Cylinder Block: Inspection

WARNING: This page is about a different car, the 2023 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.

CRANKSHAFT END PLAY

Measure the clearance between thrust bearings and crankshaft arm when crankshaft is moved fully forward or backward with a suitable tool (A).

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Standard and Limit : Refer to Cylinder Block .

If the measured value exceeds the limit, replace thrust bearings, and measure again.
If it still exceeds the limit, replace crankshaft also.

CONNECTING ROD SIDE CLEARANCE

Measure the side clearance between connecting rod and crankshaft arm with a suitable tool (A).

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Standard and Limit : Refer to Cylinder Block .
If the measured value exceeds the limit, replace connecting rod, and measure again. If it still exceeds the limit, replace crankshaft also.

PISTON TO PISTON PIN OIL CLEARANCE

Piston Pin Hole Diameter

Measure the inner diameter of piston pin hole with a suitable tool (A).

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Standard

: Refer to Cylinder Block .

Piston Pin Outer Diameter

Measure the outer diameter of piston pin with a suitable tool (A).

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Standard

: Refer to Cylinder Block .

Piston to Piston Pin Oil Clearance

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

Standard

: Refer to Cylinder Block .

If oil clearance is out of the standard, replace piston and piston pin assembly.
NOTE:
- Piston is available together with piston pin as assembly.
- Piston pin (piston pin hole) grade is provided only for the parts installed at the plant. For service parts, no grades can be selected. (Only grade "0" is available.)

PISTON RING SIDE CLEARANCE

Measure the side clearance of piston ring and piston ring groove with a suitable tool (A).

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Standard and Limit

: Refer to Cylinder Block .

If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit, replace piston also.

PISTON RING END GAP

Check that cylinder bore inner diameter is within specification. Refer to "PISTON TO CYLINDER BORE CLEARANCE".
Lubricate with new engine oil to piston (1) and piston ring (2), and then insert (A) piston ring until middle of cylinder (B) with piston, and measure piston ring end gap with a suitable tool (C).

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Standard and Limit : Refer to Cylinder Block .
If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit, rebore cylinder and use oversized piston and piston rings.

CONNECTING ROD BEND AND TORSION

Check with a suitable tool (C).

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(A) : Bend

(B) : Torsion

Limit : Refer to Cylinder Block .
If it exceeds the limit, replace connecting rod assembly.

CONNECTING ROD BIG END DIAMETER

Install connecting rod cap (1) without connecting rod bearing installed, and tightening connecting rod cap bolts to the specified torque. Refer to Disassembly and Assembly .

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Measure the inner diameter of connecting rod big end with an inside micrometer.

Standard : Refer to Cylinder Block .

(2) : Connecting rod
If out of the standard, replace connecting rod assembly.

CONNECTING ROD BUSHING OIL CLEARANCE

Connecting Rod Bushing Inner Diameter

Measure the inner diameter of connecting rod bushing with a suitable tool (A).

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Standard

: Refer to Cylinder Block .

Piston Pin Outer Diameter

Measure the outer diameter of piston pin with a suitable tool (A).

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Standard

: Refer to Cylinder Block .

Connecting Rod Bushing Oil Clearance

(Connecting rod bushing oil clearance) = (Connecting rod bushing inner diameter) - (Piston pin outer diameter)

Standard and Limit

: Refer to Cylinder Block .

If the measured value is out of the standard, replace connecting rod assembly and/or piston and piston pin assembly.
If replacing piston pin assembly, refer to Piston .
If replacing connecting rod assembly, refer to Connecting Rod Bearing .

CYLINDER BLOCK TOP SURFACE DISTORTION

Using a suitable tool, remove gasket on the cylinder block surface, and also remove engine oil, scale, carbon, or other contamination.
CAUTION:
Be careful not to allow gasket particles to enter engine oil or engine coolant passages.
Measure the distortion on the cylinder block upper face at different points in six different directions with a suitable tool (A) and suitable tool (B).

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Limit : Refer to Cylinder Block .
If it exceeds the limit, replace cylinder block.

MAIN BEARING HOUSING INNER DIAMETER

Install main bearing cap without main bearings installed, and tighten main bearing cap mounting bolts to the specified torque. Refer to Disassembly and Assembly .
Measure the inner diameter of main bearing housing with a suitable tool.

Measure the position shown backward from main bearing housing front side in the 2 directions as shown. The smaller one is the measured value.

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Standard

: Refer to Cylinder Block .

(1)	: Cylinder block
(2)	: Main bearing cap
(B)	: 5 mm (0.20 in)
(C)	: 15°
	: Engine front

If out of the standard, replace cylinder block and main bearing caps assembly.
NOTE: Main bearing caps cannot be replaced as a single, because it is machined together with cylinder block.

PISTON TO CYLINDER BORE CLEARANCE

Cylinder Bore Inner Diameter

Using a cylinder gauge, measure the cylinder bore for wear, out-of-round and taper at six different points on each cylinder. [ (A) and (B) directions at (C), (D), and (E) ] [ (A) is in longitudinal direction of engine]

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NOTE:

When determining cylinder bore grade, measure the cylinder bore (B) direction at (D) position.

(F)	: 10 mm (0.39 in)
(G)	: 60 mm (2.36 in)
(H)	: 130 mm (5.12 in)

Standard:
Cylinder bore inner diameter	: Refer to Cylinder Block .

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

If the measured value exceeds the limit, or if there are scratches and/or seizure on the cylinder inner wall, replace cylinder block.
NOTE: Oversize piston is not provided.

Piston Skirt Diameter

Measure the outer diameter of piston skirt with a suitable tool (A).

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Standard

: Refer to Cylinder Block .

Piston to Cylinder Bore Clearance

Calculate by piston skirt diameter and cylinder bore inner diameter [direction (B), position (D) ].

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(A)	: Direction A
(C)	: Position C
(E)	: Position E
(F)	: 10 mm (0.39 in)
(G)	: 60 mm (2.36 in)
(H)	: 130 mm (5.12 in)

(Clearance) = (Cylinder bore inner diameter) - (Piston skirt diameter)

Standard and Limit

: Refer to Cylinder Block .

If it exceeds the limit, replace piston and piston pin assembly and/or cylinder block. Refer to Piston .

CRANKSHAFT MAIN JOURNAL DIAMETER

Measure the outer diameter of crankshaft main journals with a suitable tool (A).

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Standard : Refer to Cylinder Block .
If out of the standard, measure the main bearing oil clearance. Then use undersize bearing. Refer to Main Bearing .

CRANKSHAFT PIN JOURNAL DIAMETER

Measure the outer diameter of crankshaft pin journal with a suitable tool.

Standard : Refer to Cylinder Block .
If out of the standard, measure the connecting rod bearing oil clearance. Then use undersize bearing. Refer to Connecting Rod Bearing .

OUT-OF-ROUND AND TAPER OF CRANKSHAFT

Measure the dimensions at four different points as shown on each main journal and pin journal with a suitable tool.

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Out-of-round is indicated by the difference in dimensions between (X) and (Y) at (A) and (B).

Taper is indicated by the difference in dimension between (A) and (B) at (X) and (Y).

Limit:
Out-of-round [Difference between (X) and (Y) ]
Taper [Difference between (A) and (B) ]	: Refer to Cylinder Block .

If the measured value exceeds the limit, correct or replace crankshaft.
If corrected, measure main bearing oil clearance of the corrected main journal and/or pin journal. Then select main bearing and/or connecting rod bearing. Refer to Connecting Rod Bearing and/or Main Bearing .

CRANKSHAFT RUNOUT

Place a V-block on a precise flat table to support the journals on the both end of the crankshaft.
Place a suitable tool (A) straight up on the No. 3 journal.

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While rotating crankshaft, read the movement of the pointer on the suitable tool. (Total indicator reading)

Standard and Limit : Refer to Cylinder Block .
If it exceeds the limit, replace crankshaft.

CONNECTING ROD BEARING OIL CLEARANCE

Method by Calculation

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

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Measure the inner diameter (A) of connecting rod bearing with a suitable tool. (Bearing oil clearance) = (Connecting rod bearing inner diameter) - (Crankshaft pin journal diameter)

Standard and Limit : Refer to Connecting Rod Bearing .
If clearance exceeds the limit, select proper connecting rod bearing according to connecting rod big end diameter and crankshaft pin journal diameter to obtain specified bearing oil clearance. Refer to Connecting Rod Bearing .

Method of Using Plastigage

Remove engine oil and dust on crankshaft pin and the surfaces of each bearing completely.
Cut a plastigage slightly shorter than the bearing width, and place it in crankshaft axial direction, avoiding oil holes.
Install connecting rod bearings to connecting rod and connecting rod cap, and tighten connecting rod cap bolts to the specified torque. Refer to Disassembly and Assembly .
CAUTION:
Do not rotate crankshaft.
Remove connecting rod cap and connecting rod bearing, and using the scale (A) on the plastigage bag, measure the plastigage width.

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NOTE: The procedure when the measured value exceeds the limit is same as that described in the "Method by Calculation".

MAIN BEARING OIL CLEARANCE

Method by Calculation

Install main bearings (3) to cylinder block (1) and main bearing cap (2) and tighten main bearing cap bolts to the specified torque. Refer to Disassembly and Assembly .

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Measure the inner diameter (A) of main bearing with a suitable tool.

(Bearing oil clearance) = (Main bearing inner diameter) - (Crankshaft main journal diameter)

Standard and Limit

: Refer to Main Bearing .

If clearance exceeds the limit, select proper main bearing according to main bearing inner diameter and crankshaft main journal diameter to obtain specified bearing oil clearance. Refer to Main Bearing .

Method of Using Plastigage

Remove engine oil and dust on crankshaft main journal and the surfaces of each bearing completely.
Cut a plastigage slightly shorter than the bearing width, and place it in crankshaft axial direction, avoiding oil holes.
Install main bearings to cylinder block and main bearing cap, and tighten main bearing cap bolts to the specified torque. Refer to Disassembly and Assembly .
CAUTION:
Never rotate crankshaft.
Remove main bearing cap and main bearings, and using the scale (A) on the plastigage bag, measure the plastigage width.

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NOTE: The procedure when the measured value exceeds the limit is same as that described in the "Method by Calculation".

MAIN BEARING CRUSH HEIGHT

When main bearing cap is removed after being tightened to the specified torque with main bearings (1) installed, the tip end of main bearing must protrude (B). Refer to Disassembly and Assembly .

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Standard : There must be crush height.
If the standard is not met, replace main bearings.

CONNECTING ROD BEARING CRUSH HEIGHT

When connecting rod cap is removed after being tightened to the specified torque with connecting rod bearings (1) installed, the tip end of connecting rod bearing must protrude (A). Refer to Disassembly and Assembly .

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Standard : There must be crush height.
If the standard is not met, replace connecting rod bearings.

MAIN BEARING CAP BOLT OUTER DIAMETER

Measure the outer diameters (C) and (D) at two positions as shown.

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(A)	: 30 mm (1.18 in)
(B)	: Diameter (C) measurement range 30 mm (1.18 in)
(E)	: 10 mm (0.39 in)

If reduction appears in places other than (B) range, regard it as (C).

Limit [ (D) - (C) ] : 0.15 mm (0.0059 in)
If it exceeds the limit, replace main bearing cap bolt with a new one.

CONNECTING ROD CAP BOLT OUTER DIAMETER

Measure the outer diameter (B) at position as shown.

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If reduction appears in a position other than (B), regard it as (B).

Limit : 7.75 mm (0.3051 in)

(A) : 17 mm (0.67 in)
When (B) exceeds the limit, replace connecting rod cap bolt with a new one.

(A)	: Bend
(B)	: Torsion