GMC T Series 1994 Repair Manual page 548

m
Measure
• Timing chain free play as follows:
1. Mount a dial indicator to the front of the block.
2. Position the dial indicator so that the plunger
contacts the timing chain between the two
sprockets.
3. Pull the chain outward (parallel to the front face
of the block) the maximum amount with finger
pressure on the inside of the chain.
4. Set the dial indicator to zero.
5. Move the chain inward (parallel to the front face
of the block) the maximum amount with finger
pressure on the outside of the chain.
6. The total indicator travel can be noted. With
used parts, the deflection must not exceed 20.3
mm (0.80 inch). If the deflection exceeds this
limit, the sprockets and timing chain must be
inspected for wear and replaced as necessary.
With new parts, the deflection must not exceed
12.7 mm (0.50 inch).
FRONT COVER INSTALLATION
Clean
Sealing surfaces on the block and front cover with
carburetor cleaner or equivalent.
I?
Inspect
• Torsional damper hub sealing surface for dam­
age. Replace if necessary.
+«-
Install or Connect (Figures 66 and 67)
N O T IC E : F o r s t e p s 1 a n d 2 , r e f e r to " N o t ic e "
o n p a g e 6 A 7 -1 .
• Apply a 2-mm (3/32-inch) bead of anaerobic
sealant (GM P/N 1052357) or equivalent to the
front cover sealing area shown in figure 66.
1. Front cover to the engine. Install the bolts (70).
St Tighten
• Bolts (70) to 45 N m (33 lbs. ft.).
2. Crankshaft sensor with new O-ring seal.
Tighten
Retaining bolt to 25 N-m (17 lbs. ft.).
Important
• If a new front cover was installed, mark TDC on
the cover as outlined following. This is neces­
sary to provide a reference mark for timing the
injection pump.
TORSIONAL DAMPER
INSTALLATION
Install or Connect (Figure 66)
• Before installing the torsional damper, check oil
seal contact area for grooving and roughness.
Replace damper if necessary.
1. Torsional damper (55). Tap into place with a mallet.
Make sure the key is in place. Make sure the
damper is all the way on the crankshaft.
N O T IC E : R e f e r to " N o t i c e " o n p a g e 6 A 7 -1 .
2. Bolt (56) and washer (57).
Tighten
• Bolt (56) to 270 N.m (200 lbs. ft.).
HYDRAULIC LIFTER
INSTALLATION
• When installing a new camshaft the lifters must be
replaced.
•S o m e eng in e s w ill have both standard and
0.010-inch oversize hydraulic lifters. The oversize
lifter will have a " 10" etched on the side. The block
70
46. COVER, FRONT CRANKCASE
48. POINTER, TIMING
49. SCREW, TIMMING POINTER
50. PLATE, COOLANT PUMP
52. GASKET, COOLANT PLATE
54. BOLT, COOLANT PUMP/PLATE
55. DAMPER, TORSIONAL
56. BOLT, TORSIONAL DAMPER
57. WASHER
58. BOLT/STUD
269 72
, PUMP, COOLANT
. TABLE, OIL FILL
, NUT
. GROMMET
BOLT/STUD
BOLT
BOLT
NUT
BAFFLE
SENSOR,
!
CRANKSHAFT
3706r5726