NISSAN PATROL 1998 Y61 / 5.G Engine Mechanical Repair Manual

3. Measure piston skirt diameter.
Piston diameter ``A'':
Refer to SDS, EM-61.
Measuring point ``a'' (Distance from the bottom):
18 mm (0.71 in)
4. Check that piston-to-bore clearance is within speci®cation.
Piston-to-bore clearance ``B'' = Bore measurement
``C'' þ Piston diameter ``A'':
0.025 - 0.045 mm (0.0010 - 0.0018 in)
5. Determine piston oversize according to amount of cylinder
wear.
Oversize pistons are available for service. Refer to SDS,
EM-61.
6. Cylinder bore size is determined by adding piston-to-bore clear-
ance to piston diameter ``A''.
Rebored size calculation:
D=A+BþC
where,
D: Bored diameter
A: Piston diameter as measured
B: Piston-to-bore clearance
C: Honing allowance 0.02 mm (0.0008 in)
7. Install main bearing cap and tighten bolts to 90 to 100 Nzm (9.2
to 10.2 kg-m, 67 to 74 ft-lb). This will prevent distortion of cyl-
inder bores.
8. 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 at a time.
9. Hone cylinders to obtain speci®ed piston-to-bore clearance.
10. Measure ®nished cylinder bore for out-of-round and taper.
+Measurement should be done after cylinder bore cools
down.
SEM181B
SEM755B
CYLINDER BLOCK
Inspection (Cont'd)
EM-50

CRANKSHAFT
1. Check crankshaft main and pin journals for score, wear or
cracks.
2. With a micrometer, measure journals for taper and out-of-
round.
Out-of-round (X þ Y):
Main journal
Less than 0.005 mm (0.0002 in)
Pin journal
Less than 0.0025 mm (0.0001 in)
Taper (A þ B):
Main journal
Less than 0.005 mm (0.0002 in)
Pin journal
Less than 0.0025 mm (0.0001 in)
3. Measure crankshaft runout.
Runout (Total indicator reading):
Standard Less than 0.025 mm (0.0010 in)
Limit 0.05 mm (0.0020 in)
BEARING CLEARANCE
+Use Method A or Method B. Method A is preferred because it
is more accurate.
Method A (Using bore gauge and micrometer)
Main bearing
1. Set main bearings in their proper positions on cylinder block
and main bearing cap.
2. Install main bearing cap to cylinder block.
Tighten all bolts in correct order in two or three stages. Refer
to EM-54.
3. Measure inner diameter ``A'' of each main bearing.
SEM316A
SEM906A
SEM157B
SEM753B
CYLINDER BLOCK
Inspection (Cont'd)
EM-51

4. Measure outer diameter ``Dm'' of each crankshaft main journal.
5. Calculate main bearing clearance.
Main bearing clearance = A þ Dm:
Standard 0.036 - 0.063 mm (0.0014 - 0.0025 in)
Limit 0.12 mm (0.0047 in)
If it exceeds the limit, replace bearing.
+If clearance cannot be adjusted within the standard of any
bearing, grind crankshaft journal and use undersized bearing.
+If crankshaft or cylinder block is replaced, select thickness of
main bearings as follows:
a. Grade number of each cylinder block main journal is punched
on the respective cylinder block. These numbers are punched
in either Arabic or Roman numerals.
b. Grade number of each crankshaft main journal is punched on
the respective crankshaft. These numbers are punched in
either Arabic or Roman numerals.
c. Select main bearing with suitable thickness according to the
following table.
Main bearing grade number:
Main journal grade number 0 1 2
Crankshaft
journal grade
number0012
1123
2234
For example:
Main journal grade number: 1
Crankshaft journal grade number: 2
Main bearing grade number=1+2=3
Connecting rod bearing (Big end)
1. Install connecting rod bearing to connecting rod and cap.
2. Install connecting rod cap to connecting rod.
Tighten bolts to the speci®ed torque. Refer to EM-20.
3. Measure inner diameter ``C'' of each bearing.
AEM033
SEM912A
SEM911A
AEM027
CYLINDER BLOCK
Inspection (Cont'd)
EM-52

4. Measure outer diameter ``Dp'' of each crankshaft pin journal.
5. Calculate connecting rod bearing clearance.
Connecting rod bearing clearance=CþDp:
Standard
0.014 - 0.054 mm (0.0006 - 0.0021 in)
Limit
0.090 mm (0.0035 in)
If it exceeds the limit, replace bearing.
+If it still exceeds the limit even with a new bearing, regrind crank
pin and use undersized bearings.
+Refer to SDS for regrinding crankshaft and available ser-
vice parts.
Method B (Using plastigage)
CAUTION:
+Do not turn crankshaft or connecting rod while plastigage
is being inserted.
+If incorrect bearing clearance exists, use a thicker or
undersized main bearing to ensure speci®ed clearance.
CONNECTING ROD BUSHING CLEARANCE (Small end)
1. Measure inner diameter ``C'' of bushing.
2. Measure outer diameter ``Dp'' of piston pin.
3. Calculate connecting rod bushing clearance.
Connecting rod bushing clearance=CþDp
Standard:
0.025 - 0.044 mm (0.0010 - 0.0017 in)
If it exceeds the limit, replace connecting rod assembly or con-
necting rod bushing and/or piston set with pin.
REPLACEMENT OF CONNECTING ROD BUSHING
(Small end)
1. Drive in small end bushing until it is ¯ush with end surface of
rod.
Be sure to align the oil holes.
2. Ream the bushing so that clearance with piston pin is within
speci®cation.
Clearance between connecting rod bushing and pis-
ton pin:
0.005 - 0.017 mm (0.0002 - 0.0007 in)
FLYWHEEL/DRIVE PLATE RUNOUT
Runout (Total indicator reading):
Less than 0.15 mm (0.0059 in)
CAUTION:
+Be careful not to damage the ring gear teeth.
+Check the drive plate for deformation or cracks.
+Do not allow any magnetic materials to contact the ring
gear teeth.
+Do not resurface drive plate. Replace as necessary.
AEM034
EM142
SEM673E
SEM062A
SEM929A
CYLINDER BLOCK
Inspection (Cont'd)
EM-53

Assembly
PISTON
1. Install new snap ring on one side of piston pin hole.
2. Heat piston to 60 to 70ÉC (140 to 158ÉF) and assemble piston,
piston pin, connecting rod and new snap ring.
+Align the direction of piston and connecting rod.
+Numbers stamped on connecting rod and cap correspond
to each cylinder.
+After assembly, make sure connecting rod swings
smoothly.
3. Set piston rings as shown.
CAUTION:
+When piston rings are not replaced, make sure that piston
rings are mounted in their original positions.
+Install new piston rings either side up if there is no punch-
mark.
+Align piston rings so that end gaps are positioned as
shown.
CRANKSHAFT
1. Set main bearings in their proper positions on cylinder block
and main bearing cap.
+Con®rm that correct main bearings are selected by using
Method A or Method B. Refer to EM-52.
+Apply new engine oil to bearing surfaces.
SEM146B
SEM754B
SEM156B
SEM160B
SEM157B
CYLINDER BLOCK
EM-54

2. Install crankshaft and main bearing caps and tighten bolts to
the speci®ed torque.
+Apply new engine oil to the bolt thread and seat surface.
+Prior to tightening bearing cap bolts, shift crankshaft back
and forth to properly seat the bearing cap.
+Tighten bearing cap bolts gradually in two or three steps.
Start with center bearing and move outward as shown in
®gure.
+After securing bearing cap bolts, make sure crankshaft
turns smoothly by hand.
3. Measure crankshaft end play.
Crankshaft end play:
Standard
0.050 - 0.18 mm (0.0020 - 0.0071 in)
Limit
0.30 mm (0.0118 in)
If beyond the limit, replace thrust bearing with a new one.
4. Install connecting rod bearings in connecting rods and connect-
ing rod caps.
+Con®rm that correct bearings are selected. Refer to ``Con-
necting rod bearing (Big end)'', EM-52.
+Install bearings so that oil hole in connecting rod aligns
with oil hole of bearing.
+Apply new engine oil to bearing surfaces, bolt threads and
seating surfaces.
5. Install pistons with connecting rods.
a. Install them into corresponding cylinders with Tool.
+Make sure connecting rod does not scratch cylinder wall.
+Make sure connecting rod bolts do not scratch crankshaft
pin journals.
+Arrange so that front mark on piston head faces toward
front of engine.
+Apply new engine oil to piston rings and sliding surface of
piston.
b. Install connecting rod caps.
+Apply new engine oil to bolt threads and nut seating sur-
faces.
Tighten connecting rod cap nuts using the following procedure.
(1) Tighten to 14 to 16 Nzm
(1.4 to 1.6 kg-m, 10 to 12 ft-lb).
(2) Turn nuts 60 to 65É clockwise with an angle wrench. If
an angle wrench is not available, tighten nuts to 37 to
45 Nzm (3.8 to 4.6 kg-m, 27 to 33 ft-lb).
SEM801FA
SEM756B
SEM757B
SEM936A
SEM759B
CYLINDER BLOCK
Assembly (Cont'd)
EM-55

6. Measure connecting rod side clearance.
Connecting rod side clearance:
Standard
0.20 - 0.30 mm (0.0079 - 0.0118 in)
Limit
0.40 mm (0.0157 in)
If beyond the limit, replace connecting rod and/or crankshaft.
SEM760B
CYLINDER BLOCK
Assembly (Cont'd)
EM-56

General Speci®cations
Cylinder arrangement In-line 6
Displacement cm
3(cu in) 2,826 (172.44)
Bore and stroke mm (in) 85 x 83 (3.35 x 3.27)
Valve arrangement OHC
Firing order 1-5-3-6-2-4
Number of piston rings
Compression 2
Oil 1
Number of main bearings 7
Compression ratio 21.8
VALVE TIMING
Without warm-up three way catalyst
EM120Unit: degree
abcde f
248 220 7 33 8 60
Inspection and Adjustment
COMPRESSION PRESSURE
Unit: kPa (bar, kg/cm2, psi)/200 rpm
Compression pressure
Standard 3,040 (30.4, 31, 441)
Minimum 2,452 (24.5, 25, 356)
Differential limit between
cylinders490 (4.9, 5, 71)
CYLINDER HEAD
Unit: mm (in)
Standard Limit
Head surface distortionLess than
0.03 (0.0012)0.1 (0.004)
SEM795F
Nominal cylinder head height ``H''139.9 - 140.1
(5.508 - 5.516)
Resurfacing limit 0.1 (0.004)
SERVICE DATA AND SPECIFICATIONS (SDS)
EM-57

VA LV E
Unit: mm (in)
SEM188A
Valve head diameter ``D''
Intake 39.0 - 39.3 (1.535 - 1.547)
Exhaust 32.0 - 32.3 (1.260 - 1.272)
Valve length ``L''
Intake101.53 - 101.97
(3.9972 - 4.0146)
Exhaust101.38 - 101.82
(3.9913 - 4.0087)
Valve stem diameter ``d''
Intake 6.965 - 6.980 (0.2742 - 0.2748)
Exhaust 6.945 - 6.960 (0.2734 - 0.2740)
Valve seat angle ``a''
Intake
45É15¢- 45É45¢
Exhaust
Valve margin ``T''
Intake 1.35 - 1.65 (0.0531 - 0.0650)
Exhaust 1.65 - 1.95 (0.0650 - 0.0768)
Valve margin ``T'' limit More than 0.5 (0.020)
Valve stem end surface
grinding limitLess than 0.2 (0.008)
Valve lifter
Unit: mm (in)
Valve lifter diameter34.960 - 34.975
(1.3764 - 1.3770)
Lifter guide hole diameter34.998 - 35.018
(1.3779 - 1.3787)
Clearance between lifter and lifter guide hole0.023 - 0.058
(0.0009 - 0.0023)
Valve guide
Unit: mm (in)
SEM796F
Standard Service
Valve guide
Outer
diameterIntake11.023 - 11.034
(0.4340 - 0.4344)11.233 - 11.234
(0.4422 - 0.4423)
Exhaust11.023 - 11.034
(0.4340 - 0.4344)11.233 - 11.234
(0.4422 - 0.4423)
Valve guide
Inner diam-
eter (Fin-
ished size)Intake 7.000 - 7.018 (0.2756 - 0.2763)
Exhaust 7.000 - 7.018 (0.2756 - 0.2763)
Cylinder head
valve guide
hole diameterIntake10.975 - 10.996
(0.4321 - 0.4329)11.185 - 11.196
(0.4404 - 0.4408)
Exhaust10.975 - 10.996
(0.4321 - 0.4329)11.185 - 11.196
(0.4404 - 0.4408)
Interference ®t of valve
guide0.027 - 0.059 (0.0011 - 0.0023)
Standard Limit
Stem to guide
clearanceIntake0.020 - 0.050
(0.0008 - 0.0020)0.1 (0.004)
Exhaust0.040 - 0.070
(0.0016 - 0.0028)0.1 (0.004)
Valve de¯ection limit 0.2 (0.008)
Projection length ``L'' 10.2 - 10.4 (0.402 - 0.409)
SERVICE DATA AND SPECIFICATIONS (SDS)
Inspection and Adjustment (Cont'd)
EM-58

Valve seat
Unit: mm (in)
SEM788BASEM773BA
SEM790BASEM789BA
Cylinder head to valve distance
Unit: mm (in)
SEM724C
Standard
Intakeþ0.069 to 0.269
(þ0.0027 to 0.0106)
Exhaustþ0.069 to 0.269
(þ0.0027 to 0.0106)
Valve spring
Free height mm (in)
Outer 42.25 (1.6634)
Inner 36.57 (1.4398)
Pressure height/Load
mm/N (mm/kg, in/lb)
Outer25.7/437.69 (25.7/44.63,
1.012/98.41)
Inner22.2/233.21 (22.2/23.78,
0.874/52.43)
Out-of-square mm (in)
Outer 1.9 (0.075)
Inner 1.6 (0.063)
SERVICE DATA AND SPECIFICATIONS (SDS)
Inspection and Adjustment (Cont'd)
EM-59