Cylinder Head Bolt Torque

CYLINDER HEAD BOLT TORQUE/SEQUENCE




Cylinder Head Bolt Torque Sequence





Cylinder Head Bolt Torque Chart

CYLINDER HEAD SURFACE VARIATION

Inspect all surfaces with a straightedge if there is any reason to suspect leakage. If out-of-flatness exceeds 0.00075 mm/mm (0.00075 inch/inch) times the span length in inches in any direction, either replace head or lightly machine the head surface.
FOR EXAMPLE: A 305 mm (12 inch) span is 0.102 mm (0.004 inch) out-of-flat. The allowable out-of-flat is 305 X 0.00075 (12 X 0.00075) equals 0.23 mm (0.009 inch). This amount of out-of-flat is acceptable.
The cylinder head surface finish should be 1.78 - 3.00 microns (70 - 125 microinches).

CYLINDER HEAD BOLT RE-USABILITY

Cylinder head bolts should be carefully examined before reuse. If the threads are necked down, the bolts should be replaced.





NOTE: Necking can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale, the bolt should be replaced.