TM 5-3810-300-24&P-3
1.2.2 EXHAUST VALVES
moment the exhaust valve starts to open. The
minimum pressure required to start to open the
exhaust valve must not be less than 20 pounds
(2 valve spring design).
11. Install the cylinder head (see "Pre-Installation
Inspection" and "Install Cylinder Head" in Section
1.2). Adjust the exhaust valve bridges.
Exhaust Valve Bridge Adjustment
Fig. 19. Former and Current Exhaust Valve Spring Caps
On an engine equipped with a four valve cylinder head,
6. Install the valve springs, and valve spring caps.
the exhaust valve bridge assembly is adjusted and the
adjustment screw is locked securely after the cylinder
NOTE: The current valve spring cap
head is installed on the engine. Until wear occurs, or the
has a ridge for identification purposes on
cylinder head is reconditioned, no further adjustment is
required on the valve bridge. A complete valve bridge
adjustment is performed as follows:
one of the rocker shaft bolt holes in the cylinder
1. Place the valve bridge in a vise or holding fixture
J 21772 and loosen the lock nut on the bridge
adjusting screw.
8. Apply pressure to the free end of the too; to
compress the valve spring and install the two-
CAUTION: Loosening or tightening the
piece tapered valve lock. Exercise care to avoid
lock nut with the bridge in place may
scoring the valve stem with the valve cap when
result in a bent bridge guide or bent rear
compressing the spring.
valve stem.
NOTE: Compress the valve spring only
enough to permit installation of the valve
locks. Compressing the spring too far
may result in damage to the valve guide
oil seal if used.
9. Release the tool and install the valve locks on
the remaining exhaust valves in the same
manner.
NOTE: After the valves have been
installed, make sure that none of the
valve heads protrude more than the
limits shown in Fig. 16 above the surface
of the cylinder head when the valves are
fully closed.
10. With the exhaust valves installed in the cylinder
head, refer to Fig. 20 and, using spring checking
Fig. 20. Checking Pressure Required to Open
gage WRE 500-60, note the gage reading the
the Exhaust Valve in Cylinder Head
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