In a cylinder head bolt torque sequence, which bolts should be torqued last?

In a cylinder head bolt torque sequence, the bolts that should be torqued last are those furthest from the center. This practice is important for several reasons.

First, torquing the outer bolts last helps ensure that the cylinder head seats evenly against the engine block. By starting with bolts closest to the center and progressing outward, the pressure is applied in a controlled manner, allowing for a proper sealing surface and preventing distortion of the cylinder head. The outermost bolts, being the last to be torqued, allow for the uniform distribution of force across the entire head.

Additionally, this sequence helps to avoid any potential warping of the cylinder head that can occur if the outer bolts are torqued first. If the outer bolts were torqued before the inner ones, it could create uneven pressure that may lead to gasket failure or poor sealing performance. Therefore, the correct approach is to torque the outer bolts last, ensuring optimal head stability and integrity throughout the operation of the engine.