Piston and Connecting Rods

REMOVAL AND INSTALLATION

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 base.








2. Select the correct piston support for your application. (See above) Fit the piston support onto the base. Place the base on the press support blocks.





3. Insert the press pin through the piston pin hole. Select the correct connecting rod guide pin. (See above.) 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 as shown in the illustration, insert the guide pin through the hole in the piston and through the hole in the piston support.

CAUTION: 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.

5. Press the piston pin out of the assembly.
6. Remove the piston pin from the piston pin.

Installation Service Points
]A[ Piston Pin Installation





1. Thread the stop screw and jam 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 graduations on the press pin, adjust the stop screw to the depth.
Depth: 60 mm (2.36 inch)





3. Place the base on the 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.

CAUTION: 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.

7. Remove the piston assembly from the base. Remove the guide pin and press pin from the assembly.

]B[ Oil Ring Installation





1. Fit the oil ring spacer into the piston ring groove.

NOTE: The side rails and spacer may be installed in either direction.





NOTE: New spacers and side rails are colored for identification of their sizes.

CAUTION: Do not use any piston ring expander when installing the side rail.





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 the position by finger. See illustration.
Use of a ring expander to expand the side rail end gap can break the side rail, unlike other piston rings.
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.

]C[ Piston Ring No.2/Piston Ring No.1 Installation





1. Using a piston ring expander, fit the number 2 and then number 1 piston ring into position.

NOTE: The ring end is provided with the identification mark.
Number 1 ring: T
Number 2 ring: 2T

NOTE: Install the piston rings with their identification mark facing up, to the piston crown side.





NOTE: Size marks on piston rings are as follows.

]D[ Connecting Rod Bearing Installation














1. From the following table, select a bearing whose size is appropriate for the crankshaft pin outside diameter. If the crankshaft pin outside diameter ID color is "yellow" and the connecting rod ID color is "yellow," for example, select a bearing whose ID color is "black."
If there is no ID color paint on the crankshaft, measure the pin outside diameter and select a bearing appropriate for the measured value.
2. Install the selected bearing in the big end and in the cap of the connecting rod.

]E[ Piston And Connecting Rod Installation
1. Liberally coat the circumference of the piston piston ring, and oil ring with engine oil.





2. Arrange the piston ring and oil ring gaps (side rail and spacer) as shown in the illustration.
3. Rotate the crankshaft so that the crank pin is on the center of the cylinder bore.





4. Insert the piston and connecting rod assembly into the cylinder with the front mark on the piston crown pointing to the timing belt side.





5. Using a suitable piston ring compressor tool, install the piston and connecting rod assembly into the cylinder block.

]F[ Connecting Rod Cap Installation





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 (0.004 - 0.0098 inch)
Limit: 0.4 mm (0.02 inch)

INSPECTION
Piston
Replace the piston if scratches or seizure is evident on its surfaces (especially the thrust surface). Replace the piston if it is cracked.

Piston Pin
1. Insert the piston pin into the piston pin hole with a thumb. You should feel a slight resistance. Replace the piston pin if it can be easily inserted or there is an excessive play.
2. The piston and piston pin must be replaced as an assembly.

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 for clearance between the piston ring and ring groove. If the limit is exceeded, replace the ring or piston, or both.
Standard value:
Number 1 0.03 - 0.07 mm (0.0012 - 0.00027 inch)
Number 2 0.02 - 0.06 mm (0.0008 - 0.0023 inch)
Limit: 0.1 mm (0.003 inch)





3. Insert 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 ring gap is excessive, replace the piston ring.
Standard value:
Number 1: 0.30 - 0.45 mm (0.012 - 0.017 inch)
Number 2: 0.45 - 0.60 mm (0.018 - 0.023 inch)
Oil: 0.20 - 0.60 mm (0.008 - 0.023 inch)
Limit:
Number 1, Number 2: 0.8 mm (0.03 inch)
Oil: 1.0 mm (0.03 inch)

Crankshaft Pin Oil Clearance (Plastic Gauging Material Method)
The crankshaft oil clearance can be measured easily by using plastic gauging material, as follows:
1. Remove oil from the crankshaft pin and the bearing inner surface.
2. Cut plastic gauging material to the same length as the width of the bearing and place it on the 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 smashed plastic gauging material at its widest section by using a scale printed on the plastic gauging material bag.
Standard value: 0.02 - 0.05 mm (0.0008 - 0.0019 inch)
Limit: 0.1 mm (0.003 inch)