Intake And Exhaust Manifold; Camshaft - GMC 1989 Light Duty Truck Repair Manual

6A1-16 2.5 LITER L4 ENGINE
108. C a m s h a ft
Figure 25— Measuring Camshaft Journal Runout
INTAKE AND EXHAUST
MANIFOLDS
Clean
• Old pieces of gasket from the gasket surfaces.
Inspect
Manifolds for cracks, broken flanges, etc.
Gasket surfaces for heavy scratches.

CAMSHAFT

Inspect (Figure 5)
Camshaft lobes and journals for scratches, pitting,
scoring, and wear.
Timing gear for damaged or missing teeth.
M easure (Figures 25 through 27)
Tool Required:
J 7872 Dial Indicator (or equivalent)
Cam shaft runout. Mount the cam shaft between
ce n te rs or in V-blocks. U sing tool J 7872 (or
e q u iva le n t), ch e ck the in te rm e d ia te ca m sh a ft
Figure 2 6 — C hecking the C am shaft Journals
F-01998
Figure 27— Measuring Camshaft Thrust Plate
journals. If runout exceeds 0.020-inch, the camshaft
is excessively bent and should be replaced, along
with the camshaft bearings.
Camshaft journal out of round. Use a micrometer. If
the journals are more than 0.001-inch out of round,
replace the camshaft.
Camshaft journal diameter. Use a micrometer. The
proper diameter is 1.869-inch.
Thrust plate (105) to camshaft (108) clearance. This
clearance governs camshaft end play. Use a feeler
gage. The proper clea ra n ce is 0.0015-inch to
0.0050-inch. If the clearance is less than 0.0015-inch
replace the spacer ring (106). If the clearance is
more than 0.0050-inch, replace the thrust plate
(105).
*
D isassem ble (Figure 28)
1. Gear (104) from the camshaft.
• Place the camshaft gear in a press. Support
Figure 2 8 — R em oving the C am shaft G ear
Clearance (Camshaft End Play)
the camshaft gear. DO NOT support the thrust
plate.