3508 Marine Engine 96Y00683-UP(SEBP1553 - 21) - Document Structure Page 1 of 8

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Product: MARINE ENGINE

Disassembly and Assembly

Camshafts
SMCS - 1210-011

Remove Camshafts

Start By:

a. remove rocker shaft assemblies and push rods

b. remove crankcase breathers (left side only)

c. remove tachometer drive (right side only)

d. remove governor (right side only)

1. Remove access covers (1) from the sides of the engine.

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2. Remove bolt (3) and cap (4) that hold fuel rod assembly (2) to the fuel control shaft.

3. Remove bolts (5) to remove lever assembly (6) and fuel rod assembly (2) as a unit from the cylinder heads. If
necessary, use tool (A) to turn the flywheel until the camshaft is moved in a position so that the fuel rod assembly can be
removed between the engine block and camshaft.

4. Remove cover (7) from the left side of the flywheel housing.

5. Remove the bolts, and remove plate (8) from the end of the camshaft on the left side of the engine.

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NOTICE
Use the 8B7561 Step Plate of Tooling (B) to prevent damage to the end of the
camshaft during removal of drive gear (9).

6. Use tooling (B) to remove drive gear (9) from the end of the camshaft on each side of the engine. Remove the drive
gears from the flywheel housing.

7. Remove the bolts, and remove washer (10) from he end of the camshaft on each side of the engine.

8. Push valve lifters (11) up away from the camshaft into the cylinder head assemblies, and hold the lifters in this
position. An O-ring seal can be used to hold the valve lifters up.

9. Install the pilot assembly part of tool group (C) on one end of the camshaft.

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10. Install the handle part of tool group (C) on the other end of the camshaft.

11. Pull camshaft (12) out of the engine block until a hoist can be fastened to it.

12. Put identification marks on the camshafts as to their location in the engine so they can be installed correctly.

13. Remove camshaft (12) and tool group (C) from the engine. The weight of the camshaft used in 3512 Engines is 63 kg
(139 lb.). The weight of a camshaft used in a 3516 Engine is 82 kg (181 lb.).

14. If necessary, remove bolts (13) to make a separation of the 3512 Camshaft and the 3516 Camshaft.

Install Camshafts

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1. If the 3512 Camshafts and 3516 Camshafts were taken apart, make sure spacer (2) is in position between the camshaft
and camshaft assembly. Put 9S3263 Thread Lock on the threads of bolts (1), and tighten the bolt by hand only to a
torque of 45 ± 7 N·m (33 ± 5 lb.ft.).

NOTE: Make sure the camshafts are installed respective to the marks (Rear L.H., Rear R.H.) on the ends of the
camshafts.

2. Install the pilot assembly part of tool group (A) to one end of the camshaft and the handle part of tool group (A) to the
other end.

3. Fasten a hoist to camshaft (3), and put it in position. Push it into the engine block. Remove the hoist and tool group
(A).

4. Install washers (4) on each side of the engine to hold the camshafts in position.

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5. Remove timing pins (5) from their storage positions on each side of the engine.

6. Turn the camshafts until timing pins (5) can be installed through the cylinder block and into the grooves (slots) in the
camshafts.

7. Remove cover (6) and plug (7) from the right front side of the flywheel housing.

8. Put timing bolt (8) in position in the flywheel housing. Use tool (B) and a ratchet wrench to turn the flywheel until the
timing pin engages with the hole in the flywheel. The No. 1 cylinder is now at top center.

9. Put drive gears (9) in position on the end of the camshaft on each side. (For correct timing, all gear clearance
(backlash) must be removed. Turn drive gears (9) in the same direction as crankshaft rotation and hold this
position.)

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10. Install plate (11) and the bolts to hold the drive gear to the camshaft. Tighten the bolts evenly to a torque of 100 ± 15
N·m (74 ± 11 lb.ft.). Hit the plate with a hammer, and tighten the bolts again to the same torque. Do this until the
torque does not change.

11. Install the gasket and cover (10) over the camshaft.

12. Install the tachometer drive adapter on the other camshaft to hold the drive gear in position. See Install Tachometer
Drive.

13. Remove the timing pins for the camshaft, and install the pins in their storage positions.

14. Remove the timing bolt from the flywheel, and install the plug in the timing hole in the housing. Remove tool (B),
and install the cover on the housing.

15. Remove the O-ring seals from valve lifters (12), and push the lifters down against the camshaft.

16. Install fuel rod assembly (14) and lever assembly (13) as a unit in the cylinder head assemblies. If necessary, use tool
(B) to turn the flywheel until camshafts move enough to permit the fuel rod assembly to move into position.

17. Make sure lever assembly (13) is engaged correctly with the fuel injection pump rack, and install the bolts.

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18. Install the bolt and cap (15) to hold the fuel rod assembly to the fuel control shaft.

19. Install access covers (16) on each side of the engine.

20. See Testing And Adjusting section for the correct adjustment of the fuel injection control group.

End By:

a. install governor (right side only)

b. install crankcase breather (left side only)

c. install rocker shaft assemblies and push rods

d. install tachometer drive (right side only)

Copyright 1993 - 2006 Caterpillar Inc. Tue Nov 14 13:17:21 UTC+0700 2006
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