Weifang 495 - Page 58

1-.- Thermostat; 2- Therm, ,stat housing; 3- "0" ring, seal; 4-,. ,-: TheTmostat
gasket; 5-- Valve collet ,halyes, 6-~"-- Valve spring seat; 7-Rocker arm~~aft ,bracket
sub--assenlbly;8--Valve sprin:; lower seat;9-Cylinder head cover sub-assem-
• '; , "i
bly ; 10- Lifting bracket; 11- Cylinder head rear cover; 12- Cylinder head front
,and rearcovar gasket; 13--Cylin.der head; 14-Valve guide ;'15--'SwirlcoIrtbustion
chamber insert; IS-Intake valve seat insert;17-Exhaustvalveseatinse,rt;:la---ln-
jector clamp; 19- Intake manifold gasket; 20-- Cylinder head, cov.er gasket;~.l~_- -,
Outer valve spring; 22- Inner valve spring; 23- Intake valve; 24- Roc~er arm
, , " :', " i
shaft bracket stud; 25- Exhaust valve; 26--- Cylinder head front cover; 27-"- T'em-
perature gauge a~apter; 28--'Exhaust manifold gasket;
'Cylinder head is an one piece casting <Fig.; 2 ).Theind"ep'en-
dent intake and exhaust manifolds are installed on 'each side ,of·-the
cylinder head respectively. A thermostat is installed," o-Ii,the' cylin-
der head front cover to regulate the outlet wa'ter ternperatur·e".The
insert, with a slant throat of kidn~y shape cross ---: s"ection and a
small cOIlical hole inside, is pressed into the' bottom of the swifl
chamber. The small conical hole should be aligned ;with the' nozzle
center line in installation of the insert so ,as to mak:e the' 'engine
easy to start. The valve guides and seats, made by powder,'tnetal-
lurgy and of alloy cast iron respectively to increase theirwe'a.r·;-·re-
sistance, are all pressed into the cylinder head with interference
fit.
Intake and exhaust valves are made of alloy steel and heatre-
sisted alloysteel respectively. The head of the intak~ valv,e is bigger
than that of the exhaust valve. There is a strict'dimellsional re-
..
quiremeIlt for the distance from the valve head to the cylinder head
bottom surface in order to keep the engine compresslontatio ex-
actly and to avoid the valve impact against the piston. The valve is
fitted with inner and outer valve springs and positioned by the up-
per spring seat and the collet halves.
The rocker arm mechanism.is housed in the cylinder head cov-
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