2. Why are Torque-to-Yield bolts
a better choice for clamping?
More consistent torque over wider range of
operating conditions.
Matched to gasket and engine
Head gasket failures are very rare now
7. So…what is happening?
As a bolt begins to
tighten, it enters the
area known as the
“Elastic
Deformation”
Region where the
bolt stretches, but
will return to original
length when
loosened.
8. Example: Connecting Rod Bolt
This special tool will
actually measure
the amount that a
bolt will stretch
when tightened.
9.
10. Let’s tighten the bolt some
more!
As the bolt is
tightened further, it
reaches the “Plastic
Deformation” region.
At this point, the bolt
will not return to its
original length when
loosened. But it will
be a better “Bolt”!
11. But, we can over do it!
It just got real easy
to turn all of a
sudden! At this
point, you can’t back
it off a quarter turn
and save it!
12. Hey! It got real easy to turn
Ok, dumb-bunny.
You didn’t follow the
special “Torque-to-
Yield” directions in
the shop
manual…and now
you have a real
problem!
13. What this looks like-Real World!
1st Step: Base Torque, Mark
Bolts
16. What this looks like-Real World!
4th Step: 45 deg. Turn Center
Bolts
17. Remember!
Always check the shop manual for instructions
for:
Bolt length
Lubrication requirements
Special torque values and procedures
Mark bolts when finished with final torque angle