Usage:
(14)Governor
- 1. Remove tachometer drive cable (or cap) from the tachometer drive housing, and install an accurate tachometer.
This adjustment should be made by an authorized dealer.
- 2. See the Engine Specifications Chart for high and low idle settings.
(15)Air Fuel Ratio Control
Slow engine response and low power may indicate a need for repair or adjustment by your Caterpillar dealer.
(16)Engine Valve Lash
Adjust valves with the engine stopped and cold.
If valve clearance is within ± .003 inch (0.07 mm) of the clearance given, adjustment is not required. If clearance is not within these limits, adjust the valves.
There are two rocker arms (A), per cylinder. One rocker arm for the two exhaust valves and one rocker arm for the two inlet valves. Each pair of valves is connected by a bridge (B), which is actuated by the rocker arm. The valves in each pair are adjusted simultaneously by the adjusting screw (C), in the rocker arm. Each bridge is adjusted by adjusting screw (D).
- 1. Remove the flywheel housing timing hole cover (A).
- 2. Remove the plug (B).
- 3. Rotate the flywheel in direction of engine rotation.
The engine can best be rotated by removing the flywheel housing timing hole cover and installing an engine turning tool, Caterpillar Part Number 9S9082. Contact your authorized dealer for information.
- 4. Install the timing bolt in the flywheel. This is the top bolt of the two bolts that secure the flywheel housing cover.
- 5. Clean the area around the valve cover. Remove the cover.
- 6. Determine if No. 1 or No. 6 piston is on compression stroke. The cylinder on compression will have both the inlet and exhaust valves closed.
Bridge Adjustment
Adjustment of the bridge will be necessary only after grinding the valves or other reconditioning of the cylinder head is done. Make an adjustment to the bridge using the following procedure.
Valves must be fully closed.
If the bridge was removed perform steps 1 and 2 that follow. If bridge was not removed, proceed to step 3.
- 1. Put engine oil on the bridge dowel in the cylinder head and in the bore in the bridge.
- 2. Install the bridge with the adjustment screw toward the exhaust manifold.
- 3. Back off adjusting screw several turns (counterclockwise), making sure it is not in contact with the valve stem.
- 4. Firmly press straight down on the rocker arm above point of contact with bridge.
- 5. Turn the adjusting screw clockwise until contact is made with the valve stem. Turn the adjusting screw an additional 30° (one-twelfth turn).
- 6. Hold the adjusting screw in this position and tighten the locknut to 22 ± 3 lb. ft. (30 ± 4 N·m).
- 7. Put engine oil at the point where the rocker arm makes contact with the bridge.
After checking the bridge adjustment, make the valve lash adjustment.
Valve Lash Adjustment:
- 1. With No. 1 piston at TDC on compression, check lash between the bridge and rocker arm on exhaust valves of cylinders 1, 3, 4, and 8 and inlet valves for cylinders 1, 2, 5, and 7.
- 2. To adjust, loosen valve adjusting lock nut and turn adjusting screw to allow proper size feeler gauge to pass between top of bridge and the valve rocker arm.
- 3. Set lash at .015 (0.38 mm) for inlet valves and .030 (0.76 mm) for exhaust valves.
- 4. Tighten adjusting screw locknut and check lash.
- 5. Turn flywheel 360° in direction of engine rotation. Align flywheel timing bolt with the timing hole in the flywheel. No. 6 cylinder will be at TDC compression stroke (valves closed).
- 6. Check lash between the bridge and rocker arm on exhaust valves for cylinders 2, 5, 6, and 7 and inlet valves for cylinders 3, 4, 6, and 8. Adjust valves if necessary.