Disassembly and Inspection
CAUTION:
- When installing bearings, pistons, or other sliding parts, lubricate contacting surfaces with new engine oil.
- 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 signal plate teeth of flywheel or drive plate.
DISASSEMBLY
Piston And Crankshaft
1. Place engine on a work stand.
2. Remove timing chain.
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 replacing piston rings, if there is no punch-mark, install with either side up.
4. Remove main bearing beam and crankshaft.
- Before removing main bearing beam, measure crankshaft end play.
- Bolts should be loosened in two or three steps.
INSPECTION
Piston And Piston Pin Clearance
1. Measure inner diameter of piston pin hole "dp".
Standard diameter "dp": 20.987 - 20.999 mm (0.8263 - 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 piston pin clearance.
dp - Dp = -0.004 to 0 mm (-0.0002 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)
Max. Limit of side clearance: 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)
Max. Limit of ring gap: 1.0 mm (0.039 inch)
If out of specification, replace piston ring. If gap still exceeds the limit even with a new ring, do the following: 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 And Wear
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 the image.
Distortion limit: 0.10 mm (0.0039 inch)
- If out of specification, resurface it. The limit for cylinder block resurfacing is determined by cylinder head resurfacing in engine.
Resurfacing limit:
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)
- 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 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: 0.015 mm (0.0006 inch)
Taper (A - B) standard: 0.01 mm (0.0004 inch)
2. Check for scratches and seizure. If seizure is found, hone it.
- If both cylinder block and pistons are replaced with new ones, select pistons of the same grade numbers as those punched on cylinder block upper surface.
3. Measure piston skirt diameter.
Piston diameter"A":
Measuring point "a" (Distance from the top): 52 mm (2.05 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.
6. Cylinder bore size is determined by adding piston-to-bore clearance 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 bolts to the specified torque. This will prevent distortion of cylinder bores.
- Otherwise, cylinder bores may be distorted in final assembly.
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 in diameter 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
1. Check crankshaft main and pin journals for score, wear or cracks.
2. With a micrometer, measure journals for taper and out-of-round.
Out-of-round (X - Y): Less than 0.005 mm (0.0002 inch)
Taper (A - B): Less than 0.002 mm (0.0001 inch)
3. Measure crankshaft runout.
Runout (Total indicator reading): Less than 0.04 mm (0.0016 inch)
Bearing Clearance
Use either of the following two methods. However, method "A" gives more reliable results and is preferred.
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 journal and use undersized bearing.
a. When grinding crankshaft journal, confirm that "L" dimension in fillet roll is more than the specified limit.
"L": 0.1 mm (0.004 inch)
6. If crankshaft is reused, measure main bearing clearance and select thickness of main bearings.
If crankshaft is replaced with a new one, 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.
Connecting Rod Bearing (Big End)
1. Install connecting rod bearing to connecting rod and 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 within the standard of any bearing, grind crankshaft journal and use undersized bearing.
6. If crankshaft is replaced with a new one, select connecting rod bearing according to the following table.
Method B (Using Plastigage)
CAUTION:
- Do not turn crankshaft or connecting rod while plastigage is being inserted.
- If incorrect bearing clearance exists, use a thicker or undersized main bearing to ensure specified clearance.
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.
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 until clearance with piston pin is within specification.
Clearance between connecting rod 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 0.5 mm (0.020 inch)
CAUTION:
- Be careful not to damage the ring gear teeth.
- Check the drive plate for deformation or cracks.
- Do not allow any magnetic materials to contact the ring gear teeth.
- Do not surface flywheel. Replace as necessary.