobe height, use the procedure that follows:A. Measure camshaft lobe height (5).B. Measure base circle (7).C. Subtract base circle (STEP B) from lobe height (STEP A). The difference is actual lobe lift (6).D. Specified camshaft lobe lift (6) is: 8N9245 Camshaft Assemblya. Exhaust lobe ... 8.100 mm (.3189 in)b. Intake lobe ... 8.783 mm (.3458 in) 100-7408 Camshaft Assemblya. Exhaust lobe ... 10.210 mm (.4019 in)b. Intake lobe ... 10.212 mm (.4021 in)Maximum permissible difference between actual lobe lift (STEP C) and specified lobe lift (STEP D) is 0.13 mm (.005 in).Intake Valve Timing
1. Check the No. 1 intake valve lash with the engine stopped. The valve lash must be 0.30 to 0.46 mm (.012 to .018 in). If the valve lash is not in this range, adjust the lash to 0.38 mm (.015 in).2. Mark Top Center Position of the crankshaft on the vibration damper or pulley.3. Use a dial indicator to measure the intake valve movement.4. Rotate the crankshaft in the direction of normal engine rotation. Stop when the intake valve is 1.91 mm (.075 in) off its seat in the opening sequence.At this point the crankshaft Top Center Position Mark must be in position as follows: Engines with the 8N9245 Camshaft Assembly ... 3 2 degrees After Top CenterEngines with the 100-7408 Camshaft Assembly ... 1 2 degrees After Top Center