Having heard several comments about the nuts on the exhaust studs loosening, I
am considering how to avoid this problem. I assume that lockwashers are not
used because they would rust or otherwise fail at the high temperatures
involved. Since the brass nuts don't seem to be totally secure, several
alternative approaches came to mind:
1. Loop a piece of stainless wire around the stud, give it a couple twists,
then wrap two turns around the nut, conforming the wire to the nut's shape,
then twist the ends.
2. Use a 1/2 inch by 1 inch piece of sheet stainless (leftover from the
firewall) with a hole punched in the middle as a sort of washer under the nut.
Bend one end down over the flange, bend the other end up against one of the
flats on the nut.
3. Make a 1 inch diameter washer from stainless sheet. Cut it along radii
at 6 places for 1/4 inch or so. Tighten the nut onto this washer, then bend
alternate sections up over the nut and down over the flange. (Similar to #2
above, but more elaborate.)
Clearly, what I have learned about safety'ing forward of the firewall is: Bend
Metal. Would any of these be worthwhile? Has anyone tried any of the above
approaches?
Comments??
The Rotax manual suggests wrapping a turn of safety wire around the springs
which secure the muffler to the stacks to minimize vibration of these springs.
Also, they suggest filling the springs with high temperature silicone rubber.
Are these steps necessary with the Europa Mk1 exhaust?
A recent suggestion was to add a support at the rear of the muffler to reduce
the load carried by the stacks and thus reduce the chance of cracking. The
obvious approach is a long hangar from the cross tube of the engine mount (so
there is minimal movement between the muffler and the support) to the short
pipe out the rear of the muffler. Perhaps a strip of the stainless sheet here
too? Or, should a tab be welded onto the top of the muffler at the seam above
the outlet pipe? What have others done here?
What is the normal clearance between the rear pipe from the muffler and the
front of the LG? On trial fit I found only 1/8 inch which seems like it will
allow contact at startup/shutdown, when the engine is prone to shake a bit.
Does one apply force to improve the clearance here (thinks: seems crude, but
what's the alternative)?
Any comments or guidance on the above would be appreciated.
John A044
|