TM-9-2320-280-34

TRUCK, UTILITY: M998 SERIES

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE

JANUARY 1996
TM-9-2320-280-34

  TM-9-2320-280-34 - Page 80 of 1258

TM 9-2320-280-34
3-10.
TIMING CHAIN COVER, TIMING CHAIN, AND DRIVE SPROCKETS MAINTENANCE
This task covers:
a.
Removal
c.
Installation
b.
Inspection
INITIAL SETUP:
Tools
Manual References
General mechanic's tool kit:
TM 9-2815-237-34P
automotive (Appendix G, Item 1)
Equipment Condition
Materials/Parts
Torsional damper removed (para.
3-7).
Gasket (Appendix E, Item 15)
Water pump and adapter plate removed
Three woodruff keys (Appendix E, Item 214)
(para.
5-4).
Flange sealant gasket set
(Appendix B, Item 45)
Maintenance Level
Lubricating oil (Appendix B, Item 31)
Direct support
a.
Removal
NOTE
When measuring timing chain deflection, slack should be removed
from one side before measurement is taken on opposite side.
In some cases, flanged head fasteners may be present instead
of standard fasteners and washers.
In all cases, washers should
be used when replacing a flanged head fastener with a standard
fastener.
Perform step 1 for M997, M997A1, and M997A2 ambulance
vehicles only.
1.
Remove nut (5) and screw (7) from timing chain cover (6).
2.
Remove three capscrews (1) and driven gear (2) from injection pump (9).
3.
Remove two capscrews (18), nut (3), and baffle (4) from timing chain cover (6).
4.
Remove three nuts (11) and washers (10) from injection pump (9) and timing chain cover (6).
5.
Remove four capscrews (13) from timing chain cover (6) and oil pan (14).
6.
Remove five capscrews (16), four washers (15), timing chain cover (6), and gasket (8) from cylinder
block (12).
Discard gasket (8).
7.
Using dial indicator, check timing chain (23) deflection midway between camshaft sprocket (22) and
crankshaft sprocket (29).
Total deflection must not exceed 0.810 in.
(20.6 mm).
If deflection exceeds
specification, timing chain (23) must be replaced.
8.
Using dial indicator, check camshaft end play.
Camshaft end play must not be more than 0.012 in.
(0.3 mm).
If end play exceeds specification, camshaft sprocket (22) and thrust plate (26) must be
inspected for wear after removal.
9.
Remove capscrew (19), washer (20), pump drive gear (21), and camshaft sprocket (22) from camshaft
(24).
10.
Remove crankshaft sprocket (29), camshaft sprocket (22), and timing chain (23) as an assembly.
NOTE
Cover oil pan opening to prevent woodruff keys from falling into oil pan.
11.
Remove two woodruff keys (27) from crankshaft (28) and woodruff key (25) from camshaft (24).
Discard woodruff keys (27) and (25).
3-20


Back to Top