Alignment Of Caterpillar Diesel Engines To Caterpillar Marine Transmission (7271-36W){1000, 3300} Caterpillar

This instruction gives the procedure to put the above engines in alignment with and connect them to 7271 Caterpillar Marine Transmissions. Two types of flexible couplings are used to connect the engine to the transmission: 8N8872 Coupling Group uses ten rubber blocks as the flexible coupling, while 2W6514 and 2W6943 Coupling Groups use rubber discs for the flexible coupling. The alignment procedure is the same for both type couplings. Use Special Instruction Form SEHS7456-01, ALIGNMENT OF CATERPILLAR MARINE TRANSMISSIONS AND MARINE ENGINES and Form SEHS7654, ALIGNMENT - GENERAL INSTRUCTIONS, along with this instruction for the correct alignment and installation procedures.

Put the marine transmission in alignment with the ship's propeller shaft as shown in Special Instruction Forms SEHS7456-01 and SEHS7654. Fasten the marine transmission to the ship's rails.

Since not all dial indicators indicate plus (+) in the same direction, it is necessary that a standard be established for the purpose of clarity in this instruction. In this instruction a plus (+) reading means that the tip of the indicator moved into the dial indicator; a minus (-) reading means that the tip of the indicator moved out of the dial indicator. Before taking any indicator readings, check the dial indicators being used to determine which is the plus (+) direction. If the plus (+) direction is different than the standard used in this instruction, keep this in mind when taking dial indicator readings.

8N8872 Coupling Group

(1) Remove cover (1) and rubber blocks (2) from coupling assembly (3). Install coupling assembly (3) on the flywheel. Use an 8S2328 Dial Indicator Group to measure the TIR (total indicator runout) at four places 90° apart around machined surfaces (Z) and (Y) on coupling (3). Use a pry bar to move the crankshaft to the front of its travel before each reading is taken. Make a record of these readings. If the TIR is not over 0.13 mm (.005") the engine can be put in approximate alignment to the marine gear without connecting the shaft to the coupling at this time. If the TIR is more than this, use the steps that follow to get the engine in approximate alignment with the transmission.

NOTE: The final alignment reading must be made while the engine and marine transmission are rotated together without rubber blocks (2) installed. Use the indicator on surface (Y) to measure the total end play on the crankshaft. This reading will be needed later in the instruction.

(2) Remove all dirt, rust and foreign material from the surfaces on transmission input flange (4), shaft assembly (5) and spacer group (6). Use a file to remove all burrs or damaged areas on the surfaces. Install spacer group (6) and shaft assembly (5) on flange (4) with bolts (7) and the nuts.

NOTE: arrows (8) on spacer (6) must be turned in the same direction, as shown. Loosely install bolts (7). Install bolt (9) through spacer (6) at (X) and tighten it. Tighten bolts (7).

(3) Measure the length of inside part (10) and outside part (11) of coupling (3). Fasten part (10) to shaft (5) with two bolts. Put the crankshaft in the center of its end play. Put a straightedge across points (W) and measure from the straightedge to point (V). This dimension must be one-half the difference in the lengths of parts (10) and (11). This will put part (10) so dimension (U) is the same on each side. If needed, move the engine to the front or rear to get the same dimension at (U).

(4) Install 6V2042 Alignment Yoke (12) and 6V2043 Alignment Bar (13) on shaft (5) with two 13.0 mmØ (.5") threaded rods and nuts. Install two dial indicators (14) and (15) as shown, one on surface (Y) and one on surface (Z). Use a pry bar to push the crankshaft to the front of its travel. Set the indicators to "0" in this position. Indicator (14) will show face alignment. Slowly turn shaft (5) by hand; do not use yoke (12) to turn the shaft. Make a record of the indicator readings 90° apart at (A), (B), (C) and (D).

Face alignment as shown by the indicator must be as follows:

a) A maximum TIR between (A) and (C) of 0.25 mm (.010") is permitted. The reading at (C) must be plus (+). This dimension is needed because, with application of engine torque to the propeller shaft, the transmission will tip forward a small amount and both dimensions will be the same.

b) A maximum TIR between (B) and (D) of 0.25 mm (.010") is permitted, but the reading at (B) plus the reading at (D) must be equal to the reading at (C).

(5) Indicator (15) on surface (Z) will show bore alignment. Put the indicator on "0" at location (A). Slowly turn shaft (5) and make a record of the indicator readings, 90° apart at (A), (B), (C) and (D).

(6) Bore alignment as shown by indicator (15) must be as follows:

a) The TIR between (A) and (C) must be 0.64 ± 0.25 mm (.025" ± .010"). IMPORTANT: Because the centerline of the crankshaft must be below the centerline of the coupling shaft, the indicator reading at (C) must be plus (+) when the reading at (A) is 0.00 mm (.000") and indicator (15) is installed as shown.

b) The TIR between (B) and (D) can be a maximum of 0.13 mm (.005"). The readings at (B) plus (D) must equal the reading at (C).

(7) Move the engine as necessary to get the correct alignment dimensions.

(8) Connect shaft (5) to coupling (3) with bolts (16). Put two pieces of 50.0Ø mm (2.0") pipe (17), approximately 100.00 mm (4.0") long, in coupling (3) approximately 180° apart as shown. Again install the dial indicator on surfaces (Y) and (Z). Put the indicators to zero at the top. Turn the crankshaft in the direction of normal rotation and check the indicator readings at 90° intervals, (A), (B), (C) and (D). The readings taken with the shaft connected to the coupling will give an accurate reading because any variations caused by runout on the shaft or the coupling will be eliminated. Put a straightedge across points (W). Measure from the straightedge to point (V). This dimension should be the same as in step (3), page (3). If needed, move the engine to get the original dimension. Again check the bore and face alignment at (Y) and (Z).

(9) If the readings are within the tolerances given earlier, do not move the engine. If the readings are not within the correct tolerances, make adjustments to the alignment as necessary. Remove the pipes and install ten rubber blocks (2). Install cover (1).

(10) Again install a dial indicator on the flywheel housing and check the total end play on the crankshaft. You must get the same dimension as found in step 1, page 2.

(11) Remove the bolt from spacer (6) at location (X). Keep the bolt for future service work.

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Do not run the engine with the bolt installed through spacer (6). The bolt could break and centrifugal force can throw the bolt out and cause personal injury.

2W6514 And 2W6943 Coupling Groups

(1) These coupling groups are installed by the same procedure. 2W6943 Coupling Group has a torsional stop in it, while 2W6514 does not have the torsional stop.

(2) Install coupling assembly (1) on the flywheel. Use an 8S2328 Dial Indicator Group to measure the TIR (total indicator runout) at four places, 90° apart, around machined surfaces (Z) and (Y) on coupling (1). Use a pry bar to move the crankshaft to the front of its travel before each reading is taken. Make a record of these readings. If the TIR is not more than 0.13 mm (.005"), the alignment procedure can be done without the shaft connected to the coupling at this time. If the TIR is more than this, use the steps that follow to get the engine in approximate alignment with the transmission.

NOTE: The final alignment readings must be made while the engine and marine transmission are rotated together without spacer (2) installed. Use the indicator on surface (Y) to measure the total end play on the crankshaft. This reading will be needed later in the instruction.

(3) Remove all dirt, rust and foreign material from the surfaces on transmission input flange (3), shaft assembly (4) and spacer group (2). Use a file to remove all burrs or damaged areas on the surfaces. Install shaft assembly (4) on flange (3) with bolts (5) and the nuts. Push the crankshaft to the front of its travel with a pry bar. Loosely install spacer (2). Put a feeler gauge equal to one-half the crankshaft end play (see step 2, page 6 for the dimension) between spacer (2) and coupling (1) at (S). Move the engine to the front or rear as needed to get clearance equal to the feeler gauge thickness. Remove spacer (2). Install 6V2042 Alignment Yoke (6) and 6V2043 Alignment Bar (7) on shaft (4) with two 13.0 mm Ø (.5"Ø) threaded rods and nuts. Install two dial indicators (8) and (9) as shown, one on surface (Y) and one on surface (Z). Use a pry bar to push the crankshaft to the front of its travel. Set the indicators to "0" in this position.

(4) Indicator (8), on surface (Y), will show face alignment. Slowly turn shaft (4) by hand; do not use yoke (6) to turn the shaft. Make a record of the indicator readings 90° apart at (A), (B), (C) and (D). Face alignment as shown by the indicator must be as follows:

a) A maximum TIR between (A) and (C) of 0.25 mm (.010") is permitted. The reading at (C) must be plus (+). This dimension is needed, because as an application of engine torque is made to the propeller shaft, the transmission will tip forward a small amount and both dimensions will be the same.

b) A maximum TIR between (B) and (D) of 0.25 mm (0.010") is permitted but the reading at (B) plus the reading at (D) must be equal to the reading at (C).

(5) Indicator (9) on surface (Z) will show bore alignment. Put the indicator on "0" at location (A). Slowly turn shaft (4) and make a record of the indicator readings 90° apart at (A), (B), (C) and (D). Bore alignment as shown by indicator (9) must be as follows:

a) The TIR between (A) and (C) must be 0.64 ± 0.25 mm (.025" ± .010"). IMPORTANT: Because the centerline of the crankshaft must be below the centerline of the coupling shaft, the indicator reading at (C) must be plus (+) when the reading at (A) is 0.00 mm (.000") and indicator (9) is installed as shown.

b) The TIR between (B) and (D) can be a maximum of 0.13 (.005"). The reading at (B) plus (D) must equal the reading at (C).

(6) Move the engine as necessary to get the alignment dimensions given.

(7) Loosely connect shaft (4) to coupling (1) with two bolts (18). Do not install the spacer between the shaft and the coupling at this time. Rotate the engine and transmission input shaft together and take the dial indicator readings on surfaces (Y) and (Z) 90° apart at (A), (B), (C) and (D). If the alignment readings are not within the specifications given earlier, make the adjustments as shown in steps 4, 5 and 6 on pages 7 and 8. The engine and transmission must be rotated together to get the final reading.

(9) Push the crankshaft to the front of its travel with a pry bar. Loosely install spacer (2). Put a feeler gauge equal to one half the crankshaft end play (see step 2, page 6, for the dimension) between spacer (2) and coupling (1) at (S). Move the engine to the front or rear as needed to get clearance equal to the feeler gauge thickness. Remove spacer (2) and again check the alignment of the engine to the transmission. Make adjustments as necessary. Install spacer (2) with bolts (18) but do not tighten. The arrows on each half of spacer (2) must point in the same direction. Install bolt (19) and the nut through both halves of spacer (2); tighten the bolt. Tighten bolts (18) to 270 ± 25 N·m (200 ± 20 lb-ft) torque. Remove bolt (19) and keep it for future service work. Do not run the engine with bolt (19) installed. Again check the end play on the drankshaft to be sure it is the same dimension found in step 2, page 6.

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Do not run the engine with bolt (19) installed. The bolt could break and centrifugal force can throw the bolt out and cause personal injury.

All Couplings

(1)

a) Drill the mounting holes through the engine bed using the holes in the engine mounting rails as a guide. Use dowels or fitted bolts at locations (E) of the mounting rails. Clearance type bolts must be used at all other locations. The holes for the dowels or fitted bolts must be an interference fit. Holes for clearance type bolts must be 1.5 mm (.06") less than the diameter of the holes in the engine mounting rails.

b) Either steel shims or poured resin shims can be used between the engine rails and engine bed at (R). See Special Instruction Form SEHS7456-01 for the correct installation procedures.

c) If steel shims are to be used, see MOUNTING MARINE TRANSMISSIONS AND ENGINES WITH STEEL SHIMS on page 6.

d) If poured resin shims are to be used, see MOUNTING MARINE TRANSMISSIONS AND ENGINES WITH POURED RESIN SHIMS on page 8.

e) After the shims have been installed and the mounting nuts tightened, again check the face and bore alignment to be sure that it is correct.

f) If there are alignment marks on the outside diameter of the companion flange and output flange, rotate the output flange until these marks are in alignment. Move the tailshaft forward until the flange faces are in full contact. Install the flange bolts and tighten them to their specified torque.

g) After alignment has been completed and all anchor bolts have been tightened to their final torque, the engine crankshaft deflection check, shown on page 31, must be performed.

(2) When all measurements and adjustments are complete, install all guards and shields over the coupling.

Checking Engine Crankshaft Deflection

NOTE: The following procedure must be used on all 3512 and 3516 Engines after alignment of the marine transmission and engine, and after installation of the shims and anchor bolts. Do this procedure with both a cold engine and a hot engine.

(1) Remove the inspection cover from the side of the cylinder block to expose the crankshaft center main bearing journal. Rotate the crankshaft until the counterweights on the center throw are just past the connecting rods. Install a Starrett Crankshaft Distortion Dial Gauge No. 696 with a No. 696B Balancer Attachment on either side of the center main bearing journal with the indicator pivot points positioned approximately 6.4 mm (.25") from faces (A) and/or (B) as shown.

Zero the dial indicator. Make sure the indicator pivot points are seated properly by rotating the gauge about its own axis until it will hold a zero reading. Continue to rotate the crankshaft from the starting position until the gauge approaches interference with the connecting rod on the opposite side. Continuously observe the gauge reading while rotating the crankshaft through approximately 300° of rotation.

Rotate the crankshaft back to the original starting position. The indicator reading must return to zero at the original starting position in order to make a valid test. If the indicator did not return to a zero reading, the indicator shaft points were not seated and the test procedure must be repeated.

Crankshaft deflection, as measured by a change in dimension (X), must not exceed 0.01 mm (-.0005") [close in] or +0.025 (+.001") [spread out]. If the change in dimension (X) exceeded these values, cylinder block distortion has occurred due to improper shimming under the mounting rails. Loosen the bolts that fasten the engine rails to the ship's engine bed. Install the correct thickness of shims as necessary between the rails and engine bed to ensure that each mounting point is carrying its portion of the load. Check face and bore alignment again to be sure that they are correct. Repeat the crankshaft deflection check if the thickness of any of the shims was changed.