Hyundai HDF 50-7S, Руководство по обслуживанию

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INSPECTION AND REPAIR OF BASIC ENGINE
6-7
1.8 Lapping valve and valve seat
Always lap the valve against the valve seat after refacing the
valve seat or after replacing the valve.
(1)
Apply a thin coat of lapping compound evenly to the
valve face.
Note: (a) Do not allow the compound to adhere on the
valve stem.
(b) Compound spreads more evenly if it is mixed
with a small amount of engine oil.
(c) Use medium-grain compound (120 to 150 mesh)
for initial lapping, then use fine-grain compound
(200 mesh or finer) for finishing.
(2)
Use a valve lapper for lapping. Strike the valve against
the valve seat while rotating the valve little by little.
(3)
Wash off the compound using diesel fuel.
(4)
Coat the contact surface of the valve with engine oil,
then lap the valve again.
(5)
Check valve-to-seat contact.
Coating valve with lapping
Lapping valve and valve seat
1.9 Measuring perpendicularity and free length
of valve spring
Measure the perpendicularity and free length of the valve
spring. If the measured free length and/or perpendicularity
exceed the limit, replace the valve spring with a new one. If
the measured set length and/or set load deviate from the
standard, replace the valve spring with a new one.
Squareness and free length of spring
Compound
Valve lapper
Item Standard Limit
Free length
48.85 mm
[1.9232 in.]
47.60 mm
[1.8740 in.]
Perpendicu-
larity
A = 1.5° or less
B = 1.3 mm
[0.051 in.]
or less
Lf = 48.85 mm
[1.9232 in.]
B = 1.5 mm [0.059
in.]
at the end
Set length/set
load
43 mm [1.69 in.]/
176 to 196 N
{18 to 20 kgf}
[39 to 44 lbf]
43 mm [1.69 in.]/
147 N
{15 kgf}
[33 lbf]
A
B
Lf
Free length
Spring perpendicularity (gap)
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