Warning for listers planning turbo rebuild

[Phil Payne]

> Lacking experience to feel the needed torque by hand I am scared to
> death to torque exhaust manifold nuts. Some of them spin too much.  The
> spec from Bentley is 30 n/m. Is it right?  What does "pulled stud"
> mean?  A stud is forced out stripping thread on the way?  What is the
> fix?  Drill for larger thread?

30Nm is right.  There are two fixes for pulled threads:

a) Helicoils.  Used where the hole is not badly damaged.

b) Stepped studs.  Used where the hole is very badly damaged, e.g., where some monkey lad has tried to drill out a broken stud with
the head still on the engine.

Both are stronger than the original studs.

--
  Phil Payne
  http://www.isham-research.com/quattro
  +44 7785 302 803
  +49 173 6242039