1999 NISSAN PICK-UP Repair Manual

2. If it exceeds the limit, check valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diam-
eter.
b. Check that clearance is within specification.
Valve to valve guide clearance = Valve guide inner diameter
þ Valve stem diameter:
Unit: mm (in)
Standard Limit
Intake0.020 - 0.053
(0.0008 - 0.0021)0.08 (0.0031)
Exhaust0.040 - 0.073
(0.0016 - 0.0029)0.1 (0.004)
c. If it exceeds the limit, replace valve and remeasure clear-
ance.
lIf clearance still exceeds the limit after replacing valve,
replace the valve guide.
VALVE GUIDE REPLACEMENT
1. To remove valve guide, heat cylinder head to 120 to 140ÉC
(248 to 284ÉF) by soaking in heated oil.
2. Drive out valve guide with a press [under a 20 kN (2 ton, 2.2
US ton, 2.0 Imp ton) pressure] or hammer and suitable tool.
3. Ream cylinder head valve guide hole.
Valve guide hole diameter
(for service parts):
Intake & Exhaust
11.175 - 11.196 mm (0.4400 - 0.4408 in)
SEM298D
SEM008A
SEM299D
SEM300D
CYLINDER HEADKA24DE
Inspection (Cont'd)
EM-2029

4. Heat cylinder head to 120 to 140ÉC (248 to 284ÉF) and press
service valve guide onto cylinder head.
Projection ªLº:
13.3 - 13.9 mm (0.524 - 0.547 in)
5. Ream valve guide.
Finished size:
Intake & Exhaust
7.000 - 7.018 mm (0.2756 - 0.2763 in)
VALVE SEATS
Check valve seats for pitting at contact surface. Resurface or
replace if excessively worn.
lBefore repairing valve seats, check valve and valve
guide for wear. If they have worn, replace them. Then
correct valve seat.
lUse both hands to cut uniformly.
REPLACING VALVE SEAT FOR SERVICE PARTS
1. Bore out old seat until it collapses. Boring should not con-
tinue beyond the bottom face of the seat recess in cylinder
head. Set the machine depth stop to ensure this.
2. Ream cylinder head recess.
Reaming bore for service valve seat
Oversize [0.5 mm (0.020 in)]:
Intake 38.000 - 38.016 mm (1.4961 - 1.4967 in)
Exhaust 32.700 - 32.716 mm (1.2874 - 1.2880 in)
Use the valve guide center for reaming to ensure valve seat
will have the correct fit.
3. Heat cylinder head to 120 to 140ÉC (248 to 284ÉF).
4. Press fit valve seat until it seats on the bottom.
SEM301D
SEM300D
SEM302D
SEM795A
SEM008A
CYLINDER HEADKA24DE
Inspection (Cont'd)
EM-2030

5. Cut or grind valve seat using suitable tool to the specified
dimensions as shown in SDS.
6. After cutting, lap valve seat with abrasive compound.
7. Check valve seating condition.
Seat face angle ªaº:
45É15¢- 45É45¢deg.
Contacting width ªWº:
Intake
1.48 - 1.63 mm (0.0583 - 0.0642 in)
Exhaust
1.8 - 2.0 mm (0.071 - 0.079 in)
8. Use a depth gauge to measure the distance between the
mounting surface of the cylinder head spring seat and the
valve stem end. If the distance is shorter than specified,
repeat step 5 above to adjust it. If it is longer, replace the
valve seat with a new one.
Valve seat resurface limit ªLº:
Intake 42.02 - 42.52 mm (1.6543 - 1.6740 in)
Exhaust 42.03 - 42.53 mm (1.6547 - 1.6744 in)
VALVE DIMENSIONS
Check dimensions of each valve. For dimensions, refer to SDS
(EM-2049).
When valve head has been worn down to 0.5 mm (0.020 in) in
margin thickness, replace valve.
Grinding allowance for valve stem tip is 0.2 mm (0.008 in) or
less.
VALVE SPRING
Squareness
1. Measure dimension ªSº.
Out-of-square ªSº:
Less than 2.2 mm (0.087 in)
2. If it exceeds the limit, replace spring.
Pressure
Check valve spring pressure at specified spring height.
Pressure: N (kg, lb) at height mm (in)
Standard
418.0 (42.6, 93.9) at 29.17 (1.1484)
Limit
393.0 (40.1, 88.4) at 29.17 (1.1484)
If it exceeds the limit, replace spring.
SEM892B
SEM621F
SEM188A
SEM288A
EM113
CYLINDER HEADKA24DE
Inspection (Cont'd)
EM-2031

VALVE LIFTER AND VALVE SHIM
1. Visually check contact and sliding surfaces for wear and
scratches.
2. Check diameter of valve lifter and valve lifter guide bore.
Valve lifter outer diameter:
33.960 - 33.975 mm (1.3370 - 1.3376 in)
Lifter guide bore diameter:
34.000 - 34.021 mm (1.3386 - 1.3394 in)
Valve lifter to valve lifter guide clearance:
0.025 - 0.061 mm (0.0010 - 0.0024 in)
If it exceeds the standard diameter or clearance, replace
valve lifter or cylinder head.
Assembly
1. Install valve component parts.
lAlways use new valve oil seal. Refer to ªOIL SEAL
REPLACEMENTº (EM-2021).
lBefore installing valve oil seal, install valve spring seat.
lInstall outer valve spring (uneven pitch type) with its
narrow pitch side toward cylinder head side.
lAfter installing valve component parts, tap valve stem tip
with plastic hammer to assure a proper fit.
Valve Clearance
CHECKING
Check valve clearance while engine is warm but not run-
ning.
1. Remove rocker cover and all spark plugs.
2. Set No. 1 cylinder at TDC on its compression stroke.
lAlign pointer with TDC mark on crankshaft pulley.
lCheck that valve lifters on No. 1 cylinder are loose and valve
lifters on No. 4 are tight.
If not, turn crankshaft one revolution (360É) and align as
above.
AEM410
AEM411
SEM303D
SEM638B
AEM355
CYLINDER HEADKA24DE
Inspection (Cont'd)
EM-2032

3. Check only those valves shown in the figure.
4. Using a feeler gauge, measure clearance between valve lifter
and camshaft.
lRecord any valve clearance measurements which are out of
specification. They will be used later to determine the
required replacement adjusting shim.
Valve clearance (Hot):
Intake
0.31 - 0.39 mm (0.012 - 0.015 in)
Exhaust
0.33 - 0.41 mm (0.013 - 0.016 in)
5. Turn crankshaft one revolution (360É) and align mark on
crankshaft pulley with pointer.
6. Check those valves shown in the figure.
lUse the same procedure as mentioned in step 4.
7. If all valve clearances are within specification, install the fol-
lowing parts.
lRocker cover
lAll spark plugs
ADJUSTING
Adjust valve clearance while engine is cold.
1. Turn crankshaft to position cam lobe on camshaft of valve
that must be adjusted upward.
2. Place Tool (A) around camshaft as shown in figure.
3. Rotate Tool (A) so that lifter is pushed down.
Before placing Tool (A), rotate notch toward center of cylin-
der head (See figure.), to simplify shim removal later.
CAUTION:
Be careful not to damage cam surface with Tool (A).
4. Place Tool (B) between camshaft and the edge of the valve
lifter to retain valve lifter.
CAUTION:
lTool (B) must be placed as close to camshaft bracket as
possible.
lBe careful not to damage cam surface with Tool (B).
5. Remove Tool (A).
AEM382
SEM304D
AEM383
SEM515EB
SEM516EB
CYLINDER HEADKA24DE
Valve Clearance (Cont'd)
EM-2033

6. Rotate adjusting shim until hole is visible. Blow air into the
hole to separate adjusting shim from valve lifter.
7. Remove adjusting shim using a small screwdriver and a
magnetic finger.
8. Determine replacement adjusting shim size as follows.
a. Using a micrometer determine thickness of removed shim.
b. Calculate thickness of new adjusting shim so valve clearance
comes within specified values.
R = Thickness of removed shim
N = Thickness of new shim
M = Measured valve clearance
Intake & Exhaust:
N=R+[Mþ0.37 mm (0.0146 in)]
Shims are available in thicknesses from 1.96 mm (0.0772 in)
to 2.68 mm (0.1055 in), in steps of 0.02 mm (0.0008 in).
c. Select new shim with thickness as close as possible to cal-
culated value.
Refer to SDS, EM-2050.
9. Install new shim using a suitable tool.
lInstall with the surface on which the thickness is
stamped facing down.
10. Place Tool (A) as mentioned in steps 2 and 3.
11. Remove Tool (B).
12. Remove Tool (A).
13. Recheck valve clearance.
Refer to ªCHECKINGº (EM-2032).
SEM999F
SEM517EB
SEM145D
SEM308D
SEM518EB
CYLINDER HEADKA24DE
Valve Clearance (Cont'd)
EM-2034

AEM398
ENGINE REMOVALKA24DE
EM-2035

WARNING:
lPosition vehicle on a flat and solid surface.
lPlace chocks at front and back of rear wheels.
lDo not remove engine until exhaust system has com-
pletely cooled off.
Otherwise, you may burn yourself and/or fire may break
out in fuel line.
lBefore disconnecting fuel hose, release fuel pressure.
Refer to EC section (ªFuel Pressure Releaseº, ªBASIC
SERVICE PROCEDUREº).
lBe sure to hoist engine and transmission in a safe man-
ner.
lFor engines not equipped with engine slingers, attach
proper slingers and bolts described in PARTS CATA-
LOG.
CAUTION:
lWhen lifting engine, be sure to clear surrounding parts.
Take special care near accelerator wire casing, brake
lines and brake master cylinder.
lIn hoisting the engine, always use engine slingers in a
safe manner.
lFor 4WD models, apply sealant between engine and
transmission. Refer to MT section (ªRemoval and Instal-
lationº).
Removal
1. Drain coolant from engine block and radiator. Refer to MA
section (ªChanging Engine Coolantº, ªENGINE MAINTE-
NANCEº).
2. Release fuel pressure. Refer to EC section (ªFuel Pressure
Releaseº, ªBASIC SERVICE PROCEDUREº).
3. Remove negative battery cable.
4. Remove hood. Refer to BT section.
5. Remove air cleaner and air duct.
6. Remove power steering drive belt, alternator drive belt and
A/C compressor drive belt.
7. Remove radiator. Refer to LC section (ªRadiatorº, ªENGINE
COOLING SYSTEMº).
8. Remove exhaust manifold heat shield.
9. Disconnect exhaust system from exhaust manifold.
10. Remove A/C compressor from bracket. Refer to HA section
(ªCompressor Mountingº, ªSERVICE PROCEDURESº).
11. Disconnect accelerator wire, vacuum hoses, electrical
connectors, heater hoses and vacuum booster hose.
ENGINE REMOVALKA24DE
EM-2036