Cylinder HeadValve Seats
Warpage
NOTE: lf the camshaft-to-holder oil clearances (see
page 6-36) are not within specification, the cylinder head
cannot be resurfaced.
lf the camshaft-to-holder oil clearances are within sDeci,
fications, check the cylinder head lor warpage.
lf warpage is less than 0.05 mm (0.002 in), cylin-
der head resurfacing is not required.
lf warpage is between 0.05 mm (0.002 in) and
0.2 mm {0.008 in), resurface the cylinder head.
Maximum resurface limit is 0,2 mm (0.008 in)
based on a height of 93 mm (3.66 in).
Measure along edges, and three ways across center.
Cylinder Head Height:
Standard {Newl: 92.95 - 93.05 mm
{3.659 - 3.66:} in)
6-40
\
Reconditioning
'1. Renew the valve seats in the cylinder head using a
valve seat cutter.
NOTE: lf the guides are worn (see page 6-39).
replace them (see page 6-41) belore cutting the
valve seats.
VALVE SEATCUTTER(Commercially available)
2.
?
4.
Carefully cut a 45'seat, removing only enough
material to ensure a smooth and concentric seat.
Bevel the upper edge of the seat with the 30. cutter
and the lower edge of the seat with the 60' cutter.
Check the width of the seat and adjust accordingly.
Make one more very light pass with the 45" cutter to
remove any possible burrs caused by the other cut-
Iers.
Valve Seat Width:
Standard (N€w):
Intake: 0.85 - 1.15 mm 10.033 - 0.045 in)
Exhaust: 1.25 - 1.55 mm {0.049 - 0.061 in}
Sorvice Limit:
Intake: 1.6 mm (0.063 inl
Exhausl: 2.0 mm (0.079 in)
Seat Width
5. After resurfacing the seat, inspect for even valve
seatingr Apply Prussian Blue compound to the
valve face, and insert the valve in its original loca-
tion in the head, then liit and snap it closed against
the seat several times.
Valve Guides
7.
VALVESEAT
PFUSSIAN BTUE COMPOUNO
The actual valve seating surface. as shown by the
blue comDound, should be centered on the seat.
. lf it is too high (closer to the valve stem), you
must make a second cut with the 60'cutter to
move it down, then one more cut with the 45'
cutter to restore seat width,
. lf it is too low (closer to the vslve edge), you
must make a second cut with the 30" cutter to
move it uD, then one more cut with the 45'cutter
to restore seat width.
NOTE: The final cut should always be made with
the 45" cutter.
lnsert the intake and exhaust valves in the head and
measure the valve stem installed height.
Intake. Exhau3t Siem Installsd Height:
Standard (New): 53.17 - 53.6,4 mm
12.093 - 2.112 in)
Sorvice Limit: 53.89 mm (2.122 in)
lf the valve stem installed height is over the service
limit. reDlace the valve and recheck. lf its still over
the service limit, replace the cylinder head; the
valve seat in the head is too deep.
VALVE STEMINSTALLED HEIGHT
8.
\-
Replacement
1.As illustrated below, use a commercially-available
air-impact valve guide driver attachment modified
to fit the diameter of the valve guides. In most cases.
the same procedure can be done using the special
tool and a conventional hammer.
VALVE GUIDE DRIVERlCommerciallv available)5.3 mm
87 mm +- 57 mft
t3.43 in) | 12 24 inl
tr-r'10.8 mm(0.42 inl
or
VALVE GUIDE DRIVER, 5.5 mm
07742 - 0010100
Select the proper replacement guides. and chill them
in the freezer section of a refrigerator for about an
nour.
Use a hot plate or oven to evenly heat the cylinder
head to 300"F (150'C). Monitor the temperature with
a cooking thermometer.
CAUTION:
. Do not use a torch; it may warp the head.
Do not got the head hottel than 300"F (150"C1;
excessive heat may loosen thg valve seats.
To avoid burns. use heayy gloves whon handling
the heated cylinder h€ad.
{cont'd)
6-41
Valve Guides
Replacement (cont'd)
Working from the camshaft side, use the driver andan air hammer to drive the guide about 2 mm (0.1 in)towards the combustion chamber. This will knock offsome of the carbon and make removal easier.
CAUTION:
. Always wear satety goggles or a face shield when
driving valve guides.
. Hold the air hammer directly in line with thevalve guide to prevent damaging the driver.
Turn the head over, and drive the guide out towardthe camshaft side of the head.
VALVE GUIOE ORIVER,5.5 mm07742 - 001 01 00
It a valve guide still won't move, drill it out with a8 mm {5/16 in) bit, then try again.
CAUTION: Drill guides only in extreme cases; you
could damage the cylinder head it the guide breaks.
6. Remove the new guides from the freezer, one at atime, as you need them.
6-42
I7. Apply a thin coat of clean engine oil to the outsideof the new valve guide. Install the guide from thecamshaft side of the head; use the special tool todrive the guide in to the specified insralled height. lfyou have all 16 guides to do, you may have to reheat
the head.
VALVE GUIOEDRIVER,5.5 mm07742 - 0010100
ll
Valve Guide lnstalled Height:
Intake: 17.85 - 18.35 mm (0.703 - 0.722 inl
Exhausi: 18.65 - 19.15 mm (0.734 - 0.754 in)
VALVE GUIDE
Gamshafts
Inspection (cont'dl
7. lf the camshaft-to-holder oil clearance is out of tol-
erance:
- And the camshaft has already been replaced, you
must replace the cylinder head.- lf the camshaft has not been replaced, first check
the total runout with the camshaft supported on
V-blocks.
Camshaft Total Runout:
Standard (New): 0.03 mm {0.001 in} max.
Service Limit: 0.04 mm (0.002 inl
- lf the total runout of the camshaft is within toler,
ance, replace the cylinder head.- lf the total runout is out of tolerance. replace the
camshaft and recheck the camshaft to,holder oil
clearance. lf the oil clearance is still out of toler-
ance, replace the cylinder head.
INTAKEEXHAUST
PRIMARY33.088 mm
{1.3027 in)
32.785 mm
(1.2907 inl
MID36.267 mm(1.4278 in)
35.720 mm
{1.4063 in)
SECONDARY34.978 mm(1.3771 inl
3i1.691 mm(1.3658 in)
8. Check the cam lobe height.
Cam lobe height standard (New):
Cam Position
I
INTAKE
MID
EXHAUST
SEC MID PRI
TIB
T/B: TIMING BELTPRI: PRIMARYMID: MID
Check thrs area lor wear.
Valve Seats
Reconditioning
1. Renew the valve seats in the cylinder
valve seat cutter.
NOTE: lf any guides are worn (see
replace them (see page 6-80) before
valve seats,
head with a
page 6-79),
cutting the
Carefully cut a 45o seat, removing only enough mate-
rial to ensure a smooth and concentric seat.
Bevel the upper edge of the seat with the 30" cutterand the lower edge of the seat with the 60. cutter.Check width of seat and adjust accordingly,
Make one more very light pass with the 45" cutter toremove any possible burrs caused bv the other cut-
ters.
Valve Seat Width:
Standard (Newl: 1.25 - 1.55 mm {0.0't9 - 0.061 in)Service Limii: 2.0 mm 10,08 inl
Sear Widrh
6-78
5. After resufacing the seat. inspect for even valveseating: Apply Prussian Blue Compound to thevalve face, and insert the valve in its original loca-tion in the head. then lift it and snap it closedagainst the seat several times.
PRUSSIAN BLUE COMPOUND
The actual valve seating surface, as shown by theblue compound, should be centered on the seat.. lf it is too high (closer to the valve stem), you mustmake a second cut with the 60. cutter to move itdown, then one more cut with the 45. cutter torestore seat width.
. lf it is too low (closer to the valve edge), you must
make a second cut with the 30. cutter to move itup. then one more cut with the 45. cutter to restoreseat width.
NOTE: The final cut should always be made withthe 45" cutter,
7. Insen the intake and exhaust valves in the head and
measure valve stem installed heioht.
Intaka Valve Stem Installed Height:
Standsrd lNaw): 37.465 - 37.935 mm(1./P50 - r.4935 inl
Sorvice Limit: 38.185 mm 0.5033 in)
Exhau3t Valv€ Stem Installed Height:
Standard (New): 37.165 - 37.6i|5 mm(1.46:t2 - 1.i1817 inl
Servico Limit 37.885 (1.4915 inl
lf valve stem installed height is over the service limit,replace the valve and recheck. lf it is still over the ser-vice limit, replace the cylinder head; the valve seat inthe h6ad is too deep.
(
Cylinder HeadValve Guides
Warpage
NOTE: lf camshaft-to-holder oil clearances (see page 475)
are not within specification, the head cannot be resurfaced.
lf camshaft-to-holder oil clearances are within specifica-
tions, check the head for warPage.
. lf warpage is less than 0.05 mm (0.002 in) cylinder
head resurfacing is not required.
. lf warpage is between 0.05 mm (0.002 in) and 0 2 mm
(0.008 in), resurface cylinder head
. Maximum resurface limit is 0.2 mm (0.008 in) based
on a height of 142 mm (5.59 in).
PRECISION STRAIGHT EDGE
Measure along edges, and three ways across center'
Cylinder Head Height:
Standard lNewl: 1i11.95 - 142.05 mm
15.589 - 5.593 in)
Valve Movement
Measure the guide-to-stem clearance with a dial indica-
tor while rocking the stem in the direction of normal
thrust (wobble method).
lntake Valve Stem-to-Guide Cl6arance:
Standard (Newl: 0.05 - 0.11 mm
(0.0020 - 0.0043 inl
Service Limit: 0.15 mm {0.0059 inl
Exhaust Valve Stem-to-Guide Clealance:
Standard lNewl: 0.10 - 0.16 mm
(0.0039 - 0.0063 inl
Service Limit: 0.24 {0.0094 in)
Valve extended 10 mm out from seat.
lf the measurement exceeds the service limit, recheck
using a new valve.
lf the measurement is now within the service limit.
reassemble using the new valve
lf the measurement still exceeds the limit. recheck using
the alternate method below. then replace the valve and
guide, if necessary.
NOTE: An alternate method of checking guide to stem
clearance is to subtract the o.D. of the valve stem, mea-
sured with a micrometer, from the l.D. of the valve guide,
measured with an inside micrometer or ball gauge.
Take the measurements in three places along the valve
stem and three places inside the valve guide.
The difference between the largest guide measurement
and the smallest stem measurement should not exceed
the service limit.
lntake Valv€ Stem-to-Guide Clsarance:
Standard lNswl: 0.025 - 0.055 mm
10.0010 - 0.0022 inl
service Limit: 0.08 mm (0.003 in)
Exhaust Valve Stem-to Guide Cl€arance:
Standard {Newl: 0.050 - 0.080 mm
{0.0020 - 0.0031 inl
Service Limit 0.ll mm (0.004 in)
6-79
7. Apply a thin coat of clean engine oil to the outside
of the new valve guide. Install the guide from the
camshaft side of the head; use the special tool to
drive the guide in to the specified installed height. lf
you have all l6 guides to do, you may have to reheat
the head,
VALVE GUIDE DRIVER,5.5 mm077i12 - (x)l01(x)
tr A\
Valve Guide Installed Hoight:
lntake: 12.55 - 13.05 mm {0.,194 - 0.514 in)
Exhaust: 12.55 - 13.05 mm 10.494 - 0.51'l in)
VALVE GUIDE
\
Reaming
NOTE: For new valve guides onlY.
1. Coat both reamer and valve guide with cufting oil.
2. Rotate the reamer clockwise the full length of the
valve guide bore.
Continue to rotate the reamer clockwise while
removing it from the bore
Thoroughly wash the guide in detergent and water
to remove any cutting residue.
Check clearance with a valve lsee page 6-73)
. Verify that the valve slides in the intake and
exhaust valve guides without exertlng pressure.
REAMER HANDLE
Turn r6amer in
clockwise direction
a
VALVE GUIOE REAMER. 5.5 mm
OTHAH - PJTO1IIB
6-81
EGT Switch
-f
Testing
Replace the thermostat if it is open at room temperature'
To test a closed thermostat:
1, Suspend the thermostat in a container of water as
shown.
THEBMOMETER
THERMOSTAT
Heat the water, and check the temperature with a
thermometer. Check the temperature at which the
thermostat first opens, and at which it is fully open
CAUTION: Do not let the thermometer touch the
bottom of the hot Gonlainel.
Measure lift height of the thermostat when fully
open.
STANDARD THERMOSTAT
Lift height above 8.0 mm (0.31 inl
Starts opsning: 169' - 176'F (76' - 80'Cl
Fully open: 194'F {90"C1
!'o
10-1 1
Testing
!!@ Romoving the EcT swhch while lhs engine
i!-ot can cause the coolant to sPray out, seriously scald-
ing you. Always lst th€ ongine and rediator cool down
before removing ihe ECT switch.
NOTE: Bleed air from the cooling system after installing
the ECT switch (see Page 10-7)
1. Remove the ECT switch from the thermostat hous-
ing (see Page'10-10).
2. Suspend the ECT switch in a container of water as
shown.
Heat the water, and check the temperature with a
thermometer.
CAUTION: Do not let the thermomoter touch tho
bottom of the hot container'
Measure the resistance between the A and B termi-
nals according to the table.4.
Terminal
Oo"rffi
swlTcH
ON196' - 203"F
(91" - 95'C)o--o
OFF
5" - 15'F {3" - 8'C)
lower than the temPera-
ture when t goes on