Hilicoil ate aluminum thread! Need help.

[Craig Lebakken]

The specifications/formulas for the thread depth requirement
for bolts threaded into metals of different properties,
typically a steel (stronger) material threaded into a weaker
material (aluminum), in order to exceed the maximum strength
of the stronger material, have been published in the
Machinery's Handbook for years. We (at my engineering
office) deal with this problem often. I can guarantee that
Audi did not supply enough material to fail an EM bolt.
Torque values are therefore very important. Does anyone have
a threadlocker for this? One that will maintain the original
torque value, but not make you pay later?

In another experience - Porsche 944T cyl heads are notorious
for failing at the head/block threads. My neighbor used
Timeserts in the block to renew three head bolt threads.
This 944T was then shipped to Europe, where it ran
Silverstone, Hockenheim, etc. He said that Timeserts are the
cat's meow. Since his car has run several F class SCCA
events since, I would have to agree.

FWIW

Craig Lebakken
1986 4KQ