Cylinder B O R E; Piston And Connecting Rod A S S E M B Lie; Intake And Exhaust Manifolds - Chevrolet 1988 Light Duty Truck Repair Manual

Figure 24— Checking the Block Gasket Surface
provide the same dim ension as at the other
bores. This is necessary to assure the proper
" crush" on bearing inserts when the engine is
assembled.
CYLINDER BORES
y | In sp ect
• C ylinder walls for scoring or other damage.
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C ylinder out of round and taper. Refer to GENERAL
ENGINE M ECHANICAL (SEC. 6A).
CYLINDER BORE RECONDITIONING
Refer to GENERAL ENGINE M ECHANICAL (SEC. 6A).
Figure 25— Main Bearing Cap Shim Location
4.8 LITER L6 6A4-15
PISTON AND CONNECTING ROD
ASSEMBLIES
Refer to GENERAL ENGINE M ECHANICAL (SEC. 6A)
and perform the following:
*
D isassem b le
Com ponents as required.
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Com ponents as outlined.
lV
In sp ect
C om ponents as outlined.
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• Piston pin diam eter and pin to piston clearance.
• Piston to bore clearance, and fit pistons as outlined.
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A ssem b le
• Com ponents as outlined.
m
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Ring end gap and ring clearance.
L*
Inspect
Ring fit.
INTAKE AND EXHAUST
MANIFOLDS
❖
D isassem b le (F ig u re 4)
1. Bolts (39) and washers (40).
2. Nuts (32).
3. Intake m anifold (31) and exhaust manifold (37).
4. Gasket (36).
1 3 1
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Old pieces of gasket from the gasket surfaces.
Manifolds for cracks, broken flanges, etc.
Gasket surfaces for heavy scratches.
M anifold heat control valve (if used). The heat
c o n tro l valve is in th e e xha u st m a n ifo ld . The
therm ostatic spring and anti-rattle spring must be in
place and in good condition. The shaft should turn
freely when w eight is moved and the spring should
return the shaft to its original position.
m
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Manifold distortion. Lay a straight edge along the
full length of the exhaust port faces and measure
any gaps between the straight edge and the port
faces. If at any point a gap of 0.80 mm (0.030-inch)
or more exists, it is likely that the manifold has
distorted to a point where it will not seal properly. If a
good exhaust seal is to be expected, the exhaust
manifold must be replaced.