ENGINE AND PERIPHERALS
Overhauling the engine
10
10-100
Value of the piston-cylinder head clearances
Form this dimension (piston - valve), subtract the valve
clearance value measured earlier; the result (piston -
cylinder head clearance) should be more than 0.6 mm.
Example of completed measurement, cylinder
head removed from the engine:
1) Piston protrusion (after turning the crankshaft
clockwise at the timing end)
(Measurement A):
– cylinder n˚ 1, A = 1.05 mm
– cylinder n˚ 2, A = 1.04 mm
– cylinder n˚ 3, A = 1.05 mm
– cylinder n˚ 4, A = 1.07 mm
In this case use measurement A = 1.07 mm for
cylinder 4.
This measurement being greater than 1.04 mm, fit a
cylinder head gasket 1.8 mm thick.
2) Valve clearance (measurement B)
On the inlet and exhaust valves of the 4
th
cylinder:
Inlet: B = 0.92 mm
Exhaust: B = 0.87 mm
(The clearance is between 0.80 and 1.15 mm).
In this case, use the measurement B = 0.87 mm for
the exhaust valve, it being the smaller.
Cylinder head fitted on the engine (with the cylinder
head gasket and tightened to torque):
3) Valve - piston clearance (measurement C)
On the exhaust valve stem of the 4 th cylinder
(reminder: piston at top dead centre):
C = 1.57 mm
which gives the PISTON/CYLINDER HEAD
CLEARANCE:
D = C - B = 1.57 - 0.87 = 0.7 mm
(This clearance is thus greater than 0.6 mm).
Refit:
– the camshaft (16),
– the rocker arm rail (17),
– the fuel return rail to the tank, fitted with new copper
seals.
83367S
ProCarManuals.com
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