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

The Rotary Engine NewsLetter. Powered by Linux.
ACRE NL web site. http://www.rotaryeng.net
Copyright 1998-2006 All world wide rights reserved.