TM 5-3895-359-14&P
Fig. 4. Testing Exhaust Valve Spring using Tool J
22738-02
Inspection
Fig. 5. Cleaning Valve Guide
Clean the springs with fuel oil, dry them with
the valves or install new valves. If the valve heads are
compressed air and inspect them. Replace a pitted or
warped, replace the valves.
fractured spring.
If there is evidence of engine oil running down the
Use spring tester J 22738-02 to check the spring load
exhaust valve stem into the exhaust chamber. Creating
a high oil consumption condition because of excessive
valve spring when a load of less than 25 pounds (111 N)
idling and resultant low engine exhaust back pressure,
will compress it to 2.20 " (installed length).
replace the valve guide oil seals.
Inspect the valve spring seats and caps for wear.
If
Clean the inside diameter of the valve guides with brush
worn, replace with new parts.
J 5437 (Fig. 5). This brush will remove all gum or
carbon deposits from the valve guides, including the
Examine the contact surfaces of the exhaust valve
spiral grooves.
bridge guides, bridges and adjusting screws for wear or
galling. Replace excessively worn parts.
Inspect the valve guides for fractures, chipping, scoring
or excessive wear. Measure the valve guide inside
Carbon on the face of a valve could indicate blow-by
diameter with a pin gage or inside micrometer and
due to a faulty seat. Black carbon deposits extending
record the readings. After inspecting and cleaning the
from the valve seats to the valve guides may result from
exhaust valves, measure the outside diameter of the
cold operation due to light loads or the use of too heavy
valve stems with a micrometer and record the readings.
a grade of fuel. Rusty brown valve heads with carbon
Compare the readings to obtain the valve-to-guide
deposits forming narrow collars near the valve guides is
clearance. If the clearance exceeds .006" replace the
evidence of high operating temperatures.
High
valve guides.
operating temperatures are normally due to overloads,
inadequate cooling or improper timing which results in
Replace Exhaust Valve Guide
carbonization of the lubricating oil.
Remove an exhaust valve guide as follows:
Clean the carbon from the valve stems and wash the
valves with fuel oil. The valve stems must be free from
1. Remove and discard the valve guide oil seal, if used.
scratches or scuff marks and the valve faces must be
free from ridges, cracks or pitting. If necessary, reface
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