3412 Generator Set Engines Caterpillar

Piston Rings

The top two rings are the KEYSTONE rings, which are tapered. A special 1U-6431 Piston Ring Groove Gauge Gp is available to check the top two ring grooves in the piston. Refer to Guideline For Reusable Parts, "Pistons And Cylinder Liners".

Illustration 1	g00365332
Instructions for 1U-6431 Piston Ring Groove Gauge Gp

Connecting Rods and Pistons

Use the 7M-3978 Piston Ring Expander Gp to remove piston rings or install piston rings.

Use the 5P-3526 Piston Ring Compressor to install pistons into the cylinder block.

Tighten the connecting rod nuts in the step sequence that follows:

1. Apply 4C-5593 Anti-Seize Compound to the threads of the bolts and the contact surfaces of the bolt head.

2. Tighten all nuts to the following torque.

   Torque for nuts ... 82 ± 8 N·m (60 ± 6 lb ft)

3. Put an alignment mark on each cap and bolt.

4. Tighten the nuts from the mark to the following value.

   Angle from the mark. ... 120 ± 5 degrees

Connecting Rod Bearings

The connecting rod bearings fit tightly in the bore in the rod. If the bearing joints are fretted, check the bore size. This can be an indication of wear because of a loose fit.

Connecting rod bearings are available with 0.63 mm (0.025 inch) and 1.27 mm (0.050 inch) smaller inside diameter than the original size bearing. These bearings are for crankshafts that have been ground.

Main Bearings

Main bearings are available with a larger outside diameter than the original size bearings. These bearings are used for the cylinder blocks with the main bearing bore that is made larger than the bores' original size. The size that is available has a 0.63 mm (0.025 inch) outside diameter that is larger than the original size bearings. These bearings are available with a standard inside diameter. The bearings are also available with a 0.63 mm (0.025 inch) inside diameter for crankshafts that have been ground.

Main bearings are available with a smaller inside diameter than the original size bearings. These bearings are used for the cylinder blocks with a crankshaft that is made smaller than the crankshaft's original size. The size that is available has a 0.63 mm (0.025) and 1.27 mm (0.050 inch) inside diameter that is smaller than the original size bearings. These main bearings are for crankshafts that have been ground.

Cylinder Block

If the main bearing caps are installed without bearings, the bore in the block for the main bearings can be checked. Tighten the nuts that hold the caps to the torque that is shown in the Specifications, "Cylinder Block". Alignment error in the bores must not be more than 0.08 mm (.003 inch). Refer to Special Instruction, SMHS7606 for instructions on the use of 1P-4000 Line Boring Tool Group .

The 1P-3537 Dial Bore Gauge Group can be used to check the size of the bores. The Special Instruction, GMGO0981 is with the group.

Illustration 2	g00294303
1P-3537 Dial Bore Gauge Group

Projection of Cylinder Liners

Note: The following procedure does not require the use of an "H" bar to hold the liners while the liner projection measurements are taken.

Illustration 3	g01247283
Liner projection components (1) Bolt (2) Washer (3) Washer (4) Spacer plate (5) Block (6) Cylinder liner

Note: The 7K-1977 Washer is made of a cotton fabric that is impregnated with resin. These washers will not damage the sealing surface of the cylinder block. These washers are a disposable item. You may wish to order more washers than the amount that is indicated.

1. Install a new spacer plate gasket and a clean spacer plate.

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Illustration 4	g00365343

2. Install the cylinder liners in the cylinder block without seals or bands.

3. Install the washers. Install the bolts in the holes that are indicated with an "X".

4. Install all bolts or the six bolts around the liner.

   Torque for bolts ... 95 N·m (70 lb ft)

5. Use the 8T-0455 Liner Projection Tool Group to measure the liner projection at "A", "B", "C" and "D".

6. Record measurements for each cylinder.

7. Add the four readings for each cylinder and divide the sum of the readings by four in order to find the average.

Note: If the liner projection changes around the liner, turn the liner to a new position within the bore. If the liner projection is not within specifications, move the liner to a different bore. Inspect the top face of the cylinder block.

The 284-8768 Spacer Plate should be installed, if all the liner projections are below the specifications. The 284-8768 Spacer Plate should also be installed if the liner projection measurements are low in the range. This spacer plate is 0.076 mm (0.003 inch) thinner than the regular plate. This spacer plate will increase the liner projection. Use this spacer plate in order to compensate for low liner projections that are less than 0.076 mm (0.003 inch). Use this spacer plate if the inspection of the top deck reveals no measurable damage directly under the liner flanges but the average liner projection is less than 0.076 mm (0.003 inch).

Do not exceed the maximum liner projection of 0.150 mm (0.006 inch). The excessive liner projection will contribute to cracking of the liner flange.

When the liner projection is correct, put a temporary mark on the liner and the spacer plate. Set the liners aside.

Note: Refer to Disassembly and Assembly, "Cylinder Liner - Install" for the correct final installation procedure for the cylinder liners.

Flywheel and Flywheel Housing

Face Runout (Axial Eccentricity) of the Flywheel Housing

Illustration 5	g00319523
8T-5096 Dial Indicator Group

If you use any other method except the method that is given here, always remember that the bearing clearance must be removed in order to receive the correct measurements.

1. Fasten a dial indicator to the flywheel so the anvil of the dial indicator will contact the face of the flywheel housing.

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Illustration 6	g00294392
Checking face runout of the flywheel housing (A) Bottom (B) Right side (C) Top (D) Left side

2. Put a force on the crankshaft toward the rear before the dial indicator is read at each point.

3. Turn the flywheel while the dial indicator is set at 0.0 mm (.00 inch) at location (A) . Read the dial indicator at locations (B) , (C) and (D) .

4. The difference between the lower measurements and the higher measurements that are performed at all four points must not be more than 0.38 mm (.015 inch), which is the maximum permissible face runout (axial eccentricity) of the flywheel housing.

Bore Runout (Radial Eccentricity) of the Flywheel Housing

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Illustration 7	g00294390
8T-5096 Dial Indicator Group

1. Fasten a dial indicator to the flywheel so the anvil of the dial indicator will contact the bore of the flywheel housing.

2. While the dial indicator is in the position at location (C) adjust the dial indicator to 0.0 mm (.00 inch). Push the crankshaft upward against the top of the bearing. Write the measurement for bearing clearance on line 1 in column (C) .

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Illustration 8	g00294392
Checking face runout of the flywheel housing (A) . (B) . (C) . (D) . (A) Bottom (B) Right side (C) Top (D) Left side

Note: Write the measurements for the dial indicator with the correct notations. This notation is necessary for making the calculations in the chart correctly.

3. Divide the measurement from Step 2 by two. Write this number on line 1 in columns (B) and (D) .

4. Turn the flywheel in order to put the dial indicator at position (A) . Adjust the dial indicator to 0.0 mm (.00 inch).

5. Turn the flywheel counterclockwise in order to put the dial indicator at position (B) . Write the measurements in the chart.

6. Turn the flywheel counterclockwise in order to put the dial indicator at position (C) . Write the measurement in the chart.

7. Turn the flywheel counterclockwise in order to put the dial indicator at position (D) . Write the measurement in the chart.

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Illustration 9	g00294394

8. Add the lines together in each column.

9. Subtract the smaller number from the larger number in column B and column D. Place this number on line III. The result is the horizontal eccentricity (out of round). Line III in column C is the vertical eccentricity.

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Illustration 10	g00294396
Graph for total eccentricity (1) Total vertical eccentricity (2) Total horizontal eccentricity (3) Acceptable value (4) Unacceptable value

10. On the graph for total eccentricity, find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

11. If the point of the intersection is in the "Acceptable" range, the bore is in alignment. If the point of intersection is in the "Unacceptable" range , the flywheel housing must be changed.

Face Runout (Axial Eccentricity) of the Flywheel

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Illustration 11	g00294398
Checking face runout of the flywheel

1. Refer to Illustration 11 and install the dial indicator. Always put a force on the crankshaft in the same direction before the dial indicator is read. This will remove any crankshaft end clearance.

2. Set the dial indicator to read 0.0 mm (.00 inch).

3. Turn the flywheel at intervals of 90 degrees and read the dial indicator.

4. Take the measurements at all four points. Find the difference between the lower measurements and the higher measurements. This value must not exceed the maximum permissible face runout (axial eccentricity) of the flywheel. The maximum permissible face runout is 0.15 mm (0.006 inch).

Bore Runout (Radial Eccentricity) of the Flywheel

Illustration 12	g01253418
Checking bore runout of the flywheel (1) 7H-1945 Holding Rod (2) 7H-1645 Holding Rod (3) 7H-1942 Dial Indicator (4) 7H-1940 Universal Attachment

1. Install the 7H-1942 Dial Indicator (3) . Make an adjustment of the 7H-1940 Universal Attachment (4) so that the dial indicator makes contact on the flywheel.

2. Set the dial indicator to read 0.0 mm (.00 inch).

3. Turn the flywheel at intervals of 90 degrees and read the dial indicator.

4. Take the measurements at all four points. Find the difference between the lower measurements and the higher measurements. This value must not exceed the maximum permissible bore runout (radial eccentricity) of the flywheel.

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Illustration 13	g00294401
Flywheel clutch pilot bearing bore

5. Take the measurements at all four points. Find the difference between the lower measurements and the higher measurements. This value must not exceed the maximum permissible pilot bore runout of the flywheel.

Vibration Damper

Illustration 14	g00367672

Damage to the vibration damper or failure of the vibration damper will increase vibrations. This will result in damage to the crankshaft.

Replace the vibration damper if the vibration damper is bent or if the vibration damper is damaged. Replace the vibration damper if the bolt holes are oversize. Replacement of the vibration damper is also needed at the time of a crankshaft failure due to torsional forces.