>>> Hello all-
    >>>
    >>> I went with the helicoils.  The timeserts do look better, but
   there was
    >>> no way I was going to try to both tap and counterbore.  Given
   my track
    >>> record with tapping, I figured it was going to be challenging
   enough.
    >>
    >>
    >> I've never seen a Timesert break, come out with the screw or
   back out
    >> from vibration.  I've seen all of the above with Helicoil,
   especially in
    >> aluminum.
    >>
    >> I distrust Helicoil so much, I once walked for a week (waiting
   for the
    >> Timesert kit over a Christmas holiday) rather than using a
   Helicoil that
    >> was at the auto parts place two blocks away.
    >>
    >> Keith Wood
    >
    >
    > Obviously Keith just doesn't like Helicoils. <g> But, I think we
   can all
    > see
    > the source of these problems. When you break these bolts in the cast
    > portion, you are just twisitng too darn hard. For me, the
   solution many
    > years ago was using a speed handle to run up and tighten with one
   hand just
    > twisting on the crank part like a big screw driver. This put out
   just the
    > right amount of pressure to compress the gasket. It also didn't
   break off
    > any more bolts. Cleaning bolt holes and learning the proper
   amount of twist
    > (torque) solves a lot of these kind of problems. It ia sort of
   one of those
    > ounces of prevention, pounds of cure things; and, it also doesn't
   require
    > too many coil/thread replacement repairs.  This stuff can
   actually be more
    > fun sometimes with out self induced extras.
    >
    > jofarr, soddy tn


   These things haven't happened to ME, because I don't use Helicoils in
   the first place.  I've seen them happen to everyone I know who uses
   Helicoils, but I use Timeserts exclusively.

   However, I would point out that no amount of "technique" will prevent
   Helicoils from backing out or coming out with the screw.  Nothing holds
   the Helicoil in place besides whatever friction there is between the
   coil and the hole that it's driven into.  Timeserts are swaged in place.

   Keith

   I am sure they are OK but Key Locks are better than Timeserts IMHO
   as they are
   positively locked against rotation. The big advantage of helicoils
   are low cost
   and availability. They work fine for the oil pan as it is almost
   never removed
   in a rotary engine in service. When the engine is overhauled... that
   is the time
   for the inserts to be installed in the aluminum rotor housing. They
   are unnecessary
   in the cast iron end housings. As somebody said on here; "enough
   about heli coils
   and inserts already" :)

   Paul Lamar


While Helicoils obviously have their flaws, I believe they are standard
on aircraft spark plug threads.  I know some people have had failures
there, but I have removed and installed hundreds of spark plugs and
never had one misbehave.  I almost always use a torque wrench and
anti-seize, as specified however.


Regards,

Matt-



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