1993 CHEVROLET DYNASTY service

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
cover and tighten fasteners to 12 N Im (105 in. lbs.)
torque (Fig. 4).
CAUTION: Do not use impact wrench on accessory
drive belt tensioner bolt. It may cause damage to
tensioner arm. Accessory drive belt tensioner pul-
ley bolt must be installed finger tight. (2) Install accessory drive belt tensioner pulley
bolt finger tight. Then tighten bolt to 54 N Im (40 ft.
lbs.) torque (Fig. 4). (3) Install crankshaft and water pump pulleys
(Fig. 3). (4) Install inner splash shield and wheel (Fig. 2).
(5) Install accessory drive belt. Refer to Cooling
System Group 7 for procedure. (6) Install upper timing belt cover and tighten
screws to 4 N Im (36 in. lbs.) torque. Install PCV tube
(Fig. 1).
TIMING BELT
REMOVAL
(1) Remove timing belt cover refer to timing belt
cover service of this section for procedure. (2) Lift engine with Engine Support Tool C-4852.
Separate right engine mount (Fig. 5). (3) Raise vehicle on a hoist. Remove lower acces-
sory drive belt idler pulley bracket assembly (Fig. 6). (4) Loosen timing belt tensioner, remove timing
belt and idler pulley (Fig. 6). (5) Lower vehicle
Fig. 4 Timing Belt Cover and Tensioner
Fig. 5 Right Engine MountÐTypical
Fig. 6 Remove Timing Belt
Ä 2.2/2.5L ENGINE 9 - 33

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 about 3 turns as shown in (Fig. 8).
CAUTION: Check lash adjuster for loose or missing
retainers before continuing service procedure.
(4) Align and pin both intake and exhaust cam
sprockets with 3/32 drills or pin punches (Fig. 9). Ac-
cessory Shaft does not need to be timed. (5) Remove spark plugs.
(6) Install a dial indicator in Number 1 spark plug
hole (Fig. 10). (7) Rotate crankshaft till number 1 piston is at
Top Dead Center. Mark the engine block for TDC
reference. (8) Install timing belt and idler pulley in sequence
shown in (Fig. 11). (9) Remove dial indicator from cylinder head (Fig.
10). Remove drills or pins from camshaft sprockets
(Fig. 11). (10) Adjust tension to 445 N (110 lbs.)
New beltor
311 N (70 lbs.) Used belt. Install belt tension gauge on
timing belt (Fig. 12) adjust tensioner until specified
tension is achieved.
CAUTION: Belt tension gauge must be installed be-
tween the belt teeth to get a accurate reading .
(11) Rotate crankshaft clockwise 2 full revolutions
and check alignment of camshaft and crankshaft tim-
ing marks. Do not reverse rotate crankshaft or
attempt to rotate engine using cam or accessory
shaft attaching screw.
CAUTION: Do not allow oil or solvents to contact the
timing belt as they can deteriorate the rubber and
cause tooth skipping.
Fig. 7 Ignition Cable Cover
Fig. 8 Rocker Arm Shaft Assemblies
Fig. 9 Camshafts Pinned Into Position
Fig. 10 Dial Indicator Located in Number 1 Cylinder
9 - 34 2.2/2.5L ENGINE Ä

(12) Recheck belt tension, adjust if necessary.
(13) Torque rocker arm shafts in sequence shown
(Fig. 13) to 12 N Im (105 in. lbs.) then to 24 N Im (210
in. lbs.). (14) Install valve covers, spark plugs, ignition cables
and ignition cable cover. (15) Install air cleaner fresh air duct.
(16) Raise vehicle. Install lower timing belt cover
and accessory drive belt tensioner pulley. Refer to
procedure in this section. (17) Lower vehicle. Install right engine mount (Fig.
5). (18) Inspect foam stuffer block condition and posi-
tion (Fig. 14). Stuffer block should be intact and secure
within the engine bracket tunnel. (19) Install upper timing belt cover and PCV tube.
Refer to procedure in this section. (20) Install accessory drive belt. Refer to procedure
in this section.
SERVICING OIL SEALS
Refer to servicing oil seals in this group for proce-
dures. To service the intake cam seal (Turbo III) the
right engine mount must be removed. Refer to
engine mount removal of this Group.
Fig. 13 Rocker Arm ShaftÐInstallation
Fig. 14 Foam Stuffer Block Location
Fig. 11 Camshafts and Crankshaft Timing Marks
Fig. 12 Belt Tension Gauge Location
Ä 2.2/2.5L ENGINE 9 - 35

CAMSHAFTS SERVICE
Cylinder Head must be removed from vehicle. Re-
fer to cylinder head removal for procedure.
REMOVAL
(1) Mark rocker arms shafts for reinstallation in
the same position (Fig. 1). (2) Remove rocker arm assembly attaching bolts in
sequence (Fig. 1 ). (3) Remove thrust plates from rear of camshafts
(Fig. 2).The intake camshaft uses a wider thrust
plate than exhaust camshaft.
CAUTION: Thrust plates are not the same thickness
and cannot be interchanged.
(4) Before camshaft can be removed from cylinder
head the cam seal must be removed first. Becareful
not to damage seal surface of the camshaft. (5) Using a screwdriver place it against the side of
the cam lobe push the cam out of the head. The cam
seal will be pushed out by the cam (Fig. 3). (6) Slide the camshaft out of the cylinder head. Be-
careful not scratch the bearing surfaces in the head
(Fig. 4).
CAUTION: Intake and Exhaust camshafts are not in-
terchangeable .
INSPECTION
Camshaft lobe wear should not exceed .25mm (.010
inch). To measure cam lobe wear (Fig. 4), measure
lobe diameter in two places at the largest diameter
(over the nose). Take first reading with micrometer
in unworn area at the edge of the lobe. Take second
reading in the worn area where rocker arm contacts
the lobe. Subtract second reading from the first. The
difference is the cam lobe wear.
INSTALLATION
(1) Lubricate camshaft journals with clean engine
oil. Carefully install camshaft into the head.
CAUTION: Camshafts are not interchangeable. The
intake cam has a wider thrust plate groove.
Fig. 3 Removing Camshaft Oil Seal
Fig. 1 Rocker Arm Shaft Removal Sequence
Fig. 2 Camshaft Thrust Plates
Fig. 4 CamshaftÐRemoval or Installation
9 - 36 2.2/2.5L ENGINE Ä

(2) Install thrust plates and tighten retaining nuts
to6N Im (55 in. lbs.).
(3) Install new camshaft oil seals flush with cylin-
der head surface. Using seal installing special tool C-4680.
CAMSHAFT END PLAY
(1) Using a suitable tool, move camshaft as far
rearward as it will go. (2) Zero dial indicator (Fig. 6).
(3) Move as far forward and backward as camshaft
will go. (4) End play travel: 0.025-0.200mm (.001-.008
inch).
LASH ADJUSTER (TAPPET) NOISE
A tappet-like noise may be produced from several
items. See Lash Adjuster and Tappet Noise-DIAG-
NOSIS in STANDARD SERVICE PROCEDURES,
this Group.
VALVE COMPONENTS REPLACEÐCYLINDER HEAD
NOT REMOVED
ROCKER ARM AND HYDRAULIC LASH
ADJUSTER
REMOVAL
(1) Remove valve cover. Refer to procedure previ-
ously outlined in this section.
(2) Remove rocker arm shaft(s) in sequence shown
in (Fig. 6). Slide rocker off the shaft. Keep rocker
arms in order for reassembly.
CAUTION: Check lash adjusters for loose or miss-
ing retainers before continuing service procedure.
(3) Remove hydraulic lash adjuster.
Fig. 5 Measuring Camshaft Lobe Wear
Fig. 6 Checking Camshaft End Play
Fig. 7 Rocker Arm ShaftÐRemoval
Fig. 8 Rocker Arm and Lash Adjuster AssemblyÐRight and Left
Ä 2.2/2.5L ENGINE 9 - 37

INSTALLATION (1) Install rocker arm on the shaft in there origi-
nal position (Fig. 9). (2) Install hydraulic lash adjusters making sure
that adjusters are at least partially full of oil. This is
indicated by little or no plunger travel when the lash
adjuster is depressed. (3) Install rocker arm shaft assembly tighten in se-
quence shown in (Fig. 10). (4) Install valve cover as previously outlined.
VALVE SPRINGS AND VALVE STEM SEALS
VALVE SERVICE
² CYLINDER HEAD MUST BE REMOVED TO
SERVICE VALVE SPRINGS AND VALVE STEM
SEALS.
VALVES AND VALVE SPRINGS
REMOVAL
(1) With cylinder head removed, compress valve
springs using Valve Spring Compressor Tool
C-3422-B with adopters 6537 and 6526 (Fig. 11). (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. Refer to (Fig. 14)
for specifications. (3) Remove carbon and varnish deposits from inside
of valve guides with a reliable guide cleaner.
VALVE GUIDES
Measure valve guides in 3 places top, middle and
bottom (Fig. 13). Using a small hole gauge and a
micrometer, refer to (Fig. 12) for specifications. Replace cylinder head if guides are not within
specifications.
TESTING VALVE SPRINGS
(1) Refer to Testing Valve previously described in
this Group for procedure. Test springs at 36.8 mm
(1-7/16 to 1-15/32 in.) 1000 N (225 lbs.) 640 N (9 lbs.).
Discard the springs that do not meet specifications. (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 1.65mm (1/16 inch) out
of square, install a new spring. Spring free length is
53.2 mm 6.25 mm (2.094 in. 6.010 in.)
Fig. 9 Intake and Exhaust Rocker Arm Assemblies
Fig. 10 Rocker Arm ShaftÐInstallation
Fig. 11 Valve Spring Compressor
Fig. 12 Valve Guide Specification
9 - 38 2.2/2.5L ENGINE Ä

VALVE GEAR REASSEMBLY AFTER VALVE SERVICE
(1) Coat valve stems with lubrication oil and insert
in cylinder head. (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. (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 Valve Spring Compressor Tool C-3422-B
with adopters 6537 and 6526 (Fig. 11) the locks can
become dislocated. Check to make sure both locks
are in their correct location after removing tool.
(4) Check installed height of springs. Measurement
B is to be taken from the spring seat to the bottom of
the spring retainer. Correct height is 44.0mm (1.73
inches). If seats have been ground an additional
spring seat may be required to maintain correct in-
stalled spring height (Fig. 17). (5) Install camshaft and rocker arms as previously
described, see Camshaft-Install.
Fig. 17 Checking Valve Tip Height and Spring Installed Height
9 - 40 2.2/2.5L ENGINE Ä

CRANKSHAFT, INTERMEDIATE AND BALANCE SHAFT SERVICE
Fig. 1 Crankshaft Intermediate and Balance Shaft Assemblies and Oil Seals
Ä 2.2/2.5L ENGINE 9 - 41