Nissan Xterra. Manual - part 372

EM-116

< UNIT DISASSEMBLY AND ASSEMBLY >

[VQ40DE]

ENGINE UNIT

Measure diameter of piston pin using suitable tool.

Connecting Rod Bushing Oil Clearance (Small End)

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

ter)

• If the calculated value exceeds the limit, replace connecting rod assembly and/or piston and piston pin

assembly.

• If replacing piston and piston pin assembly. Refer to 

EM-125, "How to Select Piston and Bearing"

.

• If replacing connecting rod assembly, follow the "CONNECTING

ROD BEARING OIL CLEARANCE" procedure to select the con-

necting rod bearing.

Factory installed parts grading:

• Only grade “0”.

Unit: mm (in)

*: After installing in connecting rod

CYLINDER BLOCK DISTORTION

• Remove any oil, scale, gasket, sealant and carbon deposits from the cylinder block surface. 

CAUTION:

Do not allow any debris to enter engine oil or engine coolant passages.

Standard

: 21.989 - 22.001 mm (0.8657 - 0.8662 in)

PBIC0117E

Standard

: 0.005 - 0.017 mm (0.0002 - 0.0007 in)

Limit

: 0.030 mm (0.0012 in)

PBIC0809E

               Grade

                    0

                    1

Connecting rod bushing 
inner diameter *

         22.000 - 22.006          
       (0.8661 - 0.8664)

         22.006 - 22.012
        (0.8664 - 0.8666)

Piston pin hole diameter

        21.993 - 21.999
       (0.8659 - 0.8661)

         21.999 - 22. 005
        (0.8661 - 0.8663)

Piston pin outer diameter

        21.989 - 21.995
       (0.8657- 0.8659)

         21.995 - 22.001
        (0.8659 - 0.8662)

PBIC2950E

ENGINE UNIT

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• Measure the distortion on the cylinder block upper face at some

different points in six directions with straightedge and feeler gauge.

• If it exceeds the limit, replace cylinder block.

MAIN BEARING HOUSING INNER DIAMETER

• Install lower cylinder block without installing main bearings, and

tighten lower cylinder block bolts to the specified torque. Refer to

EM-103, "Disassembly and Assembly"

 for the tightening proce-

dure.

• Measure the inner diameter of main bearing housing with bore

gauge.

• If out of the standard, replace cylinder block and lower cylinder

block as assembly.

NOTE:

Cylinder block cannot be replaced as a single part, because it is

machined together with lower cylinder block.

PISTON TO CYLINDER BORE CLEARANCE

Cylinder Bore Inner Diameter

• Using bore gauge, measure cylinder bore for wear, out-of-round

and taper at six different points on each cylinder. [(X) and (Y) direc-

tions at (A), (B) and (C)] [(X) is in longitudinal direction of engine].

• If the measured value exceeds the limit, or if there are scratches

and/or seizure on the cylinder inner wall, hone or re-bore the inner

wall.

Piston Skirt Diameter

Limit : 0.1 mm (0.004 in)

SEM123C

Standard

: 74.993 - 75.017 mm (2.9525 - 2.9534 in)

PBIC2012E

Standard inner diameter:

95.500 - 95.530 mm (3.7598 - 3.7610 in)

Out-of-round [Difference between (X) and (Y)]:

0.015 mm (0.0006 in)

Taper limit [Difference between (A) and (C)]:
  0.01 mm (0.0004 in)

PBIC2955E

SEM843E

EM-118

< UNIT DISASSEMBLY AND ASSEMBLY >

[VQ40DE]

ENGINE UNIT

Measure the outer diameter of piston skirt with micrometer.

Piston to Cylinder Bore Clearance

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

(Clearance) = (Cylinder bore inner diameter) – (Piston skirt diameter).

• If the calculated value exceeds the limit, replace piston and piston pin assembly. Refer to 

EM-125, "How to

Select Piston and Bearing"

.

Re-boring Cylinder Bore

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

2. Install lower cylinder block, and tighten to the specified torque. Otherwise, cylinder bores may be distorted

in final assembly.

3. Cut cylinder bores.

NOTE:

• 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 the specified piston to cylinder bore clearance.
5. Measure finished the cylinder bore for out-of-round and taper.

NOTE:

Measurement should be done after cylinder bore cools down.

CRANKSHAFT MAIN JOURNAL DIAMETER

• Measure the outer diameter of crankshaft main journals with micrometer.

• If out of the standard, measure the main bearing oil clearance. Then use undersize bearing.

CRANKSHAFT PIN JOURNAL DIAMETER

Measure point

: Distance from the top 43.03 mm (1.6941 in)

Standard

: 95.480 - 95.510 mm (3.7590 - 3.7602 in)

PBIC2956E

Standard

: 0.010 - 0.030 mm (0.0004 - 0.0012 in)

Limit

: 0.08 mm (0.0031 in)

Re-bored size calculation: D = A + B – C
where,

D: Bored diameter
A: Piston skirt diameter as measured
B: Piston to cylinder bore clearance (standard value)
C: Honing allowance 0.02 mm (0.0008 in)

Standard

: 69.951 - 69.975 mm (2.7540 - 2.7549 in) dia.

ENGINE UNIT

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• Measure the outer diameter of crankshaft pin journal with

micrometer.

• If out of the standard, measure the connecting rod bearing oil

clearance. Then use undersize 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 micrometer. 

• Out-of-round is indicated by the difference in the dimensions

between (X) and (Y) at (A) and (B).

• Taper is indicated by the difference in the dimensions between (A)

and (B) at (X) and (Y).

• If the measured value exceeds the limit, correct or replace crankshaft.

• If corrected, measure the bearing oil clearance of the corrected main journal and/or pin journal. Then select

the main bearing and/or connecting rod bearing.

CRANKSHAFT RUNOUT

• Place V-block on precise flat table, and support the journals on

both ends of crankshaft.

• Place dial indicator straight up on the No. 3 journal.

• While rotating crankshaft, read the movement of the pointer on dial

indicator. (Total indicator reading)

• If it exceeds the limit, replace crankshaft.

CONNECTING ROD BEARING OIL CLEARANCE

Method by Calculation

• Install connecting rod bearings to connecting rod and cap, and

tighten connecting rod bolts to the specified torque. Refer to 

EM-

103, "Disassembly and Assembly"

 for the tightening procedure.

• Measure the inner diameter of connecting rod bearing with inside

micrometer.

(Bearing oil clearance) = (Connecting rod bearing inner diameter) –

(Crankshaft pin journal diameter)

• If the calculated value exceeds the limit, select proper connecting rod bearing according to connecting rod

big end diameter and crankshaft pin journal diameter to obtain the specified bearing oil clearance. Refer to

EM-125, "How to Select Piston and Bearing"

.

Standard

: 53.956 - 53.974 mm (2.1242 - 2.1250 in) dia.

PBIC0127E

Limit:

Out-of-round [Difference between (X) and (Y)]

: 0.002 mm (0.0001 in)

Taper [Difference between (A) and (B)]

: 0.002 mm (0.0001 in)

SBIA0535E

Standard : Less than 0.05 mm (0.002 in)
Limit

: 0.10 mm (0.0039 in)

SEM346D

Standard

: 0.034 - 0.059 mm (0.0013 - 0.0023 in) (actu-

al clearance)

Limit

: 0.070 mm (0.0028 in)

PBIC1642E