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1)
While disassembling the cylinder head, observe
the details of the valves and all valve train components (including
tappets, push rods and rocker arms) in order to realize a
diagnosis on the problem the engine could have had. |
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| 2)
In case of no parts replacement keep together the elements
of each group of elements in order to avoid mixing parts
of different groups. |
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3)
Wash carefully the cylinder head and the elements of the
engine using a hot biodegradable product under pressure. |
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| 4)
The mounting of the guides must be perpendicular and
centered in order to avoid the inner diameter to close.
Liquid Nitrogen may be used to cool down the guides before
installing them. |
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5)
We suggest do not mechanize the guide on the inside. If it
is required, after mounting it, realize the operation
using sharpened tools and avoiding manual devices. |
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| 6)
After finishing operation Nr. 5, check the clearance
between valve stem and guide using proper devices. Do not
guide yourself by tact or your own experience since a
small gap may cause the stem-guide sticking and a big gap
will cause higher oil consume. Nowadays, the pollution
norms are in force and may be very severe. |
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7)
Observe the erosion grade of the valve seats lodging (on
their base) specially the exhaust. . If necessary,
mechanize the lodging, verify the specifications with
proper instruments to ensure a good fitting. Do not use
any type of adhesive to fix valve seats.
During the valve seat mounting liquid nitrogen may be used.
Ensure there is a good contact between valve seats and
their lodging in the cylinder head. |
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8)
Ensure there is a correct concentricity with the guide
centerline using any method of valve seat mechanizing.
Keep the work area clean. (use clean cloth). |
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9)
Ensure there is a correct concentricity between the valve
seat and the guide using a device with dial indicator. |
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| 10)
Select the correct 3B engines valves from the catalog. |
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11)
After mechanizing the elements from the cylinder head,
verify the height of the valve with reference to the
cylinder head plane according to the engine manufacturer
specifications. |
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| 12)
Verify that valve and seat close down correctly using
vacuum gauge method. |
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13)
Do not forget that the use of abrasive paste eliminates
the machining imperfections from the cylinder head
elements but let's remember that this settling process
reduces the useful life of the valves. Try to reduce the
use of the emery paste. |
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| 14)
Number the valves in order to identify their final
location. Use painting or electronic pencil. Do not mark
the valve with stamped dots or impact numbers on the
valves head. |
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15)
Check the working surfaces of the rocker arms. Verify the
tension, length and perpendicularity of the springs
according the OE specifications. These factors are very
important in order to ensure a good performance of the
valves and to avoid early failures. |
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16)
During the cylinder head assembling, clean perfectly all
the elements and the work area. Before installing the
valves lubricate their stems.
Use valve stem seals only on the cylinder heads where are
required from manufacture. Put carefully the valve locks.
Verify that the valve lash is correct and will obtain an
assembly in perfect functional and technical conditions. |
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