What is the procedure for tightening a torque to yield bolt?

How do you tighten torque to yield bolts?

How to tighten torque to yield bolts

  1. Tighten all bolts in sequence, and in two stages to a snug torque value of say, 30 Nm.
  2. Apply a 90 degree rotation to all bolts in the proper tightening sequence.
  3. Apply a further 90 degree rotation to all bolts in the proper tightening sequence.

What is the proper way to torque a bolt?

Place the socket and torque wrench on the fastener and tighten the bolt, holding the torque wrench by the handle at the end of the wrench. Rotate the torque wrench slowly and smoothly, continuing through the arc until the wrench clicks. The click indicates that you have reached the desired torque.

Should I replace torque to yield bolts?

These bolts cannot and should not be reused due to the stress caused to the bolt during its first installation. … Torque-to-yield bolts may break if reused or become loose over time.

Do you lube torque to yield bolts?

Removing the bolts while the engine is hot can cause cylinder head warpage. … Using engine oil, lightly oil the threads and under the heads/washers on T-T-Y bolts unless otherwise specified by the vehicle service manual. Clean, oiled threads prevent binding, allowing for accurate and consistent torquing.

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What happens if you over torque a torque to yield bolt?

If the bolt is over-torqued and stretched beyond its limit, this exceeds its yield strength which means it can no longer maintain the needed clamp load and must be replaced. … Finally, using a breaker bar, the bolt is tightened, which moves the dial to the specified angle – hence the term torque-angle.

What is the tightening torque?

Torque tightening is the accurate application of torque to a nut so that a bolt can hold its load securely without breaking. … When you apply the right amount of torque, the bolt is properly stretched so that it can act as a solid spring to clamp the two materials together.

How is tightening torque calculated?

In the tightening direction, begin to slowly apply force to the tool until the first movement in the fastener is noted. The reading recorded is a good indication of the original torque applied to the joint. This is the best way to determine residual torque.

Is code for bolt tightening?

10 Snug Tight – The level of tightness attained by a few impacts of an impact wrench or by the full efforts of a man using a Standard/ podger spanner or a spud wrench. Bolts, nuts and washers shall conform to IS 3757 : 1985, IS 6623 : 1985 and IS 6649 : 1985 respectively.

How many times can torque to yield bolts be used?

* Never reuse a torque-to-yield bolt. Because the bolts are designed to stretch once, stretching them a second time may stretch them beyond their yield point causing the bolt to break. They are one-time use bolts, so throw the old bolts away and buy new ones.

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How tight should head bolts be?

If an engine produces 1,500 pounds of pressure and the cylinder head has 8 bolts, then each bolt must be tightened to 187 foot-pounds of torque to secure the cylinder head to the block.

Why do manufacturers use torque to yield bolts?

Many vehicle manufacturers use torque to yield bolts; especially on engines with aluminum heads and or in conjunction with (MLS) head gaskets. Because, they provide more consistent clamping loads, across the entire head-to-block mating surface. … Reusing the old bolts, can cause expensive engine failure.

Why are some bolts torque to yield?

Traditional fasteners are torqued to a load that will slightly stretch the bolt but won’t over-stretch it past its yield point. Torque-to-yield (TTY) fasteners are stretched beyond the point of elongation to ensure a more consistent clamp load on the joint.