PISTON 7Y1258 - Caterpillar

Illustration 1 g01250785
Typical example
Lubricate the threads and the underside of the head bolts with clean engine oil. Tighten the bolts in the sequence that is shown in illustration 1 to the following torque. ... 50 N m (37 lb ft)Tighten the bolts again to the following torque. ... 100 N m (74 lb ft) Tighten the head bolts to the additional amount. ... 225 degreesMinimum thickness of cylinder head ... 150.8 mm (5.93700 inch)
Illustration 2 g01455374Note: The maximum distortion of the bottom face of the cylinder head is given in table 1.
Table 1
Dimension Maximum Permissible Distortion
Width (A) 0.08 mm (0.0032 inch)
Length (B) 0.08 mm (0.0032 inch)
Diagonal Line (C) 0.08 mm (0.0032 inch)
Illustration 3 g02328933
Typical example
(D) Valve guide height from the top of the valve guide to the valve spring seat ... 10.85 to 11.15 mm (0.42716 to 0.43898 inch) (E) Outside diameter of the valve guides ... 11.029 to 11.040 mm (0.43421 to 0.43464 inch) (F) Length of the valve guides ... 43.75 to 44.25 mm (1.72244 to 1.74212 inch) (G) Internal diameter of the valve guides ... 7.007 to 7.020 mm (0.27587 to 0.27638 inch) (H) Valve depths Inlet ... 0.905 to 1.163 mm (0.0356 to 0.0458 inch)The service limit for the depth of the inlet valve ... 1.41 mm (0.0555 inch)Exhaust ... 0.876 to 1.131 mm (0.0345 to 0.0445 inch)The service limit for the exhaust valve depth ... 1.38 mm (0.0543 inch)
Illustration 4 g02474819
Typical example
(J) Diameter of the parent bore in the cylinder head ... 11.000 to 11.022 mm (0.43307 to 0.43394 inch) (K) Seat angle Inlet ... 119.25 degreesExhaust ... 89.25 degrees
Illustration 5 g02475018
Typical example
(L) Seat surface finish ... Ra 0.8 microns (M) Concentricity of valve seat to valve guide parent bore Maximum Total Indicated Reading (TIR) ... 0.08 mm (0.00315 inch)