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ENGINE DIVISION SERVICE MANUAL
TM 5-4210-230-14&P-1
ENGINE
b.
Small amount of air in oil which can only be helped
by eliminating the aeration.
3.
Intermittent noise is usually the result of:
a.
Metal chips or dirt. Occasionally such material
becomes lodged between the check valve and seat.
Cleaning will correct this condition.
b.
Slight plunger sticking caused by dirt or varnish-like
substances,
which
necessitates
cleaning
and
eliminating the source of varnish.
B.
When engine is overhauled.
Lifters will need to be removed and normal varnish
deposits cleaned off whenever a change has been
made that will increase the distance from the cam to
the valve tip. This change may cause the plunger to
be forced into a varnish deposit accumulated above
the original travel of the plunger. Since the plunger
previously had not been required to operate in this
position, the lifter must be removed and cleaned of
all varnish deposits so the plunger can move freely.
The following will cause increased valve train length:
1.
Grinding valve tips.
2.
Valve train parts not put back in their respective
locations.
3.
Installing new parts.
Even when doing a valve grind job, it may not be
necessary to disturb the lifters. However, it may be
found occasionally that worn valve tips will need to
be ground to give a smooth surface. In this case the
length from cam to valve tip would be increased,
which necessitates cleaning the lifter as mentioned
above.
As a general rule, hydraulic lifters should be left
alone when they are functioning satisfactorily and the
valve train or gear remains reasonably quiet. The
hydraulic lifter is a fairly simple positive action
device which will continue to deliver trouble-free
service
under
all
normal
engine
operating
conditions. The major cause of hydraulic lifter
problems, where any exist are usually due to grit, dirt
or metal chips carried to the lifter with the engine oil.
To minimize lifter contamination, a special box or
container should be used to store the lifters when
they are first removed from the engine or after they
have been cleaned and tested. Keep the lifters in this
container until ready for installation in the engine.
The container should be numbered to assure return
of the lifters to their original location in the engine.
NOTE:
Even
when
the
lifters
are
working
correctly, there are other engine noises
which are often "blamed" on lifters but can
susally be identified. These may be
caused by: valve stem guide clearance,
worn timing gears, piston slap, lifter body
clearance, worn lifter face or cams, loose
main or rod bearings, worn rocker arms,
ignition knock, worn valve tips or tight
rocker arms.
III. Lifter Disassembly
Before disassembling lifters it may be necessary to
remove a portion of the oil from the lifter body. This can be
accomplished by turning the tappet upside down and letting it
drain for a few minutes. Then with the end of a push rod,
compress the plunger and remove the snap ring located on
the inside top of the assembly.
Caution should be used in order that the snap ring
does not "pop out" and become lost. Removal of this snap
ring should allow the separate socket to be readily removed.
By shaking the assembly gently, the plunger should also
come out unless it is held in place by carbon and varnish
deposits. If this is the case, some force will be required to
remove the plunger from the body. It may be necessary to
hold the assembly upside down and bump the open end
gently against some resilient surface (masonite, etc.). Care
should be taken so the plunger or body will not be damaged.
CGES-210 Page 46
PRINTED IN UNITED STATES OF AMERICA
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