I personally think torque values are crucial. The specified torque
applies the correct tension to hold what ever, and it should not back
off once tightened. Some torque values are extremely critical and
failure to observe them can result in a failure of a part which in turn
may cause failure of the whole engine or whatever. Could become a safety
issue big time.

Back in my aviation school days it was hammered in that every bolt had a
torque value that was worked out by the engineers for specific reasons,
and those values were to be observed absolutely. There is no place in
flight to pull an airplane over to park because some part failed or fell
off because the correct tourque was not applied.  Aircraft bolts and
nuts are often safety wired to prevent them from backing off. Sometimes
that doesn't help though. I saw a case where one of the cylinders on an
aircraft engine separated from the case because the cylinder flange hold
down stud nuts - even though saftied - were not torqued correctly.
Resulted in the failure of the studs, allowing the cylinder to come
loose in flight. Bad news. So if there is a torque value given, use it.
May save your butt.

One other principle from aircraft mechanic school. If there is no
specified torque, use a standard torque value for the bolt size. Barring
that, go finger tight and a 1/4 turn.

John Rodgers
88 GL Driver

Marla Stelk wrote:
>
> So just how important is it really to use a torque wrench?  A mechanic I spoke to once said he never uses one for tune-ups.  But the Bentley tells you to use one for almost everything.  I've got to take the top off my thermostat - do I really need to go buy a torque wrench to put it back on?  The buggers are pretty expensive.....
>
> Thanks,
> Marla
> '87 Westy Van "Morrison"Get more from the Web.  FREE MSN Explorer download : http://explorer.msn.com