Cylinder Head Bolt Torque

CYLINDER HEAD BOLT TORQUE/SEQUENCE





Tighten cylinder head bolts 1-12 in the sequence shown using a two step torque sequence:
(a) First to 47 Nm (35 ft. lbs.).
(b) Second to 122 Nm (90 ft. lbs.).
(c) After head bolts 1 - 12 have been tightened to specifications, tighten valley bolts A - H in sequence shown to 11 Nm (95 in. lbs.).

CYLINDER HEAD SURFACE VARIATION





Check cylinder head for flatness.
Inspect all surfaces with a straightedge if there is any reason to suspect leakage. If out-of-flatness exceeds 0.019 mm (0.00075 inch) times the span length in inches in any direction, either replace head or lightly machine the head surface. As an example, if a 12.0 inch span is 1.0 mm (0.004 inch) out-of-flat, allowable is 12 x 0.019 mm (0.00075 inch) equals 0.22 mm (0.009 inch). This amount of out-of-flat is acceptable. *Maximum of 0.2 mm (0.008 inch) for grinding is permitted.

CAUTION: This is a combined total dimension of stock removal from cylinder head surface.

CYLINDER HEAD BOLT RE-USABILITY

1. 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.