Piston and Connecting Rod
PISTON AND CONNECTING RODREMOVAL AND INSTALLATION
Removal Steps 1-14:
Required Special Tools:
^ MB992236: Circlip Installer
^ MD998780: Piston Setting Tool
REMOVAL SERVICE POINTS
[A] CONNECTING ROD REMOVAL
Mark the connecting rod on the big end with the cylinder number it is being removed from.
[B] SNAP RING REMOVAL
Insert the precise screwdriver into the service hole to remove the snap ring.
[C] PISTON PIN REMOVAL
CAUTION:
The clearance between the piston and the piston pin is a tight fit at room temperature. Therefore, be sure the heat the piston before pulling out the piston pin. Use care sine the piston is hot after heating.
1. Into each container, pour enough engine oil to completely cover a piston.
2. Heat the engine oil to warm the piston to approximately 70 degrees C (158 degrees F), and then remove the piston pin.
INSTALLATION SERVICE POINTS
[A] PISTON PIN INSTALLATION
1. When replacing a piston, check the cylinder bore size mark stamped on the illustrated position of the cylinder block and select a corresponding piston from the table below.
NOTE: The piston size mark is indicated on the piston top face.
CAUTION:
The clearance between the piston and the piston pin is a tight fit at room temperature. Therefore, be sure the heat the piston before pulling out the piston pin. Use care sine the piston is hot after heating.
2. Into each container, pour enough engine oil to completely cover a piston.
3. Heat the engine oil to warm the piston to approximately 70 degrees C (158 degrees F), and then remove the piston pin.
4. Sufficiently apply the engine oil to the outer circumference of piston pin and the small end hole of connecting rod.
5. Put the front mark of connecting rod and the front mark of piston toward the same side, and then insert the piston pin.
6. Install the circlip to the piston according to the following procedure:
1) With the open side facing upward, install the new circlip to the special tool MB992236.
2) Align the open side of circlip with the piston groove, and then set the circlip together with the special tool MB992236.
3) Install the guide A (diameter 21.9 mm [0.88 inch]), to the push rod of special tool MD998780.
4) Push the opposite side of open side with the special tool MD998780, and install the circlip to the piston groove.
5) Make sure the circlip is seated into the groove.
6) Unless seated into the groove, the circlip must be pushed with the special tool MD998780 again to be seated into the groove.
7. Check that the piston moves smoothly.
[B] OIL RING INSTALLATION
1. Assemble the spacer of the oil ring into the piston ring groove. Then, assemble the upper side rail, and after this assemble the lower side rail.
NOTE: Install the side rail and end gap of the spacer so that they are at the position as shown in the illustration.
NOTE: New spacers and side rails are an identified by color marks as follows:
CAUTION:
The side rail may be broken if its end gap is widened by a ring expander as in other piston rings.
2. When assembling the side rail, push it by fingers, after fitting one end of the side rail into the piston groove, for easy assembly.
3. After assembling the oil ring into the piston, make sure that the side rail turns smoothly to either direction.
[C] PISTON RING NO. 2 / PISTON RING NO. 1 INSTALLATION
Use a piston ring expander to assemble piston rings with their identification marks facing upward. Piston rings can be assembled by hand without using the piston ring expander.
Identification mark
No. 1 ring: 1R
No. 2 ring: 2R
NOTE: Each of the available piston rings has a size mark as follows:
[D] PISTON CONNECTING ROD ASSEMBLY INSTALLATION
1. Apply a sufficient amount of engine oil to the circumference of the piston, piston rings and oil ring.
2. Arrange end gap positions of piston rings and oil ring (side rail and spacer) as shown in the illustration.
3. Insert the piston and connecting rod assembly from the top surface of the cylinder block with the front mark of the piston top face facing toward the timing chain side.
CAUTION:
Driving it in hard causes breakage of piston rings and damage to the crank pin.
4. Firmly tighten the piston ring with a ring band and insert the piston and connecting rod assembly.
[E] CONNECTING ROD BEARING INSTALLATION
1. When replacing a connecting rod bearing, select the bearing corresponding to the crankshaft pin outside diameter according to the crankshaft pin identification in the table below.
2. An identification mark of a crankshaft is stamped at the illustrated position by No.
3. A connecting rod bearings an identification mark at the illustrated position.
[F] CONNECTING ROD CAP INSTALLATION
1. Assemble the bearing cap on the connecting rod by aligning it with the mark put during removal. If a new connecting rod without a mating mark is used, assemble so that the detent notch of the bearing is on the same side as illustrated.
2. Make sure that clearance of the thrust of the connecting rod big end is appropriate.
Standard value: 0.10 -0.25 mm (0.004 -0.010 inch)
Limit: 0.4 mm (0.02 inch)
[G] CONNECTING ROD CAP BOLT INSTALLATION
1. Check in the following procedure before reusing the connecting rod bolt.
1) Measure the outside diameter "A."
2) Measure the smallest outside diameter "B" within the range "X" shown in the illustration.
3) If the difference of outside diameter of thread exceeds the limit, replace the connecting rod bolt.
Limit: 0.10 mm (0.004 inch)
2. Apply engine oil to the threaded portion and seat surface of the bolt before installing it.
3. After installing each bolt and tightening it by fingers, tighten bolts alternately to properly assemble the cap.
4. Tighten the bolt in several steps until the torque reaches 5.0 Nm (44 in-lb).
5. Tighten the bolt in several steps until the torque reaches 20 Nm (15 ft-lb).
6. Put a paint mark on the bolt head as illustrated.
7. Put a paint mark on the connecting rod at 90 degrees position in the tightening direction of the bolt with reference to the paint mark position of the bolt.
CAUTION:
^ When the tightening angle is smaller than the specified tightening angle, the appropriate tightening capacity cannot be secured.
^ When the tightening angle is larger than the specified tightening angle, remove the bolt to start from the beginning again according to the procedure.
8. Tighten the bolt 90 degrees, and make sure that the paint mark of the connecting rod is aligned with that of the bolt.
INSPECTION
PISTON RINGS
1. Check clearance between piston rings and ring grooves. If the limit is exceeded, replace piston rings or piston, or both.
Standard value:
No. 1 ring: 0.02 -0.06 mm (0.001 -0.002 inch)
No. 2 ring: 0.02 -0.06 mm (0.001 -0.002 inch)
Limit: 0.10 mm (0.004 inch)
2. Put piston rings into the cylinder bore, press them against the piston top face, and push them in. After achieving squareness, measure the end gap with a thickness gauge. If the end gap is excessive, replace piston rings.
Standard value:
No. 1 ring: 0.18 -0.28 mm (0.007 -0.011 inch)
No. 2 ring: 0.28 -0.43 mm (0.011 -0.017 inch)
Oil ring: 0.10 -0.34 mm (0.004 -0.013 inch)
Limit:
No. 1 ring: 0.8 mm (0.03 inch)
No. 2 ring: 0.8 mm (0.03 inch)
Oil ring: 1.0 mm (0.04 inch)
CRANKSHAFT PIN OIL CLEARANCE (PLASTIGAGE METHOD)
1. Wipe oil off the crankshaft pin and connecting rod bearing.
2. Place a plastigage in length equal to the bearing width on the pin shaft straight in alignment with the shaft center.
3. Carefully install the connecting rod cap and tighten bolts to the specified torque of 5.0 Nm (44 in-lb) ->20 Nm (15 ft-lb) ->+ 90 degrees.
4. Remove bolts and gently remove the connecting rod cap.
5. Measure the crushed plastigage width (area most widely crushed) using a scale printed on the plastigage bag.
Standard value: 0.038 -0.069 mm (0.0015 -0.0027 inch)
Limit: 0.10 mm (0.004 inch)