BELT TENSIONER 3779082 - Caterpillar

All Caterpillar EnginesAll current Caterpillar engines can be line bored using the 1P4000 Line Boring Tool Group. The 1100, 3100 and 3208 Service Manuals contain line boring instructions for those engines. Centering rings are available for both original and oversize main bearings. Part numbers and sizes are given on pages 2 and 3. Additional information for non-current engines is given in the back of this instruction. 1 Clean all of the bearing caps and saddles and remove all nicks from pan rail (1). Apply layout bluing to the bearings and caps that are to be bored. Plug oil holes (2) in the block with grease to prevent metal chips from entering the oil passages. 2 The original size centering rings given above are not included in the tool group. Two rings are required for each engine. The dimensions given are the true main bearing bore sizes for each engine, and they are stamped on each ring. The diameter of the ring itself is approximately .0005" (0.0127) less than this dimension. Centering rings given above are for use in oversize main bearing bores. All of these centering rings are for .025" (0.64) oversize main bearing bores, except the 6V138 Centering Ring. The 6V138 Centering Ring is for use in .010" (0.25) oversize main bearing bores. 3 To initially set the micrometer in the bracket assembly, measure the diameter of any centering ring (3) with an outside micrometer that is known to be accurate, and set micrometer (4) to the exact dimension of the ring. Place the ring on the fixture and push the micrometer until spindle (5) lightly touches the ring, then tighten bolt (6). Back off the micrometer thimble and recheck. Repeat the above steps until the micrometer reading is accurate. 4 Place centering rings (3) on each side of the caps that are being replaced.5 To bore an end cap, place centering rings (3) in the second and fourth main bearing bores. 6 Place the unbored new caps (7) on the block with the part number on the same side as the originals. Stamp each new cap to correspond with the number stamped on the pan rail. Tighten the cap nuts as specified in the Service Manual. Place the original bearing caps over centering rings (3), but do not tighten the nuts. 7 Oil boring bar (8) and insert it through the centering rings. Tighten the caps to a torque of 10-20 lb. ft. (14-25) minimum while spinning the bar to check for binding. The centering rings must be seated securely in the bearing saddles after tightening. 8 Bearing assembly (9) and bridge (10) are used when the centering rings do not provide sufficient support for the boring bar; place bearing assembly (9) on the bar, adjust the bearing by tightening bolt (11) until the bar begins to bind, then back off until the bar spins easily. 9 When boring an end cap, place a bridge on the opposite end of the block. When boring