NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
Page 196 of 1014
NMWR 9-2815-220 CYLINDER ASSEMBLY OVERHAUL—Continued 0012 00 INSPECTION – Continued 4. Valves inspection. (a) Valve head. Inspect the intake and exhaust valves for cracks using dye penetrant method. Also inspect for evidence of pitting, imperfect seating, or warpage on valve head. Heavy discoloration, burning, erosion, or a heavy carbon deposit on the valve face indicates a warped valve. A light frosted appearance or minor discoloration on the valve does not indicate a warped or unserviceable valve. (b) Valve stem. Inspect valve stem for cracks using dye penetrant method. Do not mistake edge of chrome plating on stem for a crack. Also inspect the stems for pitting, scoring, or damaged tips. Measure valve stem outside diameter, seat angle, width of locking groove, length, and gage diameter for wear. 5. Refer to WP 0005 00 and the OIPs in Table 2 for specific inspection criteria for selected items. 6. Discard all mandatory replacement parts. Refer to Figures 14 and 15. Table 2. Components Requiring Overhaul Inspection. COMPONENT OIP Engine cylinder head standard (item 1, Figure 14) 10951221 (Table 4) Valve rocker support cover (item 13, Figure 14) 7320420 (Table 5) Valve adjusting access cover (item 2, Figure 15) 7320408 (Table 6) Exhaust engine poppet valve (item 11, Figure 15) 11610010 (Table 7) Intake engine poppet valve (item 12, Figure 15) 10951239 (Table 8) Engine poppet rocker arm (item 16, Figure 15) 8725281 (Table 9) Machine thread plug (item 18, Figure 15) 7320384 (Table 10) Intake valve rocker arm straight shaft (item 19, Figure 15) 7320394 (Table 11) Exhaust valve rocker arm straight shaft (item 20, Figure 15) 7320393 (Table 12) Exhaust engine poppet rocker arm (item 21, Figure 15) 8725293 (Table 13) RECLAMATION 1. Worn intake valves (part no. 10951239) can be reclaimed by arc welding according to the following procedure. Refer to Table 7. NOTE Quality Control will inspect finished parts to ensure adherence to this procedure. (a) Using a suitable valve grinding machine, undercut the valve face as necessary to eliminate the surface defects. (b) Attach the valve to a 12-in. (304.8 mm) aircraft welding turntable to obtain proper rotation while welding. (c) Using the semi-automatic gas tungsten arc welding process, weld the machined surfaces of the valve seat. Use standard 1/8 inch x 14 inch welding electrodes in accordance with MIL-R-17131C(1) and AWS 5.10/5.10M. (d) Overbuild the weld sufficiently to allow for finish grinding of the welded surface. (e) Using valve grinding machine, finish grinding the valve to drawing specifications (DWG 10951239). 0012 00-6 Change 1