Engine components, including the cylinder head, require specific applications of torque or tightening in order to attach them properly. Because torque specifications are unique for different engines and bolts, no short list of them is possible. Refer to your manufacturer's maintenance guide for specific requirements for your vehicle.
When applying torque, a torque wrench is necessary. Unevenly applying torque can cause the component to become warped, distorted or damaged. Properly calibrated torque wrenches are easy to use and provide accurate applications of torque.
Some heads require torque to be applied to the bolts in a helical sequence. The sequence begins with the middle-most bolt, and then works outward almost in a spiral... that is to say, you should work outward in both directions so that the torque applies evenly throughout the component. This sequence eliminates the chance for the component to become distorted or warped.
If your head has multiple torque steps, apply the first step to all of the bolts in a helical sequence, then apply the next step to all of the bolts in the same sequence exactly. Because the application of torque is essentially stretching the bolts, you should wait about 15 minutes between each step to allow the bolts to settle.
