Alignment Procedure for G3500 Tandem Generator Sets{4450} Caterpillar

Alignment Procedure for G3500 Tandem Generator Sets{4450}

Usage:

Engine:: G3512 (S/N: 7NJ1-UP); G3516 (S/N: 8LD1-UP; 4EK1-UP); G3516B (S/N: 7EZ1-UP); G3524 (S/N: 7SZ1-UP); G3532 (S/N: 8BZ1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you have read this information and you understand this information.

This Special Instruction describes the alignment procedure for G3500 Engines with the close coupled type of two-bearing generators. Proper alignment is necessary for maximum performance and for service life for the generator set. The package is aligned in an engine-engine-generator configuration.

This Special Instruction provides the necessary instructions for the preparation of the alignment. The required equipment for measurements is identified. The dimensions and tolerances for the alignment are also provided. A sequence of steps is provided for alignment.

Alignment of the Close Coupled Two-Bearing Tandem Generator Sets

It will be necessary to review the composition of the complete installation. When the weight of any attachment or fluid compartment exceeds 225 kg (500 lb), it will be necessary to fill the compartment before you proceed with the alignment. You may also use an object with the appropriate weight to simulate the fluid's weight.

Mounting the Engines

Note: Step 1 and Step 2 are only necessary when you are removing and remounting the engines. If the unit is dowelled, the old dowels will need to be removed. Drill new dowel holes and install new dowels after the final alignment.

Note: The rear engine is the engine that is closest to the load. The front engine is the engine that is farthest away from the load.

Place the front engine on the base to the dimensions that are provided in the mounting group. Center the engine on the base. This is done by measuring the dimensions from the edge of the base to either side of the engine block.

Place the rear engine on the base. Use 6.35 mm (0.25 inch) plates in order to shim the engine.

Installing a New Flexible Coupling on the Front Engine

Assemble the front engine's coupling according to the flexible coupling assembly. Install the inner coupling with one of the 7/8 inch tapped holes in line with the dash mark on the crankshaft and on the flywheel. Do not fill the coupling with the viscous silicon compound at this time.

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Illustration 1	g01311188
(1) Front face of the cylinder block of the engine that is closest to the load (2) Rear face of the cylinder block of the engine that is farthest from the load (3) Camshaft timing hole (4) Storage position of the camshaft timing pin (5) Camshaft cover (6) Hole for the pinion (7) 1 inch bolt (8) 7/8 inch bolt (9) Spacer assembly (10) End clearance of the coupling (A) Position of the dial indicator for measuring the shaft's runout (B) Position of the dial indicator for measuring the alignment of the front engine and the rear engine (C) Position of the dial indicator for measuring the alignment of the front engine and the rear engine

Install the coupling shaft to the rear engine by aligning the dash marks of the crankshaft, the damper, the adapter, and the coupling shaft. Tighten 1 inch bolts (7) .
Tightening procedure for the 1 inch bolts
Lubricate the face of the washers and the threads of the bolts with anti-seize compound.
Tighten the bolts in a star pattern. ... 50 N·m (37 lb ft)
Tighten the bolts again in a star pattern. ... 400 ± 50 N·m (295 ± 37 lb ft)

Note: Additional tightening is needed for the 1 inch bolts, but the shaft's runout must be checked first.

Place a dial indicator on position (A) that is shown in Illustration 1. Support the dial indicator from a stationary position above the shaft. Zero the dial indicator.

Rotate the crankshaft with a barring device. Measure the total indicator reading. The maximum total indicator reading of the shaft's runout is 0.25 mm (0.010 inch).
If the shaft's runout is within the specification, tighten the 1 inch bolts in a star pattern for an additional 180 ± 15 degrees.
If the shaft's runout exceeds 0.25 mm (0.010 inch), note the total indicator reading. Use the following procedure.
1. Rotate the shaft to the surface's lowest position. Loosen all twelve 1 inch bolts.
1. Use a hydraulic jack in order to lift the shaft for 1/2 of the previous total indicator reading. Tighten the 1 inch bolts.
  Tightening procedure for the 1 inch bolts
  
  Tighten the bolts in a star pattern. ... 50 N·m (37 lb ft)
  Tighten the bolts again in a star pattern. ... 400 ± 50 N·m (295 ± 37 lb ft)
1. Remove the hydraulic jack. Measure the shaft's runout again.
  If the shaft's runout is within the specification, tighten the 1 inch bolts in a star pattern for an additional 180 ± 15 degrees.
  If the runout is still greater than 0.25 mm (0.010 inch), inspect the shaft for dimensional conformance.

Place rear engine's number one piston at the top center position. For instructions, refer to the engine's Systems Operation/Testing and Adjusting manual.
After the rear engine's number one piston is at the top center position, do not rotate the crankshaft until both engines are coupled together.
Note: The engines are timed in the factory. The marks on the engines' coupling shaft and the marks on the flexible coupling must be aligned in order to ensure proper reassembly.

Place front engine's number one piston at the top center position. For instructions, refer to the engine's Systems Operation/Testing and Adjusting manual.

Mark the front engine's flywheel at a point that is adjacent to a flywheel housing bolt hole and rotate the crankshaft according to the engine model.
Note: The bolt holes for the G3516 Engine flywheel housing are separated by 22.5 degrees. The flywheel mark will be two bolt holes short of one revolution when the G3516 Engine is timed.
For the G3516 Engine, rotate the crankshaft for 315 degrees in the direction of normal rotation.
For the G3512 Engine, rotate the crankshaft for 360 degrees in the direction of normal rotation.
The front engine is now timed and ready to be coupled.

Refer to the flexible coupling assembly for additional information on coupling the engines together. Install two full containers of the silicon compound into the coupling.

Move the engines into position in order to be coupled.

If spacer assembly (9) is not assembled, assemble the spacer assembly. Refer to Illustration 1.
Tighten the spacer assembly's 3/8 inch bolt to a torque of 45 ± 7 N·m (35 ± 5 lb ft).

Install 7/8 inch bolts (8). Lubricate the bolt threads and the washers with engine oil. Tighten the bolts to a torque of 750 ± 80 N·m (555 ± 60 lb ft).

Set the end clearance of the inner coupling to 10.4 ± 0.8 mm (0.41 ± 0.03 inch). Refer to item (10) in Illustration 1.
The end clearance is set by first loosening the bolts in the block of the rear engine. Use the lugs that are welded to the base in order to set the clearance. Then tighten the bolts.
After the end clearance of the inner coupling is set, the timing and the coupling is complete. The generator set can now be rotated for final alignment.

Installing a New Flexible Coupling on the Rear Engine

Once the engines are timed, coupled, and aligned, the generator can be mounted and aligned.

Assemble the coupling to the rear engine. Refer to the flexible coupling assembly.

Before you install the generator, ensure that the feet and the mounting holes are clean and ensure that the feet and the mounting holes do not have any grease, paint, rust, or dirt.

Use a crane to move the generator close to the rear engine. Begin threading the bolts that hold the close coupled adapter to the engine's flywheel housing. Bring the generator tightly against the engine. Tighten the generator's hub lock bolts finger tight.

Insert an initial shim pack between the mounting blocks and the generator mounts. Insert as many shims as necessary.

Final Alignment of the Front Engine to the Rear Engine

Complete the final alignment with a laser alignment tool. If a laser alignment tool is not available, use a dial indicator to measure the alignment. If you are using a laser alignment tool for the final alignment, refer to Step 1.a. If you are using a dial indicator for the final alignment, refer to Step 1.b.

Use Table 1 for the final alignment. Tighten all bolts to the specified torques. After the alignment is complete, attach all protective guards.

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Table 1
Vertical (mm)	Horizontal (mm)	Vertical Angle (mm / 100 mm Dia)	Horizontal Angle (mm/100 mm Dia)
0.0 ± 0.1	0.0 ± 0.1	0.0 ± 0.02	0.0 ± 0.02
Vertical (mils)	Horizontal (mils)	Vertical Angle (mils/10 inch Dia)	Horizontal Angle (mils/10 inch Dia)
0 ± 4	0 ± 4	0 ± 2	0 ± 2

Note: If you are using the dial indicators to measure alignment, use caution in the interpretation of the measurements, in the compensation of the axial shaft end play, and in the proper support bracket.

Attach an indicator stem to the shaft in order to support the indicators at position (B) and at position (C). Refer to Illustration 1. Rotate the engines and observe the dial indicators at four positions. A pinch bar may be used in order to remove the end play in both of the crankshafts before taking the readings. Align the engines so that the radial total indicator reading is not more than 0.20 mm (0.008 inch). Tighten all of the bolts to the specified torques. After the alignment is complete, attach all protective guards.

Alignment of the Rear Engine to the Generator

Tighten the 1 inch generator mounting bolts to half of the standard torque. The standard torque is 900 N·m (660 lb ft). Loosen the bolts in the flywheel housing. Visually ensure that all 16 bolts are centered within the clearance holes in the close coupled adapter.
To compensate for the bolts that are not centered in the holes, shims may be added or removed from the generator mounts.

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Illustration 2	g00456859
(D) Flywheel housing (E) Close coupled adapter (F) Engine (G) Generator

While the 16 close coupled adapter bolts are loose, use a feeler gauge to check the gap between flywheel housing (D) and adapter (E). Measure the gap at the 2 o'clock, 4 o'clock, 8 o'clock, and 10 o'clock positions.
The minimum clearance is 0.025 mm (0.001 inch).
The maximum clearance is 0.127 mm (0.005 inch).

If the gap is not within the specifications, loosen the generator mounting bolts. Add or remove the appropriate amount of shims. Repeat Step 1 and Step 2 until the desired gap is achieved.