PISTON AS 1521390 - Caterpillar

(1) Bore in rocker arm for shaft ... 24.803 0.013 mm (.9765 .0005 in) Diameter of rocker arm shaft ... 24.752 0.013 mm (.9745 .0005 in) (2) Put 6V4876 Molykote Paste Lubricant on all the threads of bolts that hold rocker arm shafts and tighten the bolts in the step sequence that follows:1. Tighten bolts from 1 through 6 in number sequence to ... 270 25 N m (200 20 lb ft)2. Tighten bolts from 1 through 6 in number sequence to ... 450 20 N m (330 15 lb ft)3. Tighten bolts from 1 through 6 in number sequence again to ... 450 20 N m (330 15 lb ft)(3) Torque for locknut for valve adjustment screw ... 30 4 N m (22 3 lb ft)(4) Torque for locknut for bridge adjustment screw ... 47 9 N m (35 7 lb ft)(5) Valve Lash: Inlet valves ... 0.38 mm (.015 in)Exhaust valves ... 0.76 mm (.030 in)(6) Height to top of dowel ... 53.3 0.5 mm (2.10 .02 in)(7) Diameter of dowel ... 11.008 0.003 mm (.4334 .0001 in) Bore in bridge for dowel ... 11.13 0.05 mm (.438 .002 in)Bore in head for dowel ... 10.968 0.020 mm (.4318 .0008 in)(8) Diameter of valve lifter ... 27.896 0.013 mm (1.0983 .0005 in) Bore in block for valve lifter ... 27.953 0.019 mm (1.1005 .0008 in) See Guideline For Reusable Parts; Salvage Of Lifter Bores In 3400 Series Engines, SEBF8069 for the procedure, tooling and specifications needed to install 4W4588 Sleeves for salvage of the lifter bores in the cylinder block.(9) Guide springs must not be used again. Always install new guide springs. (10) 2N7229 Spring: Length under test force ... 74.2 mm (2.92 in)Test force ... 45 to 53 N (10 to 12 lb)Free length after test ... 114.3 mm (4.50 in)Outside diameter ... 29.7 mm (1.17 in)(11) Dowel length above top surface of rocker shaft support to be ... 12.7 1.0 mm (.50 .04 in)(12) Clearance for rocker arms (both ends) ... 0.30 to 1.40 mm (.012 to .055 in)(13) Use 2N7228 Washer as needed to get clearance (12).
Typical Example(A) Minimum dimension after reconditioning ... 16.51 mm (.650 in)(B) Allowable wear before reconditioning ... 0.13 mm (.005 in)Inspect the bridge seats for wear. Use the bridge again if the wear is 0.13 mm (.005 in) or less. When the wear seat is worn more than the allowable limit, the worn surface of the seat can be ground flat. The maximum amount of material that can be removed is 0.38 mm (.015 in). If the seat cannot be made flat, replace the bridge. Reconditioning of the wear seat can only be done once.