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305-350 ENGINE
6A6-9
Fig.
6A6-1 1
Compressing Valve Spring
Fig.
6 A 6 - 1 3
Cleaning Valve Guides
Fig.
6 A 6 - 1 2
Cleaning Combustion Chambers
3. Measure valve stem clearance (Fig. 6A6-14) as
-
follows:
Clamp a dial indicator on one side of the cylinder head
rocker arm cover gasket rail, locating the indicator so that
movement of the valve stem from side to side (crosswise to
the head) will cause a direct movement of the indicator stem.
The indicator stem must contact the side of the valve stem
just above the valve guide. With the valve head dropped about
1/16" off the valve seat; move the stem of the valve from side
to side using light pressure to obtain a clearance reading. If
clearance exceeds specifications it will be necessary to ream
valve guides for'oversize valves as outlined.
4. Check valve spring tension with Tool J 8056 spring
tester (Fig. 6A6-15).
NOTE: Springs should be compressed to the specified
height and checked against the specifications chart.
Springs should be replaced if not within 10 Ibs. of the
specified load (without dampers).
5. Inspect rocker arm studs for wear or damage.
Assembly
1. Insert a valve in the proper port.
Fig.
6 A 6 - 1 4
Measuring Valve Stem Clearance (Typical)
2. Assemble the valve spring and related parts as follows:
a. Set the valve spring (with damper if used), valve shield
and valve cap in place (Fig. 6A6- 16).
b. Compress the spring with Tool J 8062.
c. Install oil seal in the lower groove of the stem, making
sure that the seal is flat and not twisted.
d. Install the valve locks and release the compressor tool,
making sure that the locks seat properly in the upper groove
of the valve stem.
3. Install the remaining valves.
4. Check each valve stem oil seal by placing Valve Seal
Leak Detector (Tool J 23994) over the end of the valve stem
and against the cap. Operate the vacuum pump and make
sure no air leaks past the seal (Fig. 6A6-17).
5. Check the installed height of the valve springs, using
a narrow thin scale. A cutaway scale will help (Fig. 6A6-18).
Measure from the top of the shim or the spring seat to the
top of the valve spring or valve spring shield (Fig. 6A6-19).
If this is found to exceed the specified height, install a valve
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