Part 2
PISTONS AND CONNECTING RODS
Removal
Follow removal steps outlined in illustration.
Removal Service Points
[A] Connecting Rod Cap Removal.
1. Mark the cylinder number on the side of the connecting rod big end for correct reassembly.
2. Keep the removed connecting rods, caps, and bearings in order according to the cylinder number.
[B] Piston Pin Removal.
1. Remove the stop screw from the blase.
2. Select the correct piston support for your application. Fit the piston support onto the base. Place the base on press support blocks.
3. Insert the press pin through the piston pin hole. Select the correct connecting rod guide pin. Thread the guide pin onto the threaded portion of the press pin.
4. Position the piston assembly on the piston support in the press. With the press pin up, insert the guide pin through the hole in the piston and through the hole in the piston support.
5. Press the piston pin out of the assembly.
IMPORTANT: To avoid piston damage,
- The piston support must seat squarely against the piston.
- Verify that the piston pin will slide through the hole in the piston support.
6. Remove the piston pin from the press pin.
Installation
Installation in reverse order as removal.
Installation Service Points
]A[ Piston Pin Installation.
1. Thread the stop screw and lock nut assembly into the base. Fit the correct piston support on top of the base. Insert the press pin, threaded end up, into the hole in the piston support until the press pin touches the stop screw.
2. Using the markings on the press pin, adjust the stop screw to the depth as shown below.
3. Place the base on press support blocks.
4. Slide the piston pin over the threaded end of the press pin, and thread the correct guide pin up against it.
5. Coat the piston pin with oil, and with the connecting rod held in position, slide the guide pin through the piston and connecting rod.
6. Press the piston pin through the connecting rod until the guide pin contacts the stop screw.
7. Remove the piston assembly from the base. Remove the guide pin and press pin from the assembly.
IMPORTANT: Due to production tolerance variations, it is necessary to visually inspect the piston pin depth after installation to verify that the piston pin is centered. Adjust if necessary.
8. Check that the piston moves smoothly.
]B[ Oil Ring Installation.
1. Fit the oil ring spacer into the piston ring groove. Then fit the upper and lower side rails.
NOTE:
1. The spacer and side rails may be fitted in either direction. No distinction is made between top and bottom.
2. Spacer and side rail sizes are color-coded as follows:
To install a side rail, fit one end of the rail into the groove, then press the rest of the rail into position by hand as shown.
CAUTION: Do not fit side rails using a piston ring expander since they may break.
2. After installing the side rails, check that they more smoothly in both directions.
]C[ Piston Ring No.2 /Piston Ring No.1 Installation.
1. Using a ring expander, fit ring No.2 and ring No.1 with their identification marks facing upward (on the piston crown side).
Identification mark:
No.1 ring: T
No.2 ring: T2
NOTE: The piston ring is stamped with the following size mark.
]D[ Piston and Connecting Rod Assembly Installation.
1. Apply oil to the piston, piston ring, and oil ring.
2. Align the gaps of the piston rings and oil rings (side rails and spacer).
3. With the piston crown's front arrow mark pointing toward the timing belt side, press the piston and connecting rod assembly into the cylinder from the top of the cylinder.
4. Compress the piston rings tightly with a suitable ring compression tool, then press the piston and connecting rod fully into the cylinder. Do not strike the piston hard since the piston rings may break and the crank pin may be nicked.
]E[ Connecting Rod Bearing Installation.
1. When replacing the bearings and/or crankshaft, read off the identification mark on the crankshaft, and select a bearing according to the following table.
]F[ Connecting Rod Cap Installation.
1. Aligning the marks made during disassembly, fit the bearing cap onto the connecting rod. If the connecting rod is new and has no index mark, ensure that the bearing locking notches are both on the same side.
2. Check that the connecting rod big end side clearance confirms with specification.
Standard value: 0.10 - 0.25 mm (0.0039 - 0.0098 inch)
Limit: 0.4 mm (0.016 inch)
]G[ Connecting Rod Cap Nut Tightening.
1. Since the connecting rod cap bolts and nuts are torqued using the plastic area tightening method, the bolts should be examined BEFORE reuse. If the bolt threads are "necked down", the bolt should be replaced.
Necking can be checked by running a nut with your fingers the full length of the bolt threads. If the nut does not run down smoothly, the bolt should be replaced.
2. Before installation of each nut, apply engine oil to the nut.
3. Install each nut to the bolt and finger-tighten it. Then tighten the nuts alternately to install the cap properly.
4. Tighten the nuts to a torque of 20 Nm (15 ft. lbs.).
5. Make a paint mark on the head of each nut.
6. Make a paint mark on the bolt end at the position 90° to 100° from the paint mark made on the nut in the direction of tightening the nut.
7. Give a 90° to 100° turn to the nut and make sure that the paint mark on the nut and that on the bolt are in alignment.
CAUTION:
1. If the nut is turned less than 90°, proper fastening performance may not be expected. When tightening the nut, therefore, be careful to give a sufficient turn to it.
2. If the nut is overtightened (exceeding 100°), loosen the nut completely and then retighten it by repeating the tightening procedure from step (1).
Inspection
Piston Ring
1. Check for side clearance.
If the limit is exceeded, replace the ring or piston, or both.
Standard value:
No.1: 0.03 - 0.07 mm (0.0012 - 0.0028 inch)
No.2: 0.02 - 0.06 mm (0.0008 - 0.0024 inch)
Limit:
No.1: 0.1 mm (0.0039 inch)
No.2: 0.1 mm (0.0039 inch)
2. Install the piston ring into the cylinder bore. Force the ring down with a piston, the piston crown being in contact with the ring, to correctly position it at right angles to the cylinder wall. Then, measure the end gap with a feeler gauge.
If the end gap is excessive, replace the piston ring.
Standard value:
No.1: 0.25 - 0.40 mm (0.0098 - 0.0157 inch)
No.2: 0.40 - 0.55 mm (0.0157 - 0.0217 inch)
Oil: 0.20 - 0.60 mm (0.0078 - 0.0236 inch)
Limit:
No.1, No.2: 0.8 mm (0.031 inch)
Oil: 1.0 mm (0.039 inch)
Crankshaft Pin Oil Clearance (Plastic Gauging Material Method)
1. Remove oil from the crankshaft pin and connecting rod bearing.
2. Cut the plastic gauging material to the same length as the width of bearing and place it on crankshaft pin in parallel with its axis.
3. Install the connecting rod cap carefully and tighten the nuts to the specified torque.
4. Carefully remove the connecting rod cap.
5. Measure the width of the plastic gauging material at its widest part by using a scale printed on its package.
Standard value: 0.02 - 0.05 mm (0.0008 - 0.0020 inch)
Limit: 0.1 mm (0.004 inch)
CRANKSHAFT AND CYLINDER BLOCK
Removal
CAUTION: Do not remove any of the bolts "A" of the flywheel shown in the illustration. The balance of the flexible type flywheel is adjusted in an assembled condition. Removing the bolt, therefore, can cause the flexible flywheel to be out of balance, giving damage to the flywheel.
Follow removal steps outlined in illustration.
Installation
Installation in reverse order as removal.
Installation Service Points
]A[ Crankshaft Bearing Installation.
1. When replacing the bearings, crankshaft and/or cylinder block, read off the identification mark on the crankshaft and cylinder block (as illustrated), and select a bearing according to the following table.
2. Install bearings having an oil groove to the cylinder block.
3. Install bearings having no oil groove onto the bearing caps.
4. Install the thrust bearings at the No.3, upper bearing with the grooved side toward the crankshaft web.
]B[ Bearing Cap /Bearing Cap Bolt Installation.
1. Install the bearing cap so their arrow is positioned on the timing belt side.
2. When reusing the bearing cap bolt, measure that its shank length dose not exceed the specified limit. Replace the bolt if this measurement exceeds the limit.
Limit: maximum 71.1 mm (2.799 inch)
3. Apply engine oil to the bolt thread and flange of the bolt.
4. Tighten the bearing cap bolts to 25 Nm (18 ft. lbs.) torque in the sequence shown.
5. Make a paint mark on the head of each bolt.
6. Make a paint mark on the bearing cap at the position 90° to 100° from the paint mark on the bolt head in the direction of tightening the bolt.
7. Give a 90° to 100° turn to the bolt in the tightening sequence. Make sure that the paint mark on the bolt and that on the bearing cap are in alignment.
CAUTION:
1. If the bolt is turned less than 90°, proper fastening performance may not be expected. When tightening the bolt, therefore, be careful to give a sufficient turn to it.
2. If the bolt is overtightened (exceeding 100°), loosen the bolt completely and then retighten it by repeating the tightening procedure from step (1).
8. Check that the crankshaft rotates smoothly.
9. Measure the end play in the crankshaft. If the measurement exceeds the specified limit, replace the crankshaft bearings.
Standard value: 0.05 - 0.25 mm (0.0020 - 0.0098 inch)
Limit: 0.4 mm (0.016 inch)
]C[ Rear Oil Seal Installation.
]D[ Sealant Application To Oil Seal Case.
Specified sealant:
Mitsubishi Genuine Part No. MD970389 or equivalent.
]E[ Drive Plate Bolt/flywheel Bolt Installation.
1. Remove all the remaining sealant from bolts and thread holes of crankshaft.
2. Apply engine oil to the flange of bolt.
3. Apply engine oil into the thread holes of crankshaft.
4. Apply specified sealant to the thread of bolt.
Specified sealant:
3M Nut Locking Part No. 4171 or equivalent.
5. Tighten the bolts to specified torque.
Inspection
Crankshaft Journal Oil Clearance (Plastigage Method)
1. Remove oil from the crankshaft journal and the crankshaft bearing.
2. Install the crankshaft.
3. Cut the Plastigage to the same length as the width of bearing and place it on the journal in parallel with its axis.
4. Install the crankshaft bearing cap carefully and tighten the bolts to the specified torque.
5. Carefully remove the crankshaft bearing cap.
6. Measure the width of the Plastigage at its widest part by using a scale printed on the Plastigage package.
Standard value: 0.02 - 0.04 mm (0.0008 - 0.0016 inch)
Limit: 0.1 mm (0.004 inch)
Cylinder Block
1. Visually check for cracks, rust, and corrosion, and inspect the cylinder block using a flaw detecting agent. Rectify defects where possible or replace the cylinder block.
2. Ensure that the top surface is free of gasket chips and other foreign material. Check the cylinder block top surface for distortion using a straight edge and feeler gauge.
Standard value: 0.05 mm (0.0020 inch) or less
Limit: 0.1 mm (0.004 inch)
3. If the distortion is excessive, correct within the allowable limit or replace.
Grinding limit: 0.2 mm (0.008 inch)
The total thickness of the stock allowed to be removed from cylinder block and mating cylinder head 0.2 mm (0.008 inch) at maximum.
Cylinder block height (when new):
263.5 mm (10.374 inch)
4. Check the cylinder walls for cracks and seizure marks. If defects are evident, bore all the cylinders to oversize or replace the cylinder block.
5. Using a cylinder gauge, measure each cylinder bore and cylindricity. If any cylinder is severely worn, bore all the cylinders to oversize and replace the piston and piston rings accordingly. Take measurements at the points shown.
Standard value:
Cylinder bore l.D.: 81.0 mm (3.19 inch)
Cylindricity: 0.01 mm (0.0004 inch) or less
Boring Cylinder
1. Oversize pistons should be based on the largest bore cylinder.
NOTE: The size mark is stamped on the piston top.
2. Measure the outside diameter of piston to be used. Measure it in thrust direction as shown.
3. Based on the measured piston O.D., calculate the boring finish dimension.
Boring finish dimension = Piston O.D. + (Clearance between piston O.D. and cylinder) - 0.02 mm (0.0008 inch) (honing margin)
4. Bore each cylinders to the calculated boring finish dimension.
CAUTION: To prevent distortion caused by heat increased during boring, bore the cylinders in the following order: No.2, No.4, No.1, No.3.
5. Hone the cylinders to the final finish dimension (Piston O.D. + Piston-to-cylinder clearance,.
6. Check the clearance between piston and cylinder.
Standard value: 0.02 - 0.04 mm (0.0008 - 0.0016 inch)
NOTE: When boring cylinders, finish all of four cylinders to the same oversize. Do not bore only one cylinder to an oversize.