What are the possible effects of over torquing or under torquing?
When the joint in question is over-torqued, the flange load can become uneven and weaken the effectiveness of the flange/bolt load. This in turn leads to an increase in blow-out pressure and hydrostatic force, which can cause joint failure.
What happens if you over torque a cylinder head?
When you overtorque above 15% of recommended which in this case would be about 95 ft/lbs you basically turn the fastener into a rubber band. Some of the fasteners will stretch and you will have uneven torque. Add heat and pressure and head gasket blows and the head can even warp.
How to get the torque on aluminum heads?
Make sure you are using hardened washers with your bolts on aluminum heads. Moly the thread and the washer up real good. Give each bolt a nice even pull till you get to torque. Don’t jerk the bar and try to use the same arm and pull geometry on each bolt.
What happens when torque is applied to a head bolt?
The amount of torque applied to the head bolt accomplishes two things. First, it overcomes friction between the threads in the block and the bolt as well as friction between the cylinder head the underside of the bolt head.
Why are you not supposed to over torque fasteners?
Since fasteners can be made from different materials ranging from soft metals to heat-treated hardened ones, the torque that can be applied to the fastener will depend on the material the fastener is made out of. For example, an aluminum bolt will not be able to take nearly as much torque as a Grade 8 bolt.
When you overtorque above 15% of recommended which in this case would be about 95 ft/lbs you basically turn the fastener into a rubber band. Some of the fasteners will stretch and you will have uneven torque. Add heat and pressure and head gasket blows and the head can even warp.
The amount of torque applied to the head bolt accomplishes two things. First, it overcomes friction between the threads in the block and the bolt as well as friction between the cylinder head the underside of the bolt head.
Can a torque wrench be used to tighten head bolts?
It won’t give you the accurate torque readings you need when torqueing down the head bolts. Save yourself a headache – use a high-quality torque wrench to tighten the head bolts in at least 3 steps. Tighten until you get to the needed torque specification.
Since fasteners can be made from different materials ranging from soft metals to heat-treated hardened ones, the torque that can be applied to the fastener will depend on the material the fastener is made out of. For example, an aluminum bolt will not be able to take nearly as much torque as a Grade 8 bolt.