engine top end construction Flashcards
define bare cylinder head
its a complex metal casting with all of its parts removed
what is a bare cylinder head normally made out of
cast iron or alluminum
the construction of a clyinder head varies with engine —- and —-
deisgn and type
an —– valve guide is part of the cylinder head casting
integral
an —- valve guide is a seperate sleeve forced into a hole machined in the cylinder head
pressed in
name two types of valve seats
pressed in and integral
define valve seat angle
its an angle formed by the face of the seat
the most common valve seat angles are
45 degrees and 30 degrees
an —- angle is a 1/2-1 degree difference between the valve seat face angle and the angle of the valve face
interference
a diseal prechamber cup is pressed into the cylinder head and encloses the tips of the —- and —–
injector and glow plug
what is the function of an engines valve train
it controls the opening and closing of the cylinder head ports
automotive engines commonly use —- or —- valves
poppet and mushroom valves
define valve face angle
its the angle formed between the valve face and valve head
—- filled hollow stem valves are used when extra valve cooling action is needed
sodium
a stellite valve is often used in engines designed to burn —— fuel
unleaded
an —- valve seal is shaped like a cup and can be made of neoprene rubber or plastic
umbrella
an —- valve seal is a small round seal that fits into and extra groove cut in the valve stem
o-ring
a valve spring —– is normally used with an o-ring type of seal
shield
define valve spring tension
the stiffness of a valvenspring measured in pounds or kilograms
valve spring —- is the length of th valve srping when removed from the engine
length
define valve spring open length
its the springs length when installed on the engine with valve fully open
valve spring —- is the length of the valve spring when instaled on the engine with the valve closed
closed
valve — occurs when the valve fails to close entirely at high rpms because the spring is too weak
float
a valve spring —- is a very thin, accuratly machined washer used to increase spring tension
shim
what is the function of valve retainers and keepers
they lock the valve spring onto the valve
a valve spring — is cup shaped washer installed between the cylinder head and the bottom of the valve spring
seat
explain the purpose of valve rotators
turns the valve to prevent carbon buildup and hot spots in the valve face
a valve —- helps prevent stem and rocker arm wear
stem cap
what is the function of an engines camshaft
controls when the valves open and close
cam lobe can be used to control —-
d- all the above
cam shaft —- is the disntance the valves open
lift
camshaft —- determines how long the valve stays open
duration
define valve timing
refers to valve opening and closing in relation to the position of the pistons in the cylinders
— is the time when both the intake and exhaust valves in the same cylinder are open
valve overlap
describe the purpose of a camshaft thrust plate
its used to limit camshaft end play
the camshaft journals ride in the cam —
bearings
explain the term cam housing
its a casting that bolts to the top of the cylinder head to hhold the engine camshaft
a cam cover serves the same purpose as a — cover on an overhead valve engine
valve rocker cover
valve — ride on the camshaft lobes and transfer motion to the other parts of the valve train
lifters
— lifters are common because they operate quietly by maintaining zero valve clearance
hydraulic valve
— lifters are not self adjusting and require periodic adjustment
mechanical
a roller lifter can be either mechanical or —
hydralic
how is valve ckearance normally adjusted on engines equipped with OHC followers
either an adjusting screw in the follower or shims of different thicknesses can be used to adjust valve clearance
—- are used in cam in block engines to transfer motion from the lifters to the rocker arms
push rods
describe the function of rocker arms
they transfer valve train motion to the valve stem tips
rocker arms are usually made of either — or —-
cast iron or steel
—– rocker arms are used to change the valve train clearnace
adjustable
one method of acheving variable valve timing uses an — that can rotate on the camshaft
camshaft gear
another method of achieveing variable valve timing relies on eletro-hydrauliclly operated — and two different camshaft profiles for each valve
rocker arms
an intake maifold holds the —- and has passages (runners) going to each cylinder head port
throttle body
—- are internal passages formed in the intake manifold to carry either the air fuel mixture or air to the cylinder head ports
manifold runners
define flame arrester
it prevents backfire damage to the air filter
an — system has two sets of intake runners controlled by butterfly valves to aid engine efficiently and performance
variable induction
describe the funtion of an exhaust manifold
routes burned exhaust gases from the cylinder head exhaust port to the echaust pipe
a few high performance or sports car engines use lightweight , free flowing steel tubing exhaust manifolds called —-
headers
