Old-style self-locking nuts

[quk@isham-research.demon.co.uk (Phil Payne)]

I'm sure someone on the list can help me out ...

The self-locking nuts used on older Audi manifolds were of a specific
design - there was a slot cut in the side of the top of the nut creating
a kind of spring that pressed on the thread harder than the rest of the
nut did.

I took a set off Roger Galvin's car last weekend, and laughed a little
when he tried to re-use them - you can tighten them to 30 Nm, tap the
manifold with a hammer, and remove them at an undoing torque below 20
Nm.  I fitted new nuts.

Now - the question.  What are these (old) nuts called?

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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