NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 CAMSHAFT AND DRIVE ASSEMBLIES OVERHAUL—Continued 0016 00 0016 00-5 Change 1 (5) Preheat housing to approximately 150° F (66° C). (6) Apply Metco 445 aluminum bronze powder (MIL-STD-1687A(1)) to the bearing surface using Metco 6P Thermospray or 7MB Plasmaspray System. Coat surfaces sufficiently to allow for remachining of the bore to drawing tolerances. (7) After housing has cooled to room temperature, remove masking and machine cam bore I.D. to 2.5000 to 2.5010 in. (63.5000 – 63.5254 mm). NOTE All mounting surfaces repaired by this process shall be 100% inspected for coating integrity after machining. The coating shall show no bond separation at the coating to base metal interface. The coating shall be free from blistering, cracking, chipping, and frayed edges. There shall be no bleedout of oil or other contaminants through the finished coating. RECLAMATION – Continued (2) Set housing in milling machine and undercut 2.5000 in. (63.5000 mm) cam bore bearing surface by 0.0400 in. (1.0160 mm) or as necessary to eliminate surface defects (Figure 2). Figure 2. Camshaft Gear Housing. (3) Prepare bearing surface in accordance with standard metalizing procedure as follows: a Mask areas, not to be metalsprayed, with suitable grit blast masking material. b Grit blast bearing surface with clean, oil free 25 mesh chilled iron grit or cut an 18 thread lead 0.0200 in. (0.5080 mm) deep. (4) Remove grit blast masking material and remask with suitable thermospray or plasmaspray masking material.