Piston Pin: Service and Repair

REMOVAL
1. Follow the removal procedure outlined in the illustration, noting the following.





2. Mark the large end of the connecting rod with the cylinder number for further reassembly.

INSTALLATION
1. Follow the removal procedure in reverse order, noting the following.
2. Coat a large amount of engine oil on the circumference of the piston, piston ring, and oil ring.





3. Arrange the piston ring and oil ring gaps (side rail and spacer) as shown in the figure.
4. Rotate crankshaft so that crank pin is on center of cylinder bore.
5. Use suitable thread protectors on connecting rod bolts before inserting piston and connecting rod assembly into cylinder block. Do not nick crank pin.
6. Use a suitable piston ring compressor tool to install piston and connecting rod assembly into cylinder block.





CAUTION: Insert the front mark (arrow) on the top of the piston so it faces the engine front (timing belt side).

7. When replacing the bearing, choose a bearing as follows.








a. Measure the diameter of the crankshaft pin and then understand which class the pin belongs to in the illustration. In addition, a service part has its own identification color as shown in the illustration.








b. The illustration shows an identification mark of a connecting rod bearing.
c. Choose a bearing according to the illustration.

Example
If the measured value of a crankshaft pin outer diameter is between 44.995 - 45.000 mm (1.7715 - 1.7717 inch), the pin is classified as "A" in the table. In case the crankshaft is also replaced by a spare part, check the identification colors of the pins painted on the new crankshaft. For example, if the color is yellow, the pin is classified as "A". In the above cases, select the connecting rod bearing having identification mark"1".





8. 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.





9. Check if the thrust clearance is 0.10 - 0.25 mm (0.0039 - 0.0098 inch) in the connecting rod big end is correct. The wear limit is 0.4 mm (0.016 inch).

NOTE: Remove the cylinder head or spark plug to loosen the connecting rod nuts.

10. Since the connecting rod bolts and nuts are torqued using a new procedure, examine them BEFORE reuse. If the bolt threads are "necked down", replace the bolts. Necking can be checked by running a nut with fingers to the full length of the bolt's thread. If the nut does not run down smoothly, replace the bolt.
11. Before installing the nuts, the threads should be oiled with engine oil.
12. Install both nuts on each bolt finger tight, then alternately torque each nut to assemble the cap properly.
13. Tighten the nuts to 20 Nm (14.5 ft. lbs.).





14. Paint a mark on the nut head.
15. Use the painted mark as a reference to paint a mark on the bolt in a position 90° - 100° in the tightening direction of the nut.

CAUTION:
a. If the tightening angle is less than 90°, the bolt will be loosened. Be careful to observe the tightening angle.
b. If the tightening angle is more than 100°, remove the nut and repeat the procedure from step 10.

16. Tighten the nuts 90° - 100° and then check that the painted mark on the nuts is aligned with that on the bolts.