1998 NISSAN PATROL Piston

VALVE LIFTER
1. Check contact and sliding surfaces for wear or scratches.
2. Check diameter of a valve lifter.
Outer diameter:
34.960 - 34.975 mm (1.3764 - 1.3770 in)
3. Check valve lifter guide bore.
Bore diameter:
34.998 - 35.018 mm (1.3779 - 1.3787 in)
Standard clearance:
0.023 - 0.058 mm (0.0009 - 0.0023 in)
If valve lifters are noisy, check valve lifter.
(1) Depress plunger forcibly with your ®nger.
If it moves about 1 mm (0.04 in), it indicates air is inside valve lifter.
(2) Reinstall valve lifter.
(3) Bleed air by running engine at 2,400 rpm under no-load for
about 20 minutes.
CAUTION:
When camshaft is removed to install, remove or inspect
hydraulic valve lifters, do not start engine for at least 30 min-
utes after reinstalling camshaft. (Wait until hydraulic valve lift-
ers have reached their set lengths.) Before starting engine,
rotate crankshaft by hand to ensure pistons do not interfere
with valves.
(4) Next check to ensure all air is bled. [Refer to step (1) above.]
(5) If there is still air, replace valve lifter.
SEM723B
SEM724B
SEM725B
CYLINDER HEAD
Inspection (Cont'd)
EM-36

Assembly
1. Install valve component parts.
Install valve spring with its narrow pitch side toward cylinder
head side.
a. When installing valve, apply engine oil on the valve stem
and lip of valve oil seal.
b. Check whether the valve face is free from foreign matter.
c. Install valve spring retainers on the intake side and valve
rotators on the exhaust side.
d. Valve rotators cannot be disassembled.
2. Set camshaft.
Set camshaft so that dowel pin faces up.
3. Install cam bracket caps so that front mark faces forward.
Cam bracket nut (Tighten in two or three stages):
:21-26Nzm
(2.1 - 2.7 kg-m, 15 - 20 ft-lb)
4. Apply engine oil to new oil seal and install it.
Installation
1. Install cylinder head gasket.
a. When replacing only cylinder head gasket, install same
grade gasket as the one formerly used.
b. When replacing or repairing cylinder block, cylinder head,
piston, connecting rod and crankshaft, select gasket as
follows:
SEM202
SEM731BB
SEM732B
SEM733B
CYLINDER HEAD
EM-38

Step 1:
Measure piston projection.
1) Set dial gauge on cylinder block surface to zero.
2) Set dial gauge at measuring point of piston, being careful not
to disturb its zero setting.
3) Set each piston at its Top Dead Center. With piston held in that
position, measure its projections at four points, M1, M2, M3 and
M4, and record measured values.
Be sure to measure the projection at four points for every cyl-
inder as shown.
Step 2:
Calculate the average value of measured projections for each cyl-
inder.
Step 3:
Calculate the average value of projections for all pistons.
Step 4:
Round off the average value.
Step 5:
Determine the gasket thickness, referring to chart A.
Relation between piston projection and cylinder head gasket
(Chart A)
Unit: mm (in)
GradeAverage values
piston projectionsGasket thicknessNumber of
identi®cations
ALess than
0.79 (0.0311)1.42 0.05
(0.0559 0.0020)1
B0.79 - 0.875
(0.0311 - 0.0344)1.50 0.05
(0.0591 0.0020)2
CMore than
0.875 (0.0344)1.58 0.05
(0.0622 0.0020)3
Step 6:
Check to see if the average value of each projection in step 2 is
larger than the max. value of the standard projection (of selected
gasket) plus 0.08 mm (0.0031 in).
Step 7:
If it is, use gasket that is 1 grade thicker.
If it is not, use gasket that was selected in step 4.
SEM734B
SEM735B
SEM736B
CYLINDER HEAD
Installation (Cont'd)
EM-39

CAUTION:
+When installing sliding parts such as bearings and
pistons, apply engine oil to the sliding surfaces.
+Place removed parts, such as bearings and bearing caps,
in their proper order and direction.
+When installing connecting rod bolts and main bearing cap
bolts, apply new engine oil to threads and seating surfaces
of nuts.
+Do not allow any magnetic materials to contact the ring
gear teeth of drive plate.
Disassembly
PISTON AND CRANKSHAFT
1. Place engine on a work stand.
2. Remove timing belt and injection pump.
3. Drain coolant and remove water pump.
4. Remove front cover.
5. Drain oil.
6. Remove oil pan and oil pump.
7. Remove cylinder head.
8. Remove pistons with connecting rod.
+To disassemble piston and connecting rod, remove snap ring
®rst. Then heat piston to 60 to 70ÉC (140 to 158ÉF) and use
piston pin press to remove pin.
+When piston rings are not replaced, make sure that piston
rings are mounted in their original positions.
+When replacing piston rings, if there is no punchmark,
install with either side up.
9. Remove bearing cap bolts and main bearing caps in the order
shown, then remove crankshaft.
+Loosen bolts in two or three steps.
Inspection
PISTON AND PISTON PIN CLEARANCE
1. Measure inner diameter of piston pin hole ``dp''.
Standard diameter ``dp'':
26.995 - 27.005 mm (1.0628 - 1.0632 in)
SEM750B
SEM877B
SEM801F
SEM672E
CYLINDER BLOCK
EM-47

2. Measure outer diameter of piston pin ``Dp''.
Standard diameter ``Dp'':
26.994 - 27.000 mm (1.0628 - 1.0630 in)
3. Calculate piston pin clearance.
dp þ Dp = þ0.004 to 0 mm (þ0.0002 to 0 in)
If it exceeds the above value, replace piston assembly with pin.
PISTON RING SIDE CLEARANCE
Side clearance:
Top ring
0.060 - 0.093 mm (0.0024 - 0.0037 in)
2nd ring
0.040 - 0.073 mm (0.0016 - 0.0029 in)
Max. limit of side clearance:
0.1 mm (0.004 in)
If out of speci®cation, replace piston ring. If clearance exceeds
maximum limit with new ring, replace piston.
PISTON RING END GAP
End gap:
Top ring
0.20 - 0.28 mm (0.0079 - 0.0110 in)
2nd ring
0.20 - 0.46 mm (0.0079 - 0.0181 in)
Oil ring
0.30 - 0.56 mm (0.0118 - 0.0220 in)
Max. limit of ring gap:
0.4 mm (0.016 in)
If out of speci®cation, replace piston ring. If gap still exceeds maxi-
mum limit with new ring, rebore cylinder and use oversized piston
and piston rings. Refer to SDS, EM-62.
+When replacing the piston, check cylinder block surface
for scratches or seizure. If scratches or seizure are found,
hone or replace the cylinder block.
CONNECTING ROD BEND AND TORSION
Bend:
Limit 0.025 mm (0.0010 in)
per 100 mm (3.94 in) length
Torsion:
Limit 0.025 mm (0.0010 in)
per 100 mm (3.94 in) length
If it exceeds the limit, replace connecting rod assembly.
SEM024AA
SEM822B
SEM038F
CYLINDER BLOCK
Inspection (Cont'd)
EM-48

CYLINDER BLOCK DISTORTION AND WEAR
1. Clean upper surface of cylinder block. Using a reliable straight-
edge and feeler gauge, check the ¯atness of cylinder block
surface.
+Check along six positions as shown in ®gure.
Limit:
0.10 mm (0.0039 in)
2. If out of speci®cation, resurface it.
The limit for cylinder block resurfacing is determined by the
amount of cylinder head resurfacing.
Amount of cylinder head resurfacing is ``A''.
Amount of cylinder block resurfacing is ``B''.
The maximum limit is as follows:
A + B = 0.2 mm (0.008 in)
Nominal cylinder block height
from crankshaft center:
227.40 - 227.50 mm (8.9527 - 8.9567 in)
3. If necessary, replace cylinder block.
PISTON-TO-BORE CLEARANCE
1. Using a bore gauge, measure cylinder bore for wear, out-of-
round and taper.
Standard inner diameter ``Db'':
85.000 - 85.030 mm (3.3465 - 3.3476 in)
Wear limit:
0.20 mm (0.0079 in)
Out-of-round (X þ Y):
Less than 0.015 mm (0.0006 in)
Taper (A þ B or A þ C):
Less than 0.010 mm (0.0004 in)
If it exceeds the limit, rebore all cylinders. Replace cylinder block if
necessary.
2. Check for scratches and seizure. If seizure is found, hone it.
SEM907A
SEM908A
SEM909A
CYLINDER BLOCK
Inspection (Cont'd)
EM-49

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

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