TM-9-2815-220-34 Direct Support Manual for AVDS-1790-2C and AVDS-1790-2D Engines Download
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TM 9-2615-220·34 Table 3-1 I. Pi ston s, Piston Ring8 and Piston Pins Repair Stn -Continued Fig. Ref. Point of Sizes and fits Wea Comnent No. letter measurement of new parts limits 3.183 r Inside width of lop intermedi- 0.0990 0.10 0.1035 ate groove in piston 3·183 s Inside width of lower inter- 0.0980 0.0990 0.1025 mediate groove in piston 3.)83 t Inside width of oil control ring 0.1880 0.18Z 0.1910 grꝏve in piston Piston 3-183 g Inside diameter of piston pin 2.1268 2.1270 2.1280 bore in piston Piston pins 3-183 f Outside diameter of piston pin 2.1250 2.1252 2.1248 3-183 g-f f'it of piston pin in piston 0.0016L 0.0020L 0.0032L Piston rings 3-183 h Gap clearance of top compres- 0.0250 0.0350 • sion ring when fitted in gage 3-1 j Outside width of top inter- 0.0925 0.0935 • mediate compression ng 3-1 r-j Clearanc between ng and 0.0055L 0.0075L O.OllOL piston 3-1 k Gap clearance of ring when 0.0250 0.0350 • fitted in gage 3-183 aa Outside width of lower com- 0.0925 0.0935 • pression ring 3-183 s-aa Clearance between ring and 0.0045L o.0&5L O.OlOOL piston 3-183 m Gap clearance of ring when 0.0250 • 0.0350 • fitted in gage 3-13 n Outside width of oil control 0.1855 0.1865 • ring 3-183 t-n Clearance between ng and 0.15L 0.0035L 0.0055L piston 3-13 p Gap clearance of ring when 0.0350 0.0450 . fitted in gage 3-1Z c Cylinder bore diameter measured up 2.250 inch'es from bottom of cylinder skirt STD 5.7510 5.7530 5.7:0 0.0100 oversize 5.7610 5.7630 5.7680 0.02 oversize 5.7710 5.7730 5.7780 0.03 oversize 5.7810 5.7830 5.7880 0.04 oversize 5.7910 5.7930 5.7980 3-183 u-·c ' Fit of piston in cylinder bore, O.OOOOL 0.0120L 0.200L 3 -Lꝃ measured up 2.250 inches from bottom of cylinder skirt, Z degrees to piston pin Refer to paragraph 3-37c for explanation of symbols. 3-66. Repair a. Replace pistons which are distorted, cracked, worn, abl'aded, or if oil holes in the ring lands can- not be cleared, or if lands are damaged or broken. Replace pistons that are badly bured, t 1 icked, or scratched. Remove minor burs, nicks or sc1·atches from pistons with crocus cloth dipped in dry-clean- within limits specified in repair standards (table 3-11). Replace oil control rings if drain holes cannot be cleared. B i ng solvent (P-D-680, Type TI). Replace pistons which are not within limits speced repair standards (table 3-11). b. Piston rings cannot be repaired. Replace rings that are scuffed, chipped, scratched, or when they show signs of abrasion. Replace rings when not 3·96 .2 Change 3 c. Replace all piston pins which are cracked, or have deep nicks or scratches. Remove minor nicks or scratches with crocus cloth dipped in dry- cleaning solvent (P-D-680, Type II). Replace piston I pins that are not within limits specified jn repair standards (table 3-l 1 ) . 3-67. Assembly a. Check marking on rings and install the upper (tapered) compression ring and the two inter· ) )