These are a few pictures and notes abput the installation of the in-cowl muffler system.

• Apply a thin layer of anti seize compound internal to all slip joints
• Assemble the system on the bench
• Install new gaskets on engine
• Install the muffler system and tighten nuts (use anti seize) to 400 in/lb
• Install the tail pipe.  drill through for the 1/4" rivet, install the rivet and clamp.
• Tighten clamp just enough to retain rivet and not vibrate.  Do not tighten hard.
• Rotate the muffler / tailpipe for best angle to clear firewall / other items under the cowl
• Fabricate a stainless steel strap to restrain muffler in this location.  From bracket on muffler to suitable please on the engine.

All,

Just to report that I received an early Christmas gift from Jan - my
new in-cowl muffler arrived and I installed it this weekend. The
package comprises the muffler, my 2 reworked header pipes, four slip
jointed sections and the tail pipe. The tail pipe is held on in the
normal way with a pin jointed clamp.

The assembly went together very well, with just a little tweaking.
I had to trim both of the pipes entering the muffler by about 1/4".
I strongly recommned, from the school of hard knocks experience,
that you try to assemble the whole thing together before you start.
If you bolt the headers in place first, then, due to the length of
the slip joints and the tolerances with the muffler, it ain't goin'
to fit!!!!

Assemble it all together beforehand, slip tubes 'slipped' to the
maximum inside each other, and get the orientation right first and
if the slip joints move too much, put some tape temporarily around
the pipes to keep them in position while you lift the whole assembly
up vertically from the bottom. You need at least 3 hands. One to
hold the assembly and get the headers over the cylinder head studs,
one to twist the slip joints to get the right alignment, one to
thread on the stud nuts, and one to hold the ratchet wrench, and one
to hold the exhaust manifold gasket in place....... all at the same
time.

Once it was in place and the header nuts tightened down firmly, I
then adjusted the muffler box sideways and front/back/up/down with
gentle but judicious use of a rubber hammer so that I had both
clearance from the oil pan, and had the tail pipe clearing the nose
gear/engine mount tube pyramid, and oriented the way I needed. Once
set, I tightened the header nuts, drilled for the pin clamp for the
tail pipe and fixed that, then I used my existing support clamp and
bolted it from the rear flange on the muffler back up to the
original engine mount plate attach point.and then sat back looked at
it for a while and took some photos. I'll put them up this week.

Of course I had some questions that Jan answered promptly: Do I
need clamps for the slip joints? No - they need room to
expand/contract. Do I need lock/split washers for the header nuts -
NO. .....and don't forget to torque and recheck the nuts before and
after the first flight...

Hope thsi helps someone...

Allan
RV-9A + H-6 - 59 hours, waiting for G3......

HOW TO REPACK THE OLDER SUPERTRAPP MUFFLERS NO LONGER USED.