Vaz 21213, Руководство по ремонту, Страница: 29 / 222

Disconnect the leads from the spark plugs and coolant tem-
perature sender, from carburettor idle switch and fuel cutoff sole-
noid.
Disconnect the choke cable; disconnect the throttle linkage
from the intermediate lever on the valve cover.
Loosen the clips and disconnect the carburettor supply /
return fuel hoses. Secure the hoses in a manner to exclude pos-
sible fuel leaks. Detach the vacuum hose from the carburettor.
Disconnect the hoses from the intake pipe, from the outlet
pipe of the cooling water jacket and from coolant delivery pipe to
the heater. Remove the EGR valve.
Disconnect the starter motor shield from the exhaust mani-
fold, downpipe and detach the bracket securing the coolant pipe
(heater return line).
Remove the valve cover complete with the gasket and fuel
piping securing bracket.
Turn the crankshaft to align the camshaft sprocket TDC mark
against the bearing housing mark (Fig.2-22).
Unbolt the camshaft sprocket. Slacken the chain tensioner
cap nut, release the tensioner rod and fix it in position with the
cap nut. Remove the camshaft sprocket.
Undo the bolts securing the cylinder head to the cylinder
block and remove the cylinder head complete with the gasket.
Refitting of the cylinder head is the reverse order of removal,
refer to the procedure described in section «Engine reassembly».
Never re-use the gasket between the cylinder head and cylinder
block, always replace it with a new one.
While refitting the cylinder head, adjust the timing chain ten-
sion and valve clearances. Having refitted the cylinder head,
adjust the carburettor linkage and ignition timing.
Cylinder head - dismantling and reassembly
Dismantling. When only a single part is required to be
replaced, there is no need to completely dismantle the cylinder
head; instead, remove only what is necessary.
Position the cylinder head on the stand, disconnect the hose
from the hot air intake, undo the nuts and remove the carburettor
complete with the gasket; next withdraw the inlet and exhaust
manifolds (the hot air intake is withdrawn at the same time).
Remove the water jacket return pipe and coolant-to-heater
return pipe. Unscrew the spark plugs and coolant temperature
sender.
Undo the securing nuts and remove the bearing housing
complete with the camshaft. Undo the nuts holding the thrust
flange to the bearing housing. Remove the flange and lift out the
camshaft from the bearing housing.
Release springs 12 and remove valve rocker levers 11
(Fig.2-43). Remove the rocker lever springs.
Slacken lock nuts 14, undo adjuster bolts 13 and bushes 15.
Position tool Ä.60311/R, as shown in Fig.2-44, compress the
valve springs and release the collets. A stationary tool
02.7823.9505 can be used instead of tool Ä.60311/R.
Remove the valve springs together with lower and upper
seats. Turn the cylinder head over and remove the valves from
the underneath. Take off the outer caps from the valve guides.
Reassembly. Reassemble the cylinder head in the reverse
order. Before assembly begins, always oil the outer caps and
valves with engine oil.
Before refitting the camshaft bearing housing, check the cen-
tering pins are in the position (Fin.2-21). Tighten the bearing
housing securing nuts in the sequence as shown in Fig.2-23.
Ensure the centering pins are positioned in the bearing housing
recesses without sheering.
The valve clearances are adjusted only after the cylinder
head has been refitted to the engine.
Inspection and overhaul
Cylinder head. Thoroughly wash the cylinder head and
clean the oilways. Scrape away all carbon from the combustion
chambers and from the exhaust valve ports with a wire brush.
Examine the cylinder head. Look to see there is no cracking
in the cylinder head. Check the cylinder head for leakage when
suspicious as to possible oil contamination with coolant.
To do this, plug the cooling water jacket holes (using plugs
from tool A.60334, Fig.2-45), then pump water into the cylinder
head water jacket at 0.5 åP‡ (5 kgf/Òm
2
). No water leak should
be evident within 2 minutes.
The cylinder head tightness can be checked with compressed
air. Plug the water jacket holes (using the same plugs from tool
Ä.60334), immerse the cylinder head into the bath with water of
60-80°C for 5 minutes. Next pump the compressed air into the
cylinder head at 0.15-0.2 åPa (1.5-2 kgf/Òm
2
). No air bubbles
must be seen from the cylinder head within 1-1.5 minutes.
Valve seats.
The valve seat chamfer shape is shown in
Fig.2-46 and Fig.2-47. Check the working chamfers of the valve
seats (valve contact area) for pitting, corrosion or deterioration.
Minor irregularities of the seats must be recut. Remove as little
metal as possible. Both manual and machine grinding is permit-
ted. Valve regrinding is carried out as follows.
Position the cylinder head on a mounting base. Insert cen-
tering tool A.94059 in the valve guide and clean the seat cham-
fers from carbon using tools Ä.94031 and Ä.94092 for the
exhaust valves and Ä.94003 and Ä.94101 for the inlet valves.
Use spindle Ä.94058 and centering tool Ä.94059. The centering
tools differ in diameters, use tool Ä.94059/1 for the inlet valve
guides and Ä.94059/2 for the exhaust valve guides.
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