Chpter IV Mechanical System
Great Wall Baoding Internal Combustion Engine
Manufacturing Company Limited
155
Fig. 4-3-20 Checking the valve tightness
Fig. 4-3-21 Installing the valve oil seal
4.4 Checking the valve tightness
(1) Draw 8-12 lines evenly on the valve head taper face
in the circumferential direction with a pencil. See Fig.
4-3-20.Reinstall the valve, pat the valve seat for several
times (
Attention:
Do not turn the valve). The valve
tightness is considered to be good if all the pencil marks
break at the ring part.
(2) Or reinstall the valve, spring etc., then inject some
kerosene through intake/exhaust passage. The
tightness is considered to be good if there is no leakage
for 3-5 min.
Reassembly
Reassembling the valve oil seal
⑤
(1) Apply a little lubricating oil to the sealing surface of
valve oil seal.
Mobil API CI-4 lubricating oil
(2) Press the valve oil seal into the valve guide head
with a special tool.
Valve oil seal installer: 5-8840-2033-0.
(3) Conduct pressure leakage test on the valve oil seal,
and the specification is as below: the air leaking amount
should be less than 20 mL/min under 50~70 kPa.
Attention:
Do not reuse the removed valve oil
seal. Replace it with a new one.
Fig. 4-3-22 Installing the valve, spring and
lock clamp
Reassembling valve
④
(1) Apply engine oil outside the valve stem and inside
the hole wall of valve guide before installing the valve.
Mobil API CI-4 lubricating oil
(2) There is a requirement for the matching between the
valves with marks on heads and the valve seats after
facing up, so it is required to plug the valve into the right
place, and no misplacement is allowed. Install the valve
into the valve guide.
The valve in the valve guide hole should be able to
move flexibly without any seizure after the installation.
Reassembling the valve spring
③
(1) Install the valve spring onto the valve spring gasket.
(2) The valve spring should contact with the bottom
surface of valve spring seat allocating column, and it is
not allowed for the spring to be stuck to the surface of
Valve oil seal
Intake valve
Exhaust
valve
Valve lock clamp
Valve spring seat
Valve spring
