What material is commonly used to provide a
wearing surface in a liquid-cooled engine for the
pistons to ride against?
What are the two types of cylinder sleeves?
What are the two types of core hole plugs used in
an internal combustion engine?
What is the basic foundation of all air-cooled
A properly made exhaust manifold results in
what type of action to help an engine get rid of
In an exhaust-heated intake manifold, gases
diverted to the manifold are controlled by what
What two basic types of oil seals are currently
being used on engines?
What ate the structural components of a piston?
What are the three types of piston pin
What three functions do piston rings serve?
What part is the backbone of an internal
The valve actuating mechanism is made up of
what engine parts?
What are the three basic shapes of a poppet-type
What type of valve is preferred in a vehicle using
What are the two basic types of valve seals?
What three characteristics of a valve spring
should you check?
ENGINE ADJUSTMENT AND
LEARNING OBJECTIVE: Describe The
techniques used in adjusting engine valves.
Recognize basic engine testing procedures and
Proper and uniform valve adjustments are required
for a smooth running engine. Unless the clearance
between the valve stems and rocker arms or valve lifters
is adjusted according to the manufacturers
specifications, a valve does not open and close at the
proper time, and engine performance is affected.
In most shops, the Navy provides accurate and
dependable testing equipment. But having the testing
equipment in the shop is NOT enough. The supervisor
and crew must know how to use this equipment properly
since it provides the quickest and surest means of
determining what is wrong and where the fault lies.
Valve adjustment, also called tappet clearance
adjustment or rocker adjustment, is critical to the
performance and service life of an engine. If the valve
train is too loose (too much clearance), it can cause
valve train noise (tapping or clattering noise from the
rocker striking the valve stems). This can increase part
wear and cause part breakage. Valves that are adjusted
too tight (inadequate clearance) may be held open or
may not close completely. This can allow combustion
heat to blow over and burn the valve.
When reassembling an engine after reconditioning
the valves, make sure the adjusting screws are backed
off before rotating the engine. A valve that is too tight
could strike the piston and damage either the piston or
the valve, or both. Adjust the valve according to
manufacturers specifications, following the
On any engine, after valve adjustments have been
made, be sure that the adjustment locks are tight and that
the valve mechanism covers and gaskets are in place
and fastened securely to prevent oil leaks.
Most overhead valves are adjusted "HOT"; that is,
valve clearance recommendations are given for an
engine at operating temperature. Before valve
adjustments can be made properly, the engine must be
run and brought up to normal operating temperature.
To adjust a valve, remove the valve cover and
measure the clearance between the valve stem and the
rocker arm. Loosen the locknut and turn the adjusting