How to torque a bolt
From Crankshaft Coalition Wiki
To properly torque a bolt/nut the following must be done;
- Make sure all threads are clean and are the right fastener for the part. Right thread pitch, length.
- Lubricate the threads with a suitable lubricant.
- Consult the manufacturer's fastener tighting chart whenever possible (all threaded fasteners have different torque values based on bolt/nut grade, size, tread pitch, material and if lubed or dry).
- Bolts of different sizes are torqued in different steps. Smaller diameter bolts are generally torqued in one step. Larger bolts are generally torqued in 3 stages. 1/4 of the torque spec, 1/2 of the torque, then full torque. For example, if cylinder head bolts are supposed to be torqued to 90 foot-lbs, then they would be torqued first to 30, then to 60, and finally to 90.
- All bolts/nuts should be snug or finger tight before torquing. This will ensure the proper torque requirements are met.
Should you re-torque a fastener, you must first loosen it, then completely torque it.
