TM-9-2815-220-34 Direct Support Manual for AVDS-1790-2C and AVDS-1790-2D Engines Download
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TM 9·2815·220·34 (2) Valve 3eau. Replace cylinder assembly (5, fig. 3-1Z) when inserts are cracked, lꝏse or excessively worn in the cylinder. Grind seats which do not show 360° contact with valve face. Grind inserts (fig. 3-1c) as described in (a) and (b) below. (a) A 45 degree angle grinding stone must be used to grind exhaust valve seat and a 15 degree angle grinding stone must be used for intake valve seats. Dress seat on the insert with stone, using valve seat grinding machine. After dressing seat of insert, check valve contact as described in paragraph 8-71b. {b) When 3<° contact is obtained, narrow seat on insert to width specified in figure (3·1c) by grind- ing inner wall and exposed face of insert to the angl specified. Keep valve seat area as near possible to center of valve face. Valves should never seat at the top or bottom of the valve face area. 15° 15' 1 HIN S - EAT ANGLE O.osgo MI N INSE R T SEAT WIDTH ( NE W ) - 0. 0990 X 0.0<0 MIN ooo 45° ·� p - 00' MIN SEAT ANGLE (MAX) INTAKE VALVE EXHAUST VALVE SEE NOTE 1 REGRIND ON THIS LIN� 45 0 + 15' WHEH WIDTH OF VALVE . SEE NOTE l INSERT EXCEEOS �iJ: ' � � NOTE 1 NEW INTAKE VALVE 6.355 TO 6,369 EXHAUST VALVE 7.010 TO 7.024 REPAIR 6.3740 7.0340 NOTE. ALL OIMESIONS SHN ARE IN INCHES. TA 1261541 figure 3·1c. Valve and valve ot irt grinding diogrom. b. Cylinder Bore. Replace cylinder assembly when cylinder bore dimensions are not within limits specified in the repair standards (table 3-13), or when average dome end measurement is larger than average flange end measurement. The cylinder assembly should also be replaced when the cylinder bore has excessive scratches, scoring or ring ridge or when the bore is glazed or smꝏth. c. CamJliaft Bearins SleeveJ. Fine scratches on the bearing surface are not cause for rejection. Replace camshaft bearings when the bearing surfaces are scored, galled, or deeply pitted, or when arings do 3-108 Change 2 not conform to the limits specified in the repair stan- dards (table 3-13). d. Cylinder Exterior. (1) Cooli+s m. Straighten bent fins as near pDible to their original spacing. Replace cylinder aasembly when more than one percent of barrel cꝏling fin area is broken. Replace cylinder aasembly if head fin is broken more than half the depth of the fin or more than two inches long. A cylinder assem- bly can be used if it has not more than thr ac- ceptable defects, or if no two of the defects are on ad- jacent fins. Repair damaged cylinJer head fins ꜳ ) )