CHAIN GP-BOOM 2039411 - Caterpillar

Alignment Of Front Power Take-Off Groups
Correct alignment of the new front power take-off groups is very important. The new groups' alignment is controlled by the runout (full indicator movement or total indicator reading) of the adapter and bore-to-crankshaft center line, and the runout of the housing pilot and face in relation to the clutch shaft center line. Since the factory tolerances control the alignment of the parts, they control the alignment of the front power take-off group with the crankshaft. Correct installation prevents alignment changes.
The earlier groups' alignment was controlled by either the pilot or external bearing.
It is Caterpillar's recommendation that the steps which follow be used during installation, to make sure the front power take-off group is in correct alignment with the engine. If the front power take-off group was a separate purchase and did not come installed on the engine, begin with Step 1. If the front power take-off group came as an installed attachment, begin with Step 6.
1. With the engine installed in the boat, install the 5N7751 Adapter with eight S1573 Bolts tightened to a torque value of 115 15 N m (85 11 lb ft) and install the 3L8029 or 4B4805 Drive Ring with eight S1591 Bolts.2. Put a dial indicator in position to read the total vertical movement of the crankshaft at the top of the drive ring. Use a lever to move the drive ring and crankshaft upward and read the indicator total movement. Do not put force against the adapter housing because it will move the dial indicator base.
Do not use any more force than is necessary to move the crankshaft.
3. Fasten the base for the dial indicator to the drive ring. Put the indicator in position to read the runout of the adapter bore. Turn the crankshaft and write the indications for 0°, 90°, 180° and 270°. Add one-half the indication from Step 2 to the 0° indication and subtract one-half the indication from Step 2 from the indication at 180°. With the adjusted values at 0° and 180°, there must not be more than 0.36 mm (.014") difference between any two of the four points measured.4. With the base still fastened to the drive ring, move the dial indicator to read the face edge of the adapter. Turn the crankshaft and read the runout. The runout must not be more than 0.41 mm (.016").5. If Steps 3 and 4 are not in an acceptable specification range, loosen the bolts and adapter, and tighten the bolts again, to 115 15 N m (85 11 lb ft). Do Steps 3 and 4 again. If the indications still are not acceptable, replace the adapter and/or drive ring. If the indications are acceptable, install the remainder of the group, including the 5N6958 Channel.6. Fabricate and install the structure to which the 5N6958 Channel will be fastened. It is best to make the structure no more than 6.35 mm (.25") lower than the channel.7. Put a dial indicator under