Cylinder Block: Inspection

PISTON AND PISTON PIN CLEARANCE 

Inner Diameter of Piston Pin Hole 

• Measure the inner diameter of piston pin hole using suitable tool (A).

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  Standard

  : Refer to Cylinder Block .

Outer Diameter of Piston Pin 

• Measure outer diameter of piston pin using suitable tool (A).

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  Standard

  : Refer to Cylinder Block .

Piston and Piston Pin Interference Fit 

(Piston to piston pin oil clearance) = (Piston pin hole diameter) - (Piston pin outer diameter)

Standard

: Refer to Cylinder Block .

• If clearance is exceeds specification, replace either or both of piston/piston pin assembly and connecting rod assembly with reference to specification of each part.

PISTON RING SIDE CLEARANCE 

• Measure side clearance of piston ring and piston ring groove using suitable tool (C).

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Standard and Limit

: Refer to Cylinder Block .

(A)	: OK
(B)	: NG

• If out of specification, replace piston ring assembly. If clearance exceeds maximum limit with new rings, replace piston.

PISTON RING END GAP 

• Using piston (1), insert (A) piston ring (2) until it is in the middle of the cylinder bore and measure the end gap using suitable tool (B).

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Standard and Limit

: Refer to Cylinder Block .

• If measured value exceeds limit replace piston ring and measure again. If it still exceeds the limit replace cylinder block.

CONNECTING ROD BEND AND TORSION 

• Check wit a connecting rod aligner.

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  Limit

  : Refer to Cylinder Block .

• If it exceeds the limit, replace connecting rod assembly.

CONNECTING ROD BEARING HOUSING DIAMETER (BIG END) 

• Install the connecting rod cap (1) without the connecting rod bearing installed and tighten the connecting rod bolts. Refer to Disassembly and Assembly .

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  (2)	: Connecting rod
  (A)	: Measuring direction of inner diameter

• Measure inner diameter of connecting rod (big end) using a suitable tool.

  Standard

  : Refer to Cylinder Block .

• If it exceeds the standard, replace connecting rod assembly.

CONNECTING ROD BUSHING OIL CLEARANCE (SMALL END) 

Inner Diameter of Connecting Rod (Small End) 

• Measure inner diameter of piston pin bushing using suitable tool (A).

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  Standard

  : Refer to Cylinder Block .

Outer Diameter of Piston Pin 

• Measure outer diameter of piston pin using suitable tool (A).

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  Standard

  : Refer to Cylinder Block .

Connecting Rod Bushing Oil Clearance (Small End) 

(Connecting rod small end oil clearance) = (Inner diameter of connecting rod small end) - (Outer diameter of piston pin)

Standard and Limit

: Refer to Cylinder Block .

• If the measured value exceeds the standard, replace the connecting rod assembly and/or piston and piston pin assembly.
• If replacing the piston and piston pin assembly, use the Table for Selective Fitting for Piston to select the piston corresponding to the applicable bore grade of the cylinder block to be used. Follow the "PISTON-TO-CYLINDER BORE CLEARANCE" procedure.

CYLINDER BLOCK DISTORTION 

• Using a suitable tool, remove any old gasket material on the cylinder block surface and remove any engine oil, scale, carbon, or other contamination.
  CAUTION:

  Be careful not to allow gasket flakes to enter the engine oil or engine coolant passages.

• Measure distortion on cylinder block upper face at some different points in six directions using suitable tools (A/B).

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Limit

: Refer to Cylinder Block .

• If out of specification, resurface the cylinder block. The allowable amount of resurfacing is dependent on the amount of any cylinder head resurfacing. The resurfacing limit is [amount of cylinder head resurfacing] + [amount of cylinder head resurfacing] = 0.2 mm (0.008 in).

  Cylinder block height

  : 214.95 - 215.05 mm (8.4626 - 8.4665 in)

INNER DIAMETER OF MAIN BEARING HOUSING 

• Install the main bearing caps with the main bearings removed, and tighten the bolts to the specified torque.

• Using suitable tool, measure the inner diameter (A) of the main bearing housing.

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Standard

: Refer to Cylinder Block .

• If out of the standard, replace the cylinder block and main bearing caps as an assembly.
  NOTE: These components cannot be replaced as a single unit, because they were processed together.

PISTON-TO-CYLINDER BORE CLEARANCE 

1. Using suitable tool, measure cylinder bore for wear, out-of-round and taper at (C), (D) and (E). The (A) axis is in the longitudinal direction of the engine.

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   Out-of-round [Difference between (A) and (B) ]
   Limit	: Refer to Cylinder Block .
   Taper [Difference between (C), (D) and (E) in direction (A) ]
   Limit	: Refer to Cylinder Block .

   (F)	: 120 mm (4.72 in)
   (G)	: 60 mm (2.36 in)
   (H)	: 10 mm (0.39 in)

   If it exceeds the limit, rebore all cylinders. Replace cylinder block if necessary.

2. Check for scratches or other damage. If scratches or damage found, hone it.
   • If both cylinder block and piston are replaced with new ones, select piston of the same grade number punched on cylinder block rear position. These numbers are punched in either Arabic or Roman numerals. 

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     (A)	: Cylinder bore grade
     (B)	: Main journal grade
     (C)	: Management code

3. Measure piston skirt diameter, using suitable tool.

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   Cylinder Block 

   Piston diameter (A)	: Refer to Cylinder Block .
   Measuring point (a) (Distance from the top)	: 38.0 mm (1.496 in)

4. Check that piston-to-bore clearance is within specification.
   • Calculate by piston skirt diameter and cylinder bore inner diameter [direction (B), position (D) ].

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     (Clearance) = (Cylinder bore inner diameter) - (Piston skirt diameter)
     Standard	: Refer to Cylinder Block .

     (A)	: Used for measuring cylinder bore out-of-round
     (C)	: Used for measuring cylinder bore taper
     (E)	: Used for measuring cylinder bore taper
     (F)	: 120 mm (4.72 in)
     (G)	: 60 mm (2.36 in)
     (H)	: 10 mm (0.39 in)

Re-boring Cylinder Bore 

1. Cylinder bore size is determined by adding piston-to-bore clearance to piston diameter.

   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 in)

2. Install main bearing caps and main bearing beam, and tighten to the specified torque. Otherwise, cylinder bores may be distorted after boring. Refer to Exploded View .
3. 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 in) or so in diameter at a time. 
4. Hone cylinders to obtain specified piston-to-bore clearance.
5. Measure finished cylinder bore for out-of-round and taper.
   • Measurement should be done after cylinder bore cools down. 

CRANKSHAFT 

1. Check the crankshaft main and pin journals for scoring, wear, or cracks.

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2. Measure the journals for taper and out-of-round.

   Standard
   Out-of-round [ (X) - (Y) ]	: Refer to Cylinder Block .
   Taper [ (A) - (B) ]	: Refer to Cylinder Block .

3. Measure crankshaft runout.

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   Place a V-block on a precise flat table to support the journals on the both ends of the crankshaft. Place a dial gauge straight up on the No. 3 journal. While rotating the crankshaft, read the movement of the pointer on the dial gauge.

   Runout (total indicator reading)
   Standard and Limit	: Refer to Cylinder Block .

BEARING CLEARANCE 

• Use either of the following two methods, however method (A) gives more reliable results and so is the preferred method.

Method A (Using Bore Gauge and Micrometer 

Main Bearing 

1. Set the main bearings in their proper positions on the cylinder block and the main bearing cap.
   NOTE: Main bearing (upper) have an oil groove and the main bearing (lower) do not have an oil groove.
2. Install the main bearing caps and bearing beam to the cylinder block. Tighten all bolts to the specified torque in the sequence shown. Refer to Disassembly and Assembly .
3. Measure the inner diameters (A) of each main bearing as shown, below.

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4. Using suitable tool (A), measure the outer diameters of each crankshaft main journal as shown, below.

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5. Calculate the main bearing clearance. Main bearing clearance = (Main bearing inner diameter) - (Crankshaft journal diameter)

   Standard and Limit

   : Refer to Main Bearing .

   • If it exceeds the limit, replace the main bearing.
   • If clearance cannot be adjusted using any standard bearing grade, grind crankshaft journal and use an undersized bearing.
   • When grinding the crankshaft journal, confirm that the (L) dimension in the fillet role is more than the specified limit.

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     Limit

     : Refer to Cylinder Block .

6. If the crankshaft or the cylinder block is replaced with a new one, select thickness of the main bearings as follows: The grade number of each cylinder block main journal (B) is punched on the respective cylinder block. These numbers are punched in either Arabic or Roman numerals. If measured diameter is out of the grade punched, decide suitable grade from available main bearings.

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   (A)	: Cylinder bore grade
   (C)	: Management code

   The grade number of each crankshaft main journal (A) is punched on the crankshaft end. These numbers are punched in either Arabic or Roman numerals. If measured diameter is out of grade punched, decide the suitable grade from available main bearings.

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   (B)	: Crankshaft pin journal grade
   (C)	: Production mark area

   Select the main bearing suitable thickness according to the following table:

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   (A)	: Mark
   (B)	: Cylinder block bearing housing inner diameter
   (C)	: Crankshaft main journal diameter
   (D)	: Journal diameter [Unit: mm (in) ]
   (E)	: Bore diameter [Unit: mm (in) ]

Connecting Rod Bearing (Big End) 

1. Install connecting rod bearings (2) to connecting rod (3) and connecting rod bearings cap (1) and tighten connecting rod bolts. Refer to Disassembly and Assembly .

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2. Measure the inner diameter (A) of each connecting rod (big end) as shown, below.
3. Using suitable tool (A), measure the outer diameter of each crankshaft pin journal.

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4. Calculate the connecting rod bearing clearance. (Bearing oil clearance) = (Connecting rod bearing inner diameter) - (Crankshaft pin journal diameter)

   Standard and Limit

   : Refer to Connecting Rod Bearing .

5. If the calculated clearance exceeds the specified limit, replace the bearings.
6. If the clearance cannot be adjusted within the standard of any bearing, grind the crankshaft journal and use undersized bearings.
7. If the crankshaft is replaced with a new one, select the connecting rod bearings according to the following table:

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   Connecting Rod Bearing Grade Number (Identification Color) 

   Crankshaft pin journal grade number	Connecting rod bearing grade number
   0	0 (black - black)
   1	1 (brown - brown)
   2	2 (green - green)

   These numbers are punched in either Arabic or Roman numerals.

Method B (Using Plastigage) 

• Remove engine oil and dust on the crankshaft pin and the surfaces of each bearing completely.

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• Cut a Plastigage slightly shorter than the bearing width, and place it in crankshaft axial direction, avoiding oil holes.

• Install the connecting rod bearings to the connecting rod cap, and tighten the connecting rod bolts to the specified torque. Refer to Disassembly and Assembly .
  CAUTION:

  Do not rotate the crankshaft.

• Remove the connecting rod cap and bearings, and using the scale on the Plastigage bag, measure the Plastigage width.
  NOTE: The procedure when the measured value exceeds the repair limit is same as that described in "Method A (Using Bore Gauge and Micrometer) ".

OIL JET 

• Check nozzle for deformation and damage.
• Blow compressed air from nozzle, and check for clogs.
• If it is not operating properly, replace oil jet.