016- Piston, Piston rings, Connecting Rod.docx

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MBE 4000 '04 workshop manual

Text of 016- Piston, Piston rings, Connecting Rod.docx

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Section 1.18 Piston, Piston Ring, and Connecting RodThe pistons are made of aluminum alloy with ring carriers and a shallow combustion chamber recess. The pistons are cooled by oil spray nozzles. See Figure "Piston Assembly (exploded view)" for an exploded view of the piston and connecting rod assembly.

1. Piston and Rings 2. Wrist Pin 3. Snap Ring

4. Connecting Rod 5. Bearing Cap 6. Connecting Rod Stretch Bolt

7. Bearing Shell

Figure 1. Piston Assembly (exploded view) The difference from the non-EGR engine cylinder liner to the EGR engine is a groove on the top part of the cylinder liner, which houses the carbon scraper ring. The EGR engine uses a new tool for piston installation; however, all other procedures are the same for the EGR and nonEGR engine. Section 1.18.1 Piston Removal Remove the piston assembly as follows: 1. Remove each cylinder head, as required. Refer to "1.2.1 Cylinder Head Removal" . Note: The MBE 4000 engine has individual heads for each cylinder. To remove one piston, do these procedures step by step. To remove all the pistons, repeat each step in these instructions, as applicable, for all six pistons. 2. Remove the oil pan.

NOTICE:Do not damage the piston travel surface of the cylinder. 3. Using a plastic scraping tool, carefully scrape off any combustion residues from the combustion area in the cylinder in order to avoid damage to the piston rings when the piston is removed. 4. Install the engine barring tool (J46392) . Refer to "1.16.1 Engine Barring Tool Installation" . 5. Be sure the connecting rods and the bearing caps are marked so that they can be matched for installation. See Figure "Checking Rod and Bearing Cap Markings" .

1. Bearing Cap

2. Connecting Rod

Figure 2. Checking Rod and Bearing Cap Markings 6. Remove and inspect the oil spray nozzles. Replace them if damaged. See Figure "Location of Oil Spray Nozzle" .

1. Oil Spray Nozzle Figure 3. Location of Oil Spray Nozzle

2. Cylinder Liner

7. Remove the connecting rod stretch bolts and bearing cap. See Figure "Removing the Bearing Caps" .

Figure 4. Removing the Bearing Caps Note: If the bearing shell halves are removed from the rods and caps, be sure to mark them so they can be matched for installation. 8. Remove the bearing shell halves from the bearing cap and connecting rod.

NOTICE:The carbon scraper ring has a smaller internal diameter than the piston skirt diameter; therefore, the piston installation and removal must be carried out with the carbon scraper ring removed. 9. Note: Step 9 only applies to EGR engines. For non-EGR engines, go to step 10 . 10. Note: Piston removal in the EGR engine is performed with the engine facing upright not turned on it's side. 11. Remove the carbon scraper ring from the cylinder liner groove. See Figure "Removing Carbon Scraper Ring" .

1. Cylinder Liner 2. Carbon Scraper Ring

3. Installed Piston 4. Installed Carbon Scraper Ring

Figure 5. Removing Carbon Scraper Ring 12. Push the piston and connecting rod out of the cylinder, and remove them both from the cylinder block. 13. Secure the connecting rod in a vise with protective jaws.

NOTICE:Be sure the vise jaws are adequately lined to prevent the rod surface from being nicked or marred in any way. Such surface damage could lead to later rod cracking or breaking. 14. Remove the piston rings from the piston. Refer to "1.18.3 Piston Ring Replacement" . 15. Remove the wrist-pin snap rings. Push the wrist pin out and remove the piston from the connecting rod.

Section 1.18.1.1 Piston Inspection

Inspect the piston as follows: 1. Remove the piston. Refer to "1.18.1 Piston Removal" . 2. Check the diameter of the wrist pin and the wrist pin bore. See Figure "Piston Assembly (exploded view)" . Specifications are listed in Table "Piston Inspection Specifications" .

1. Piston and Rings 2. Wrist Pin 3. Snap Ring

4. Connecting Rod 5. Bearing Cap 6. Connecting Rod Stretch Bolt

7. Bearing Shell

Figure 6. Piston Assembly (exploded view) Description Piston Compression Height Wrist Pin Bore Diameter Wrist Pin Diameter Dimensions: mm (in.) 79.50-79.55 (3.130-3.132) 52.03-52.04 (2.0484-2.0488) 51.992-51.998 (2.0469-2.0472)

Table 9. Piston Inspection Specifications 3. Inspect the cylinder liner and piston for damage and signs of wear. Replace any piston with damage to the snap ring grooves, cracks in the piston wall, or signs of seizing and/or erosion. 4. Check the tolerance code on the piston and compare it to the tolerance code on the cylinder liner. See Figure "Tolerance Codes" .

1. Piston Figure 7. Tolerance Codes

2. Cylinder Liner

5. Check the condition of the piston rings. Replace any worn, damaged, or chipped rings. Refer to "1.18.3 Piston Ring Replacement" . 6. Check the connecting rod for any unusual condition. Refer to "1.18.1.2 Connecting Rod End Play Measurement" . 7. Measure the diameters of the bearing shell bore and crankshaft journals. Refer to "1.18.1.3 Connecting Rod Radial Play Measurement" for instructions. 8. Check the length of the connecting rod stretch bolts. See Figure "Measuring a Stretch Bolt" . Replace any bolts that exceed the maximum length of 68.5 mm (2.70 in.).

1. Shank

Figure 8. Measuring a Stretch BoltSection 1.18.1.2 Connecting Rod End Play Measurement

Measure the connecting rod end play as follows: 1. Remove the piston. Refer to "1.18.1 Piston Removal" . 2. Inspect the connecting rod for blue discoloration (indicates bearing damage), scoring, notches, and cracks. If any of these conditions are found, replace the connecting rod. 3. Measure the inside diameter of the bushing in the small bore of the connecting rod. Use a quick-release caliper (internal measurement, 40 to 60 mm), with a dial gauge and holder. See Figure "Measuring Inside Diameters in the Connecting Rod" . If the value exceeds 52.07 mm (2.050 in.), replace the connecting rod.

1. Dial Gauge 2. Dial Gauge Holder 3. Bushing

4. Connecting Rod 5. Bearing Shell (2 halves) 6. Bearing Cap

7. Stretch Bolt (2 qty.)

Figure 9. Measuring Inside Diameters in the Connecting Rod Note: Checking the connecting rod for a twisted or bent condition in the next step requires machine shop equipment such as a caliper gauge with a round scale.

NOTICE:Do not attempt to straighten the connecting rod. This could result in severe engine damage. 4. Inspect the connecting rod for twisting and dimensional tolerance. see Figure "Connecting Rod Measurements" . If any value exceeds those listed in Table "Connecting Rod Dimensional Tolerances" , replace the connecting rod.

Figure 10. Connecting Rod Measurements Description Length of Connecting Rod Basic Bore Diameter for Connecting Rod Bearings Maximum Permissible Out-of-Round in Bearing Bore Maximum Permissible Out-of-Round in Bushing Bore Maximum Difference in Axial Parallelism Between Bearing Bore and Bushing Inner Surface Width of Connecting Rod (at big end) Width of Connecting Rod Journal Dimensions: mm (in.) 255.970-256.030 (10.0775-10.0799) 99.000-99.022 (3.89763.8985) 0.01 (0.0004) 0.01 (0.0004) 0.030 (0.0012) 44.308-44.370 (1.7441.7468) 44.5-44.6 (1.75-1.76)

Description Distance from Connecting Rod Center Line for Measuring Parallelism Table 14. Connecting Rod Dimensional Tolerances

Dimensions: mm (in.) 50 (2)

1. On each side of the connecting rod, measure the length of the connecting rod (Dimension A in figure "Connecting Rod Measurements" ): the distance from the center bearing bore (big-end bore) to the center of the bushing (small-end bore). The measurement must be within 255.970 to 256.030 mm (10.0775 to 10.0799 in.). 2. Measure the difference in axial parallelism (Dimension B in figure "Connecting Rod Measurements" ): between the bearing bore and the inner surface of the bushing, at 50 mm (2 in.) from the connecting-rod centerline (Dimension C in figure "Connecting Rod Measurements" ). The maximum allowed difference is 0.030 mm (0.0012 in.). 3. Measure the diameter of the connecting rod basic bore, with the bearing shells removed. The diameter of the basic bore must be between 99.000 to 99.022 mm (3.8976 to 3.8985 in.). 4. Measure the maximum permissible out-of-round in the bearing bore, with the bearing shells removed. The maximum permissible is 0.01 mm (0.0004 in.). 5. Calculate the connecting rod end play, or axial play, (fore-to-aft movement) on the crankshaft. If the end play is less than 0.130 mm (0.0051 in.), or more than 0.292 mm (0.0115 in.), replace the connecting rod, listed in Table "Connecting Rod Dimensional Tolerances" . 1. For each bearing journal, note the width (thickness) of the bearing journal. Example: Wj = 1.8120 inches. 2. For each connecting rod, note the width (thickness) of the rod. Example: Wr = 1.8050 inches. 3. From the value for the journal width, subtract the value for the connecting rod width. This result is the end play. Example: Wj Wr = 0.0070 inch. 6. Remove the bolts and bearing cap when ready to install the piston. 7. Install the piston. Refer to "1.18.2 Piston Installation" .Section 1.18.1.3 Connecting Rod Radial Play Measurement

Measure the connecting rod radial play as follows: 1. Remove the piston. Refer to "1.18.1 Piston Removal" . 2. Using a chamois cloth, clean the bearing bores in both the connecting rod and the bearing cap.

3. Install the two matched halves of the bearing shell, as marked on removal, into the connecting rod and into the bearing cap. Be sure the locking lugs on the bearing shells fit into the grooves in the rod and cap. See Figure "Bearing Shell Replacement" .

1. Connecting Rod 2. Bearing Shell (2 halves) Figure 11. Bearing Shell Replacement

3. Bearing Cap 4. Connecting Rod Bolt

4. Install the bearing c