Warning for listers planning turbo rebuild

Phil Payne quattro at isham-research.com
Thu Dec 20 15:34:13 EST 2001

> 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
  +44 7785 302 803
  +49 173 6242039

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