How To Select Piston And Bearing

DESCRIPTION 

Selection points	Selection parts	Selection items	Selection methods
Between cylinder block to crankshaft	Main bearing	Main bearing grade (bearing thickness)	Determined by match of cylinder block bearing housing grade (inner diameter of housing) and crankshaft journal grade (outer diameter of journal)
Between crankshaft to connecting rod	Connecting rod bearing	Connecting rod bearing grade (bearing thickness)	Combining service grades for connecting rod big end inner diameter and crankshaft pin outer diameter determine connecting rod bearing selection
Between cylinder block to piston	Piston and piston pin assembly (The piston is available together with piston pin as an assembly)	Piston grade (piston outer diameter)	Piston grade = cylinder bore grade (inner diameter of bore)
*Between piston to connecting rod	--	--	--

*For the service parts, the grade for fitting cannot be selected between a piston pin and a connecting rod. (Only 0 grade is available.) The information at the shipment from the plant is described as a reference.

• The identification grade stamped on each part is the grade for the dimension measured in new condition. This grade cannot apply to reused parts.

• For reused or repaired parts, measure the dimension accurately. Determine the grade by comparing the measurement with the values of each selection table.

• For details of the measurement method of each part, the reuse standards, and the selection method of the selective fitting parts, follow the applicable procedures.

HOW TO SELECT A PISTON 

• Check the cylinder bore grade on rear left side of cylinder block, and select a piston of the same grade.

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  (A)	: Piston grade ID stamp
  (B)	: Piston crown ID stamp
  (C)	: Front mark

• If there is a corrected stamp mark on the cylinder block, use it as a correct reference.

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  (A)	: Corrected journal machining grade
  (B)	: Corrected bore machining grade
  (C)	: Base bore machining grade
  (D)	: Base journal machining grade

1. Measure the cylinder block bore inner diameter.
2. Determine the bore grade by comparing the measurement with the values under the cylinder bore inner diameter of the "Piston Selection Table". Select the piston of the same grade.

• For the piston selection table, refer to PISTON, PISTON RING, AND PISTON PIN : Service Data .

HOW TO SELECT A CONNECTING ROD BEARING 

1. Apply big end inside diameter grade stamped on connecting rod side face to the row in the "Connecting Rod Bearing Selection Table".

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   (A)	: Oil splash
   (B)	: Small end diameter grade
   (C)	: Reference code
   (D)	: Bearing stopper groove
   (E)	: Reference code
   (F)	: Cylinder No.
   (G)	: Big end diameter grade

2. Apply pin diameter grade (B) stamped on crankshaft front side to the column in the "Connecting Rod Bearing Selection Table".

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   • Journal diameter grade (A)
3. Read the symbol at the cross point of selected row and column in the "Connecting Rod Bearing Selection Table".
4. Apply the symbol obtained to connecting rod bearing grade table to select.

1. Measure dimensions of the big end inner diameter of connecting rod and outer diameter of crankshaft pin individually.
2. Apply the dimension measured to the "Connecting Rod Bearing Selection Table" below.

   Connecting Rod Bearing Selection Table 

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   Connecting Rod Bearing Grade Table. Refer to CONNECTING ROD : Service Data .

• When the specified oil clearance is not obtained with standard size connecting rod bearing, use undersize (US) bearing.

• When using undersize bearing, measure the bearing inner diameter with bearing installed, and grind the crankshaft pin so that the oil clearance satisfies the standard.

Bearing Undersize Table 

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Unit: mm (in)

Size U.S.	Thickness
0.25 (0.0098)	1.622 - 1.630 (0.0639 - 0.0642)

HOW TO SELECT A MAIN BEARING 

1. "Main Bearing Selection Table" rows correspond to bearing housing grade on rear left side of cylinder block.

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   (A)	: Corrected journal machining grade
   (B)	: Corrected bore machining grade
   (C)	: Base bore machining grade
   (D)	: Base journal machining grade

   • If there is a corrected stamp mark on the cylinder block, use it as a correct reference.
2. Apply journal diameter grade (A) stamped on crankshaft front side to column in "Main Bearing Selection Table".

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   (B)	: Pin diameter grade

3. Find value at crossing of row and column in "Main Bearing Selection Table".
4. Apply the symbol obtained to "Main Bearing Grade Table" to select.
   NOTE:

   • Service parts are available as a set of both upper and lower.

1. Measure inner diameter of cylinder block main bearing housing and outer diameter of crankshaft journal.
2. Apply measurement in above step 1 to the "Main Bearing Selection Table".
3. Follow steps 3 and 4 in "When New Cylinder Block and Crankshaft are Used".

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Main Bearing Grade Table (All Journals), refer to MAIN BEARING : Service Data .

• Use undersize (U.S.) bearing when oil clearance with standard size main bearing is not within specification.

• When using undersize (U.S.) bearing, measure the bearing inner diameter with the bearing installed and grind journal until oil clearance falls within specification.

Bearing Undersize Table 

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Unit: mm (in)

Size U.S.	Thickness
0.25 (0.0098)	2.106 - 2.114 (0.0829 - 0.0832)