How to Select Piston and Bearing

How to Select Piston and Bearing

* 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.

DESCRIPTION
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, refer to the text.

HOW TO SELECT PISTON

Piston Selective Fitting When New Cylinder Block is Used:
Check the cylinder bore grade on the rear upper side between cylinder block banks, and select the piston of the same grade.

When Cylinder Block is Reused:
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.

Piston Selection Table:

NOTE: The piston is available together with piston pin as an assembly.
The piston pin (piston pin bore) grade is provided only for the parts installed at the plant. For service parts, no grades can be selected (Only 0 grade is available.).

HOW TO SELECT CONNECTING ROD BEARING

When New Connecting Rod and Crankshaft are Used:
Compare the pin diameter grade of the crankshaft front surface with the values of the selection table of connecting rod bearing.

NOTE: There is no grading for connecting rod big end.

When Crankshaft and Connecting Rod are Reused:
1. Measure the pin outer diameter of the crankshaft.
2. Compare the measurement with the values of the selection table of connecting rod bearing.

Selection Table of Connecting Rod Bearing:

NOTE: (At shipment from the plant) For an engine, all the connecting rod assemblies are in the same weight class. For service parts, no weight grades can be selected.

Under Size Bearings Usage Guide
When the specified oil clearance is not obtained with standard size connecting rod bearings, use undersize (US) bearings.

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

Bearing undersize table:

CAUTION: In grinding the crankshaft pin to use undersize bearings, do not damage the fillet R (All crankshaft pins).

HOW TO SELECT MAIN BEARING

When New Cylinder Block and Crankshaft are Used:
1. Apply main bearing housing grade on upper rear side between cylinder block banks to row in main bearing selection table.

2. Apply journal diameter grade on crankshaft front to column in main bearing selection table.
3. Find sign at crossing of row and column in main bearing selection table.

CAUTION: Initial clearance for No.1, 5 journal and No. 2, 3, 4 journal is different. Use two different selection lists for each part.
No.1, 5 journal and No. 2, 3, 4 journal have the same signs but different measures. Do not confuse.

4. Apply sign at crossing in above step 3 to main bearing grade table.

NOTE: Grade list applies to all journals.
Service parts is available as a set of both upper and lower.

When Cylinder Block and Crankshaft are Reused:
1. Measure inner diameter of cylinder block main bearing housing and outer diameter of crankshaft journal.
2. Apply measurement in above step 1 to main bearing selection table.
3. Follow step 3 and later in "When new cylinder block and crankshaft are used".

Main Bearings Selection Table (No. 1 and No. 5 journal):

Main Bearings Selection Table (No. 2, 3 and 4 journal):

Main Bearings Grade Table (All Journals):

Use Undersize Bearing Usage Guide
Use Undersize (US) bearing when oil clearance with standard size main bearing is not within specification.

When using Undersize (US) bearing, measure inner diameter of bearing installed and grind journal until oil clearance falls within specification.

Bearing undersize table:

CAUTION: Do not damage fillet R when grinding crankshaft journal in order to use undersized bearing (All journals).