I just reviewed the section on best practices again.
 Are you guys using a gob of RTV at a point near the center of the bolt or
 is
 there a rubber grommet available specifically for this purpose.
 My bolts had some type of rubber looking substance on some of the bolts
 (not
 all) but they were much worn so I removed it during cleaning.

 Jay

 Put a spiral of red  RTV all along the tension bolt.

 This damps the vibration and prevents the bolt from
 fatiguing at the root of the threads where it screws
 into the front housing.

 Paul Lamar


I tried to put a spiral or glob of RTV on the tension bolts, but it always
got scraped off when installing the bolt and made a huge mess without doing
any good.  It also makes it much harder to remove the bolts and clean the
passages.  Bits of cured RTV get everywhere.

I think Lynn recommends shrink wrap to dampen vibrations.  Most of mine
don't have anything.
--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net <http://n4vy.rotaryroster.net/
http://RotaryRoster.net <http://rotaryroster.net/

Perry Mick broke one and we spent three days looking for the source
of the internal coolant leak out in hot Palm Springs.

Paul Lamar


Yes, I understand that it is a risk.  I am just saying that in my experience
the RTV thing was difficult, messy, and had questionable effectiveness (most
of it seemed to come off anyway).  There is always the possibility that
Perry's bolt was under or over torqued, or defective, or.....

One other factor to consider that I just thought of...  when torquing down
those tension bolts, because they are so long, there is probably a
considerable amount of twist (in a relative sense) between the head and the
threads.  That twist and spiral load on the bolt (which remains even after
the wrench is removed) probably causes significant weakening and
unpredictable stress risers.

I wonder if we should be backing off the bolt head a few degrees after
torquing is complete.  OTOH, maybe (but unlikely) that twist in the bolt
helps dampen any vibration.  Bruce T. makes a big point in his video to
clean out the threads to minimize any sticking in the threads that would
tend to increase that twist.

Is it possible that excessive bolt twist is responsible for the failures we
have seen rather than vibration?