1993 CHEVROLET DYNASTY Service Manual

air conditioning fuses fuel filter location lug pattern remote control ad blue

Page 1593 of 2438

CHEVROLET DYNASTY 1993 Service Manual Cylinder Head: Top of bearing caps painted green
and O/SJ stamped rearward of oil gallery plug on end
of head. Camshaft: Barrel of camshaft painted greenand
O/SJ stamped on end of shaft.
CLEANING

Page 1594 of 2438

CHEVROLET DYNASTY 1993 Service Manual springs using Tool C-3422-B. (2) Remove valve retaining locks, valve spring re-
tainers, valve stem seals and valve springs. (3) Before removing valves, remove any burrs
from valve stem lock grooves

springs using Tool C-3422-B. (2) Remove valve retaining locks, valve spring re-
tainers, valve stem seals and valve springs. (3) Before removing valves, remove any burrs
from valve stem lock grooves to prevent damage
to the valve guides. Identify valves to insure instal-
lation in original location.
VALVE INSPECTION (1) Clean valves thoroughly and discard burned,
warped and cracked valves. (2) Measure valve stems for wear.
(3) If valve stems are worn more than 0.05 mm (.002
inch.) replace valve.
VALVE GUIDES
(1) Remove carbon and varnish deposits from inside
of valve guides with a reliable guide cleaner. (2) Checking Valve Guide Wear:
² Insert valve with valve head positioned 10 mm (.400
inch) above cylinder head gasket surface.
²
Move valve to and from the indicator (Fig. 17). The
total dial indicator reading should not exceed the amount
specified in (Fig. 18). Readings should be taken for length-
wise and crosswise (with respect to cylinder head) move-
ment for each valve. Ream the guides for valves with
oversize stems if dial indicator reading is excessive or if
the stems are scuffed or scored.
(3) Service valves with oversize stems and oversize
seals are available in 0.15mm, (.005 inch) 0.40mm,
(.015 inch) and 0.80mm(.031 inch) oversize. Oversize seals must be used with oversize
valves. Reamers sizes to accommodate the oversize valve
stem are shown in (Fig. 18)
(4) Slowly turn reamer by hand and clean guide thor-
oughly before installing new valve. Do not attempt to
ream the valve guides from standard directly to
0.80mm (.030 inch). Use step procedure of 0.15mm
(.005 inch), 0.40mm (.015 inch) and 0.80mm (.030 inch) so the valve guides may be reamed true in
relation to the valve seat. After reaming guides, the
seat runout should be measured and resurfaced if
necessary. Refer to Refacing Valves and Valve Seats.
Replace cylinder head if guide does not clean
up with 0.80 mm (.030 inch) oversize reamer, or if
guide is loose in cylinder head.
TESTING VALVE SPRINGS
(1) Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should be
tested. As an example, the compression length of the
spring to be tested is 33.34mm (1-5/16 inches). Turn table
of Tool C-647 until surface is in line with the 33.34mm
(1-5/16 inch) mark on the threaded stud and the zero
mark on the front. Place spring over stud on the table and
lift compressing lever to set tone device (Fig. 20). Pull on
torque wrench until ping is heard. Take reading on torque
wrench at this instant. Multiply this reading by two. This
will give the spring load at test length. Fractional mea-
surements are indicated on the table for finer adjust-
ments. Refer to specifications to obtain specified height
and allowable tensions. Discard the springs that do not
meet specifications.
Fig. 18 Checking Wear on Valve GuideÐTypical
Fig. 19 Valve Guide Specification
Fig. 20 Testing Valve Spring with Tool C-647
9 - 28 2.2/2.5L ENGINE Ä

Page 1595 of 2438

CHEVROLET DYNASTY 1993 Service Manual (2) Inspect each valve spring for squareness with a
steel square and surface plate, test springs from both
ends. If the spring is more than 1.5mm (1/16 inch)
out of square, install a new spring.
REF

(2) Inspect each valve spring for squareness with a
steel square and surface plate, test springs from both
ends. If the spring is more than 1.5mm (1/16 inch)
out of square, install a new spring.
REFACING VALVES AND VALVE SEATS (1) The intake and exhaust valve seats and valve
face have a 45 degree angle.
(2) Inspect the remaining margin after the valves are
refaced (Fig. 23). Exhaust valves with less than
1.191mm (3/64 inch) margin and intake valves with less
than .794mm (1/32 inch) margin should be discarded. (3) When refacing valve seats, it is important that
the correct size valve guide pilot be used for reseating
stones. A true and complete surface must be obtained.
(4) Measure the concentricity of valve seat using a
valve seat dial indicator. Total runout should not ex-
ceed. 051mm (.002 inch) (total indicator reading).
(5) Inspect the valve seat with Prussian blue to deter-
mine where the valve contacts the seat. To do this, coat
valve seat LIGHTLY with Prussian blue then set valve
in place. Rotate the valve with light pressure. If the
blue is transferred to the center of valve face, contact is
satisfactory. If the blue is transferred to top edge of the
valve face, lower valve seat with a 15 degrees stone. If
the blue is transferred to the bottom edge of valve face
raise valve seat with a 65 degrees stone.
² Intake valve seat diameter 40.45mm (1.593 inch)
² Exhaust valve seat diameter 34.84mm (1.371 inch)
Valve seats which are worn or burned can be re-
worked, provided that correct angle and seat width are
maintained. Otherwise cylinder head must be replaced.
(6) When seat is properly positioned the width of
intake seats should be 1.75 to 2.25mm (0.69 to .088
inch) The width of the exhaust seats should be 1.50
to 2.00mm (.059 to .078 inch) (Fig. 24 Dimension 1).
(7) Check valve tip to spring seat dimensions after
grinding the valve seats or faces. Grind valve tip to get
49.76 to 51.04mm (1.960 to 2.009 inch) over spring seat
when installed in the head (Fig. 25). The valve tip di-
ameter should be no less than 7.0mm (0.275 inch), if
necessary, the tip chamfer should be reground to pre-
vent seal damage when the valve is installed.
Fig. 21 Intake and Exhaust Valves
Fig. 22 Valve Dimensions
Fig. 23 Refacing Intake and Exhaust Valves
Fig. 24 Refacing Valve Seats
Ä 2.2/2.5L ENGINE 9 - 29

Page 1596 of 2438

CHEVROLET DYNASTY 1993 Service Manual (8) Check the valve spring installed height after
refacing the valve and seat (Fig. 26).
CAUTION: If more than .5mm (.020 inch) must be
ground from the valve tip, check the clearance be-
tween the

(8) Check the valve spring installed height after
refacing the valve and seat (Fig. 26).
CAUTION: If more than .5mm (.020 inch) must be
ground from the valve tip, check the clearance be-
tween the rocker arm and the valve spring retainer
if below 1.25mm (.050 inch), grind the rocker arm
ears according to the procedure described in Refac-
ing Valves and Valve Seats.
CLEANING
Clean all valve guides, valves and valve spring as-
semblies thoroughly with suitable cleaning solution
before reassembling.
VALVE GEAR REASSEMBLY AFTER VALVE SERVICE (1) Coat valve stems with lubrication oil and insert
in cylinder head. CAUTION: Flexible Fuel Vehicles use unique valve
stem oil seals they are green in color. Standard
valve stem oil seals are NOT to be interchanged with
Flexible Fuel Vehicles engines.
(2) Install new valve stem seals on all valves. The
valve stem seals should be pushed firmly and
squarely over valve guide. The lower edge of the seal
should be resting on the valve guide boss.
CAUTION: When oversize valves are used, the cor-
responding oversize valve seal must also be used.
Excessive guide wear may result if oversize seals
are not used with oversize valves.
(3) Install valve spring seats and springs and re-
tainers. Compress valve springs only enough to in-
stall locks, taking care not to misalign the direction
of compression. Nicked valve stems may result from
misalignment of the valve spring compressor.
CAUTION: When depressing the valve spring retain-
ers with Tool C-3422-B the locks can become dislo-
cated. Check to make sure both locks are in their
correct location after removing tool .
(4) Check installed height of springs. Measurement
is to be taken from the spring seat to the bottom of
the spring retainer. Correct height is 41.2mm to
42.7mm (1.62 to 1.68 inches). If seats have been re-
ground an additional spring seat may be required to
maintain correct installed spring height. (5) Install adjusters, rocker arms in order, and
camshaft as previously described, see Camshaft-In-
stall. Check for clearance between the projecting ears
(either side of valve tip) of the rocker arms and the
valve spring retainers. At least 1.25 mm (.050 inch)
clearance must be present, if necessary, the rocker
arm ears may be ground to obtain this clearance
(Fig. 26). (6) Checking dry lash. Dry lash is the amount of
clearance that exists between the base circle of an in-
stalled cam and the rocker arm roller when the ad-
juster is drained of oil and completely collapsed.
Specified dry lash is 0.62 to 1.52 mm (.024 to .060
inch). To completely collapse adjuster for dry lash
measurement, pry off retainer cap, disassemble,
drain the adjuster of oil, reassemble, and install. Af-
ter performing dry lash check, refill adjuster with oil
(do not reuse retainer cap/s) and allow 10 minutes for
adjuster/s to bleed down before rotating cam.
Fig. 25 Valve Tip to Spring Seat Dimensions
Fig. 26 Checking Spring Installed Height and Spring Retainer Clearance
9 - 30 2.2/2.5L ENGINE Ä

Page 1597 of 2438

CHEVROLET DYNASTY 1993 Service Manual CYLINDER HEAD AND VALVE ASSEMBLY
SERVICEÐTURBO III
CYLINDER HEAD COVER SEALING
(1) Before installation, clean cylinder head and cover
mating surfaces. Make certain rails are flat.
Caution: Do not

Page 1598 of 2438

CHEVROLET DYNASTY 1993 Service Manual Before installing the bolts, the threads should be
cleaned and oiled. Tighten the cylinder head bolts in the sequence
shown in (Fig. 5 ). Using the 4 step torque turn
method, tighten according to the

Page 1599 of 2438

CHEVROLET DYNASTY 1993 Service Manual CAUTION: Do not use a impact wrench to remove
pulley bolts. (6) Remove lower timing belt cover fasteners (Fig.
1). Remove cover.
INSTALLATION (1) Raise vehicle on hoist. Install lower timing belt

Page 1600 of 2438

CHEVROLET DYNASTY 1993 Service Manual CAMSHAFT AND CRANKSHAFT TIMING
PROCEDURE
INSTALLATION
(1) Remove air cleaner fresh air duct.
(2) Remove ignition cable cover (Fig. 7).
(3) Remove valve covers and loosen rocker arm as-
semblies abou

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