Toyota 4A-F Repair Manual page 6

The 4A-GE engi('lfl is en in-�ne 4-cylinder engine
with the cylinders numbeTed '.2·3-4 from the
tront The crankshaft is supporloc;l by
SPIICitied by lhe ;n�e of the
Marings II" mllde of IIluminum 1I110y.
are
The crllnkshllft il intflgraled with
whM:: h lire CUI along with II for balancing. Oil holes
buill into the center of the crllflksNift for sup­
pfying oil to Ihll connecting ,ocIs. pistonllnd olhllr
components.
CIOU
This engine's ignition order i, 1-3·4-2. The
eyhnder head 's I'I\lIde of aluminum alloy. with.
flow type intake and e"haust liyout and with
pent roof type combustion chamtMIrs. The 8pa,k
plugs are located in the center o f the combustion
chambers.
to
The intake manifold hn
ports end utilizes the inertial supercharging effKt
improve engine IOfQue at low and medium
speeds.
e"haust and intake valves lire equipped with
\tie
flflgular pilch springs made of oil tempered silicon
chrome steel wire which an! capable of following
valves even al high engine .peeds.
The
Both the uhlluS! side cam shalt lind the in�ke
the
"de cam shIft sre driven by 8 single liming bell
end
cam joum81 is supported 8t
valve lifhlrs of each cylinder lind on the front
ot till cylinder h88d. lubricltion of the cam
ioumal lind cam is accomplished by oil blling sup­
plied through the oilll" port in the cantil" of the
C3mshlit.
Adjustment of Ihe valvI clearaOCI Is done by
itterl.
means of an outer shim type system. in which
valve adjosling shims
This permits replacement o f the shims
A
Wllhout removel o f the camshafts.
The resin timing belt cover i, made in 3 piec:es.
service hole is provided in the No.2 belt coyII'"
lor adjo$llng the timing belt tension.
Pistons are made of higilly temperature-res is­
IlInt aluminum alloy. and
the piston head to
�alv8$.
Piston pins are the lull-floati n g type. with the
gins f�stenecl to n�u- the piston boss nor the
,oonecling rods. Instead. $lIap rings lire filled on
I
ooth ends 01 tho pins. preventing the pins Irom
filling out.
The No. compression ring Is made o f steel and
the No.2 comprenion ring i. made of cast Won.
nl"l(l
The oil ring is made of a combination of Iteel and
ullinless stee!. The DUtil" diameter of each piston
is slightly lergar than the diameter of the
poston and the fleJO.ibility of the rings allows them
to hug Ihe cylinder walls when they ere mounted
on the pistoo. Compntssion rings No.1 end No.2
wo.k 10 prevent the teakage of gas from the
cylinder end Ih. oil ring works to scrape oil off the
eyfinder wells to prevent it from entering the com­
i)oltion chamber.
ENGINE MECHANICAL
5 bearings
a
crllrlkcase.
w�ghts
a
independent long
5 pl8ees between
Ilrll
located above the vslve
II
depression is built into
prevent interference
Description {4A·GEI
TIM! cylinder block is made of CltSt iron.
cylinder, which are approJO.imalely 2 times the
length of the piston
ders is closed off by the cylinder head and the
Thllse
lower end of the cylinders becomes lhe crankcaSll.
in which the cranksheft is
c'{linder block contains
which coolant Is pumped to cool lhe cyfinders
The oil pan Is bolted onlo the bottom of the
cylinder block. The oil pen is lin oil reservoir mlKla
of pressed 1 llII l lheet. A dividing pllte is included
Inside the oil pan to keep .officient oif in the bot­
tom of the pan even when the vehicle is tilted. This
dividing plate also prevlnlS the oil from making
waves when the vehicl. "
Ihus Ihiltil"l(l the oil away from the oil pump suc­
tion pipe.
with
stroke. The top of the cylin·
e
installed. In addition. the
weIer jacket. through
stopped suddenly lind
It
has 4