Valve: Testing and Inspection
VALVE INSPECTION1. Clean valves thoroughly and discard any burned, bent, warped, and cracked valves.
2. Measure valve stems for wear.
NOTE: Valve stems are chrome plated and should not be polished.
Intake And Exhaust Valves:
VALVE GUIDE
1. Remove carbon and varnish deposits from inside of valve guides with a reliable guide cleaner.
2. Measure valve stem guide clearance as follows:
3. Install valve into cylinder head so it is 14 mm (0.551 inch) off the valve seat. A small piece of hose may be used to hold valve in place.
Figure 82 Valve Guide Wear Measuring:
4. Attach Special Tool C-3339, dial indicator to cylinder head and set it at right angle of valve stem being measurer.
5. Move valve to and from the indicator. If guides are out of specifications ream to next oversize.
6. Ream the guides for valves with oversized stems if dial indicator reading is excessive or if the stems are scuffed or scored.
7. Service valves with oversize stems and over size seals are available in 0.15 mm (0.005 inch) and 0.40 mm (0.015 inch) oversize.
NOTE: Oversize seals must: be used with oversize valves.
8. Select the correct size reamer to accommodate the oversize valve stem.
9. Slowly turn reamer by hand and clean guide thoroughly before installing new valve. Do not attempt to ream the valve guides from standard directly to 0.40 mm (0.015 inch). Use a step procedure of 0.15 mm (0.005 inch) to 0.40 mm (0.015 inch), so the valve guides may be reamed true in relation to the valve seat. After reaming guides, the seat runout should be measured and resurfaced if necessary.
NOTE: Replace cylinder head if guide does not clean up with 0.40 mm (0.015 inch) oversize reamer, or if Guide in Inner in cylinder head.
Figure 83 Valve Spring Testing With Special Tool C-657:
TESTING VALVE SPRINGS
Whenever valves have been removed for inspection, reconditioning, or replacement, the valve springs should be tested. The valve springs have two springs, a inner spring and an outer spring. The two springs should be separated before testing them for tension.
CAUTION: Be sure to identify the springs because they are to be used in matched pairs only. When replacement is necessary replace springs as a pair do not replace only inner or outer springs.
As an example: the compression length of the spring to be tested is 33.34 mm (1 - 5/16 inch). Turn table of Special Tool C-647 until surface is in line with the 33.34 mm (1 - 5/16 inch) mark on the threaded stud and the zero mark on the front. Place spring over stud on the table and lift compressing lever to set tone device. Pull on torque wrench until ping is heard. Take reading on torque wrench at this instant. Multiply this reading by two. This will give the spring load at test length. Fractional measurements are indicated on the table for finer adjustments. Refer to specifications to obtain specified height and allowable tensions. Discard the springs that do not meet specifications.