CYLINDER HEAD & VALVES - CONT - TM-5-3820-256-24-5

CYLINDER HEAD & VALVES - CONT - TM-5-3820-256-24-5_201

CYLINDER HEAD & VALVES - CONT - TM-5-3820-256-24-5_203

TM-5-3820-256-24-5 Drilling System Well Rotary Truck Mounted Air Transportable 600 Feet Capacity Model LP-12 NSN 3820-01-246-4276 Manual
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SERVICE MANUAL CYLINDER HEAD & VALVES Section 3 Figure 28. - Grinding Valve Face Angle d. Replace valve if more than 0.20 mm (0.008 in) stock is removed from valve face angle or if margin falls below minimum specifications. e. Check valve face runout, after resurfacing, with dial indicator. f. Replace valve if runout (in reference to valve stem) is greater than 0.05 mm (0.002 in) total variation in dial indicator reading. g. After resurfacing valves, clean valve guides and check valve face contact with valve seat using Prussion blue as follows: 1. Spread thin film of Prussion blue on valve face. Insert valve into its guide. 2. Apply pressure on exact center of valve head, while making a quarter turn in the seat. 3. Remove valve, inspect impression made on seat and on valve face. 4. Bluing should appear around entire contact surface of valve face and valve seat to be acceptable. CHECK SEVERAL TIMES TO PREVENT ERROR. If acceptable, proceed with valve installation. 5. If bluing DOES NOT show around the ENTIRE contact surface of the valve seat, the angles do not match and are UNACCEPTABLE. If this happens, correct by RESURFACING VALVE SEATS; NOT VALVE FACES. 5. Resurface valve seat as follows: a. Dress the grinding wheel to correct angle. Lightly lubricate and install correct size pilot into valve guide bore. b. Lower grinder head over pilot shank until wheel barely clears the valve seat. Turn on power. GENTLY apply grinding wheel to valve seat with little pressure other than weight of the wheel. c. Raise wheel frequently to prevent overheating. d. Grind seat to a smooth even surface. e. Check seat concentricity, roundness and valve face contact using Prussion blue as previously outlined. f. After grinding seats, it may be found that seats are wider than the specified width, as shown in Fig. 29. CGES-185-3 PRINTED IN UNITED STATES OF AMERICA Page 22

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