Toyota 4A-F, Руководство по ремонту

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ENGINE MECHANICAL Description {4A·GEI
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
5
bearings
SPIICitied by lhe ;n�e of the crllrlkcase . Thllse
Marings II" mllde of IIluminum 1I110y.
The crllnkshllft il intflgraled with
a
w�ghts
whM::h lire CUI along with II for balancing. Oil holes
are buill into the center of the crllflksNift for sup­
pfying oil to Ihll connecting ,ocIs. pistonllnd olhllr
components.
This engine's ignition order i, 1-3·4-2. The
eyhnder head 's I'I\lIde of aluminum alloy. with.
CIOU flow type intake and e"haust liyout and with
pent roof type combustion chamtMIrs. The 8pa,k
plugs are located in the center of the combustion
chambers.
The intake manifold hn a independent long
ports end utilizes the inertial supercharging effKt
to improve engine IOfQue at low and medium
speeds .
e"haust and intake valves lire equipped with
flflgular pilch springs made of oil tempered silicon
chrome steel wire which an! capable of following
\tie valves even al high engine .peeds.
Both the uhlluS! side cam shalt lind the in�ke
"de cam shIft sre driven by 8 single liming bell
The cam joum81 is supported 8t
5
pl8ees between
the valve lifhlrs of each cylinder lind on the front
end
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
means of an outer shim type system. in which
valve adjosling shims Ilrll located above the vslve
itterl. This permits replacement of the shims
Wllhout removel of the camshafts.
The resin timing belt cover i, made in 3 piec:es.
A service hole is provided in the No.2 belt coyII'"
lor adjo$llng the timing belt tension.
Pistons are made of higilly temperature-res is­
IlInt aluminum alloy. and II depression is built into
the piston head to prevent interference with
�a l v 8$ .
Piston pins are the lull-floating type. with the
gins f�stenecl to n�u- the piston boss nor the
,oonecling rods. Instead. $lIap rings lire filled on
ooth ends
01 tho pins. preventing the pins Irom
filling out.
The No . I compression ring Is made of steel and
the No.2 comprenion ring i. made of cast Won.
The oil ring is made of a combination of Iteel and
ullinless stee!. The DUtil" diameter of each piston
nl"l(l 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 p i stoo . 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.
TIM! cylinder block is made of CltSt iron.
It
has 4
cylinder, which are approJO.imalely 2 times the
length of the piston s tr o k e . The top of the cylin·
ders is closed off by the cylinder head and the
lower end of the cylinders becomes lhe crankcaSll.
in which the cranksheft is i nstalled . In addition. the
c'{linder block contains e weIer jacket. through
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 1llIIllheet. 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. " stopped suddenly lind
Ihus Ihiltil"l(l the oil away from the oil pump suc­
tion pipe.