Piston and Connecting Rod
PISTON AND CONNECTING RODDISASSEMBLY AND REASSEMBLY
Disassembly Steps 1-12:
SERVICE POINTS OF DISASSEMBLY
2. REMOVAL OF CONNECTING ROD CAP
Mark the large end of the. connecting rod with the cylinder number for use during reassembly.
7. REMOVAL OF NO.1 PISTON RING/8. NO.2 PISTON RING
Remove the piston rings with a piston expander.
10. REMOVAL OF PISTON PIN
1. Fit the piston and the connecting rod assembly to the body of the special tool. Set the front mark (Triangle) on the upper surface of the piston and the front mark (G6) in the center of the connecting rod so that they face upwards.
2. Place piston and connecting rod with arrow mark or identification mark upward over anvil so lip of insert in between connecting rod boss and inside surface of piston. The connecting rod boss should bear on as much of the insert surface as possible.
3. Adjust connecting rod rear support until rod is horizontal to press bed surface. Misalignment of pin and receiving tube may result if support adjustment is not correct.
4. Position piston pin pusher onto pin and remove pin with press ram.
CAUTION: As piston pin is removed, It must pass through receiving tub. Check alignment and adjust if necessary.
INSPECTION
PISTON AND PISTON PIN
Refer to P.11-57.
PISTON RING
1. Check the piston ring for damage, excessive wear, and breakage and replace if defects are evident. If the piston has been replaced with a new one, the piston rings must also be replaced with new ones.
2. Check the clearance between the piston ring and ring groove. 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 in.)
No.2 : 0.02-0.06 mm (0.0008-0.0024 in.)
Limit:
No.1 : 0.1 mm (0.004 in.)
No.2 : 0.1 mm (0.004 in.)
3. Install the piston ring into the cylinder bore. Force it down with a piston, its 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 ring gap is excessive, replace the piston ring.
Standard value:
No.1 : 0.25-0.40 mm (0.0098-0.0157 in.)
No.2 : 0.20-0.35 mm (0.0079-0.0138 in.)
Oil : 0.20-0.70 mm (0.0079- 0.0276 in.)
Limit:
No.1, No.2 : 0.8 mm (0.031 in.)
Oil : 1.0 mm (0.039 in.)
CONNECTING ROD BEARING
1. Visually check the bearing surface for uneven contact, streaks, scratches, and seizure. Replace if defects are evident. If streaks and seizure are excessive, check also the crankshaft. If damage is present on the crankshaft, replace crankshaft or regrind to undersize for reuse.
2. Measure the connecting rod bearing I.D. and crankshaft pin O.D. if the oil clearance exceeds the limit, replace bearing, and crankshaft if necessary. Or, regrind the crankshaft to an undersize and replace bearing with an undersize one.
Standard value: 0.02-0.05 mm (0.0008-0.0020 in.)
Limit: 0.1 mm (0.004 in.)
NOTE: For oil clearance measuring method using the plastic gauge, refer to the section CRANKSHAFT.
SERVICE POINTS OF REASSEMBLY
10. INSTALLATION OF PISTON PIN
1. Thread stop plug approximately half way into the bottom of the receiving tube.
2. Select the largest diameter piston pin guide that will pass through piston and rod. install spring, spacer, and guide into receiving tube.
3. With connecting rod removed from piston, insert piston pin into piston bore. Carefully measure amount of pin that protrudes equally from both sides of piston. Record this measurement for further use.
4. Position connecting rod and piston over the anvil. The spring loaded piston guide will pass through piston and rod and align it. Lubricate pin and insert it into piston.
5. Place piston pin pusher on piston pin and push pin through connecting rod until the pin protrudes some distance measured and recorded above in step 3.
CAUTION: The piston must be free to float during installation; check frequently.
6. Apply hydraulic pressure to pin and adjust stop plug until stop plug comes in contact with spacer.
7. Remove piston and pin assembly from anvil and check piston pin to make sure it is centered. If it is not centered. adjust stop plug up or down to obtain proper centering. The pin stop is now set for any remaining pistons.
CAUTION: If the required installation load is out of specification replace piston pin and/or connection rod.
Piston pin press in load : 7,500-17,500 N (1,653-3,858 lbs.)
9. INSTALLATION OF OIL RING
1. Fit the oil ring spacer into the piston ring groove.
NOTE: The side rails and spacer may be installed in either direction.
2. Install the upper side rail.
To install the side rail, first fit one end of the rail into the piston groove, then press the remaining portion into position by finger. See illustration.
Use of ring expander to expand the side rail end gap can break the side rail, unlike other piston rings.
NOTE: Do not use piston ring expander when installing side rail.
3. Install the lower side rail in the same procedure as described in step (2).
4. Make sure that the side rails move smoothly in either direction.
8. INSTALLATION OF PISTON RING NO.2/7. PISTON RING NO.1
Using a piston ring expander, fit the No.2 and then No.1 piston ring into position.
NOTE:
1. Note the difference in shape between No.1 and No.2 piston rings.
2. Install piston rings No.1 and No.2 with their side having marks facing up (on the piston crown side).
4. INSTALLATION OF PISTON AND CONNECTING ROD
1. Apply an ample amount of engine oil to the piston outside surfaces, piston rings, and oil ring.
2. Position the piston ring and oil ring (side rail and spacer) end gaps as shown in the illustration.
3. Insert the piston and connecting rod assembly into the cylinder, working from the cylinder top surface. Make sure that the front mark stamped on the piston top surface and that (identification mark) on the connecting rod face the front of engine.
Identification mark:
Piston: (Non-Turbo) 63D
(Turbo) 63DT
Connecting rod: G6
4. With the piston rings held in position with a piston ring compressor, insert the piston and connecting rod assembly. Driving the assembly into position by using excessive force can result in a damaged piston ring or crankshaft pin.
2. INSTALLATION OF CONNECTING ROD CAP
1. Mate the correct bearing cap with the correct connecting rod by checking with the alignment marks marked during disassembly. If a new connecting rod is used which has no alignment mark. position the notches for locking the bearing on the same side.
2. Check if the thrust clearance in the connecting rod big end is correct.
Standard value: 0.10-0.25 mm (0.0040-0.0098 in.)
Limit: 0.4 mm (0.0157 in.)