Cylinder Block Assembly: Service and Repair
Disassembly
CAUTION:
- When installing sliding parts such as bearings and pistons, apply new engine oil on the sliding surfaces.
- Place removed parts such as bearings and bearing caps in their proper order and direction.
- When installing connecting rod nuts and main bearing cap bolts, apply new engine oil to threads and seating surfaces.
- Do not allow any magnetic materials to contact the ring gear teeth of flywheel or drive plate.
PISTON AND CRANKSHAFT
1. Place engine on a work stand.
2. Remove timing chains.
Piston Heater
Piston Press
3. Remove pistons with connecting rods.
- To disassemble piston and connecting rod, first remove snap rings. Heat piston to 60 to 70°C (140 to 158°F) then use piston pin press to remove pin.
CAUTION:
- When piston rings are not replaced, make sure that piston rings are mounted in their original positions.
- When piston rings are being replaced and no punchmark is present, piston rings can be mounted with either side up.
4. Remove main bearing cap and crankshaft.
- Before removing main bearing cap, measure crankshaft end play.
- Bolts should be loosened in two or three steps in numerical order as shown.
Inspection
PISTON AND PISTON PIN CLEARANCE
1. Measure inner diameter of piston pin hole "dp".
Standard diameter "dp": 20.993 - 20.999 mm (0.8265 - 0.8267 inch)
2. Measure outer diameter of piston pin "Dp".
Standard diameter "Dp": 20.989 - 21.001 mm (0.8263 - 0.8268 inch)
3. Calculate interference fit of piston pin to piston.
Dp - dp: -0.002 to 0.01 mm (-0.0001 to 0 inch)
If it exceeds the above value, replace piston assembly with pin.
PISTON RING SIDE CLEARANCE
Side clearance:
Top ring 0.040 - 0.080 mm (0.0016 - 0.0031 inch)
2nd ring 0.030 - 0.070 mm (0.0012 - 0.0028 inch)
Oil ring 0.065 - 0.135 mm (0.0026 - 0.0053 inch)
Maximum limit of side clearance for top and 2nd rings: 0.1 mm (0.004 inch)
If Out of specification, replace piston ring. If clearance exceeds maximum limit with new ring, replace piston.
PISTON RING END GAP
End gap:
Top ring 0.28 - 0.52 mm (0.0110 - 0.0205 inch)
2nd ring 0.45 - 0.69 mm (0.0177 - 0.0272 inch)
Oil ring 0.20 - 0.69 mm (0.0079 - 0.0272 inch)
Maximum limit of end gap: 1.0 mm (0.039 inch)
If out of specification, replace piston ring. If gap exceeds maximum limit with new ring, rebore cylinder and use oversized piston and piston rings.
When replacing the piston, check the cylinder block surface for scratches or seizure. If scratches or seizure are found, hone or replace the cylinder block.
CONNECTING ROD BEND AND TORSION
Bend:
Limit 0.15 mm (0.0059 inch) per 100 mm (3.94 inch) length
Torsion:
Limit 0.30 mm (0.0118 inch) per 100 mm (3.94 inch) length If it exceeds the limit, replace connecting rod assembly.
CYLINDER BLOCK DISTORTION
1. Clean upper surface of cylinder block. Use a reliable straightedge and feeler gauge to check the flatness of cylinder block surface. Check along six positions shown in figure.
Block surface flatness:
Standard: Less than 0.03 mm (0.0012 inch)
Limit: 0.10 mm (0.0039 inch)
2. If out of specification, resurface it.
Resurfacing limit:
The limit for cylinder block resurfacing is determined by the cylinder head resurfacing.
Amount of cylinder head resurfacing is "A".
Amount of cylinder block resurfacing is "B".
The maximum limit is as follows: A + B = 0.2 mm (0.008 inch)
Nominal cylinder block height from crankshaft center: 246.95 - 247.05 mm (9.7224 - 9.7264 inch)
3. If necessary, replace cylinder block.
PISTON-TO-BORE CLEARANCE
1. Using a bore gauge, measure cylinder bore for wear, out of-round and taper.
Standard inner diameter: 89-000 - 89.030 mm (3.5039 - 3.5051 inch)
Wear limit: 0.2 mm (0.008 inch)
If it exceeds the limit, rebore all cylinders. Replace cylinder block if necessary.
Out-of-round (X - Y) standard: Less than 0.015 mm (0.0006 inch)
Taper (A - B) standard: Less than 0.01 mm (0.0004 inch)
2. Check for scratches and seizure. If seizure is found, hone it.
- If cylinder block and piston are replaced, match piston grade with grade number on cylinder block surface.
3. Measure piston skirt diameter.
Piston diameter "A": Refer to Engine; Specifications.
Measuring point "a" (Distance from the top): Approximately 48 mm (1.89 inch)
4. Check that piston-to-bore clearance is within specification.
Piston-to-bore clearance "B": 0.020 - 0.040 mm (0.0008 - 0.0016 inch)
5. Determine piston oversize according to amount of cylinder wear.
Oversize pistons are available for service. Refer to Engine; Specifications.
6. Cylinder bore size is determined by adding piston-to-bore clearance "B" to piston diameter "A".
Rebored size calculation: D = A + B - C where,
D: Bored diameter
A: Piston diameter as measured
B: Piston-to-bore clearance
C: Honing allowance 0.02 mm (0.0008 inch)
7. Install main bearing caps and tighten to the specified torque. This will prevent distortion of cylinder bores.
8. Cut cylinder bores.
- When any cylinder needs boring, all other cylinders must also be bored.
- Do not cut too much out of cylinder bore at a time. Cut only 0.05 mm (0.0020 inch) or so at a time.
9. Hone cylinders to obtain specified piston-to-bore clearance.
10. Measure finished cylinder bore for out-of-round and taper.
- Measurement should be done after cylinder bore cools down.
CRANKSHAFT
- Check crankshaft main and pin journals for score, wear or cracks.
- With a micrometer, measure journals for taper and out-of round.
Out-of-round (X - Y):
Main 0.01 mm (0.0004 inch)
Pin 0.005mm (0.0002 inch)
Taper (A - 13):
Main 0.01 mm (0.0004 inch)
Pin 0.005 mm (0.0002 inch)
- Measure crankshaft runout.
Runout (Total indicator reading): 0.10 mm (0.0039 inch)
BEARING CLEARANCE
- Use Method A or Method B. Method A is preferred because it is more accurate.
Method A (Using bore gauge & micrometer)
Main bearing
1. Set main bearings in their proper positions on cylinder block and main bearing cap.
2. Install main bearing cap to cylinder block.
- Tighten all bolts in correct order in two or three stages.
3. Measure inner diameter "A" of each main bearing.
4. Measure outer diameter "Dm" of each crankshaft main journal.
5. Calculate main bearing clearance.
Main bearing clearance = A - Dm
Standard: 0.020 - 0.047 mm (0.0008 - 0.0019 inch)
Limit: 0.1 mm (0.004 inch)
If it exceeds the limit, replace bearing.
If clearance cannot be adjusted using any standard bearing grade, grind crankshaft main journal and use undersized bearing.
When grinding crankshaft journal, confirm that "L" dimension in fillet roll is more than the specified limit.
"L": 0.1 mm (0.004 inch)
For grinding crankshaft and available service parts, refer to Engine; Specifications.
- If crankshaft is replaced, select thickness of main bearings as follows:
a. Grade number of each cylinder block main journal is punched on the respective cylinder block. These numbers are punched in either Arabic or Roman numerals.
b. Grade number of each crankshaft main journal is punched on crankshaft. These numbers are punched in either Arabic or Roman numerals.
c. Select main bearing with suitable thickness according to the following table.
Main bearing grade number
For example:
Cylinder block main journal grade number: 1
Crankshaft main journal grade number: 2
Main bearing grade number = 1 + 2 = 3 (Yellow)
Connecting rod bearing (Big end)
1. Install connecting rod bearing to connecting rod and connecting rod cap.
2. Install connecting rod cap to connecting rod.
- Tighten bolts to the specified torque.
3. Measure inner diameter "C" of each bearing.
4. Measure outer diameter "Dp" of each crankshaft pin journal.
5. Calculate connecting rod bearing clearance.
Connecting rod bearing clearance = C - Dp
Standard: 0.010 - 0.035 mm (0.0004 - 0.0014 inch)
Limit: 0.09 mm (0.0035 inch)
If it exceeds the limit, replace bearing.
If clearance cannot be adjusted using any standard bearing grade, grind crankshaft pin journal and use undersized bearing.
- If crankshaft is replaced with a new one, select connecting rod bearings according to the following table.
Connecting rod bearing grade number
These numbers are punched in either Arabic or Roman numerals.
Method B (Using plastigage)
CAUTION:
- Do not turn crankshaft or connecting rod while plastigage is being inserted.
- When bearing clearance exceeds the specified limit, ensure that the proper bearing has been installed. Then if excessive bearing clearance exists, use a thicker main bearing or undersized bearing so that the specified bearing clearance is obtained.
CONNECTING ROD BUSHING CLEARANCE (Small end)
1. Measure inner diameter "C" of bushing.
2. Measure outer diameter "Dp" of piston pin.
3. Calculate connecting rod bushing clearance.
C - Dp = 0.005 - 0.017 mm (0.0002 - 0.0007 inch) (Standard) 0.023 mm (0.0009 inch) (Limit)
If it exceeds the limit, replace connecting rod assembly and/or piston set with pin.
REPLACEMENT OF CONNECTING ROD BUSHING (Small end)
1. Drive in small end bushing until it is flush with end surface of rod.
Be sure to align the oil holes.
2. Ream the bushing so that clearance with piston pin is within specification.
Clearance between small end bushing and piston pin: 0.005 - 0.017 mm (0.0002 - 0.0007 inch)
FLYWHEEL/DRIVE PLATE RUNOUT
Runout (Total indicator reading):
Flywheel (M/T model) Less than 0.15 mm (0.0059 inch)
Drive plate (A/T model) Less than 0.15 mm (0.0059 inch)
CAUTION:
- Be careful not to damage the ring gear teeth.
- Check drive plate for deformation and cracks.
- Do not allow any magnetic materials to contact the ring gear teeth.
- Do not resurface the flywheel. Replace as necessary.
Assembly
PISTON
1. Install new snap ring on one side of piston pin hole.
2. Heat piston to 60 to 70°C (140 to 158°F) and assemble piston, piston pin, connecting rod and new snap ring.
- Align the direction of piston and connecting rod.
- Numbers stamped on connecting rod and cap correspond to each cylinder.
- After assembly, make sure connecting rod swings smoothly.
3. Set piston rings as shown.
CAUTION:
- When piston rings are not being replaced, make sure that piston rings are mounted in their original positions.
- When piston rings are being replaced and no punchmark is present, piston rings can be mounted with either side up.
- Align piston rings so that end gaps are positioned as shown.
CRANKSHAFT
1. Set main bearings in their proper positions on cylinder block and main bearing cap.
- Confirm that correct main bearings are used.
- Apply new engine oil to bearing surfaces.
2. Install crankshaft and main bearing cap and tighten bolts to the specified torque.
- Apply new engine oil to bolt threads and seat surfaces.
- Prior to tightening bearing cap bolts, shift crankshaft back and forth to properly seat the bearing cap.
- Tighten bearing cap bolts gradually in two or three stages. Start with center bearing and move outward as shown in figure.
- After securing bearing cap bolts, make sure crankshaft turns smoothly by hand.
3. Measure crankshaft end play.
Crankshaft end play: Standard 0.05 - 0.18 mm (0.0020 - 0.0071 inch)
Limit 0.3 mm (0.012 inch)
If beyond the limit, replace bearing with a new one.
4. Install connecting rod bearings in connecting rods and connecting rod caps.
- Confirm that correct bearings are used.
- Install bearings so that oil hole in connecting rod aligns with oil hole of bearing.
- Apply new engine oil to bearing surfaces, bolt threads and seating surfaces.
5. Install pistons with connecting rods.
a. Install them into corresponding cylinders with Tool.
- Be careful not to scratch cylinder wall with connecting rod.
- Arrange so that front mark on piston head faces toward engine front.
- Be careful not to scratch crankshaft journals with connecting rod bolts.
- Apply new engine oil to piston rings and sliding surface of piston.
b. Install connecting rod bearing caps.
Apply new engine oil to threads and seat surfaces.
Tighten connecting rod bearing cap nuts in the following procedure:
1) Tighten to 14 to 16 Nm (1.4 to 1.6 kg-m, 10 to 12 ft. lbs.).
2) Turn all nuts 60 to 65 degrees clockwise. If an angle wrench is not available, mark all connecting rod bearing cap nuts on the side facing engine front. Then, turn each nut 60 to 65 degrees clockwise.
6. Measure connecting rod side clearance.
Connecting rod side clearance:
Standard 0.2 - 0.4 mm (0.008 - 0.016 inch)
Limit 0.6 mm (0.024 inch)
If beyond the limit, replace connecting rod and/or crankshaft.
REPLACING PILOT BUSHING
1. Remove pilot bushing (M/T) or pilot converter (A/T).
2. Install pilot bushing (M/T) or pilot converter (A/T).