About three years ago I shopped for a shop to
repair/OH/rebuild my aircraft's exhaust systems. At issue were all four complete
assemblies off a B55. All were in ratty shape, having accumulated 5500 hrs TIS
over 30 years. I suspected that rather than be repaired, all four sides would
have to be rebuilt or replaced with new.
Besides asking for Beech List suggestions, I considered and in
some cases contacted:
Planexhaust (different shop than above)
Custom Aircraft Parts
I concluded that all of the above enjoyed good reputations and
all but one had competitive pricing; see below. And my notes say Aircraft Spruce
resells AWI exhausts.
The first five shops on my list all say they'd "overhaul" my
exhaust systems. Most of the five would return them with 8130s, but at least one
wouldn't, leaving the airworthiness determination up to my mechanic.
As you probably know, overhauling a system often involves
reusing just a small part of the old exhaust assembly -- perhaps the flanges, or
even one flange -- and fabricating everything else from new material. I guess
this approach means the shop doesn't need an STC or a PMA.
Here are prices, from my notes. The figures are for both sides
of a single IO470L:
Wall Colmonoy (OH): $1466
Dawley, (OH): $1494
AWI (direct, OH): $1790
Knisely (OH): $2,257
Plane Exhaust (new): $2360
Custom Aircraft (repair): between $800 and $1200, depending on
condition of originals. $400 to "inspect and recertify"(?) Planexhaust (repair):
Depends on condition
Aircraft Spruce (new, AWI?): $1997
RAPID (new): approx. $11,000
Again, these prices were as of April 2007.
I went with Dawley, not only because of price but also because
I heard good things about the shop.
I wasn't disappointed. The OHed exhausts I received back
consisted of all new metal; I don't know what was reused. Good turnaround; no
Everything fit; no issues at all, so far.
Side note: I sent the pieces for one engine first and for the
second engine a few weeks later. A side-by-side comparison of the pieces I got
back showed a visible difference in the aesthetic quality of the welds. But
structurally I'm confident everything is fine.
I've heard good things about all the "national" shops on the
above list. (I consider Custom Aircraft and Planexhaust to be "local" shops.)
And I used AWI on another repair project years ago and was happy in all
BTW, be sure to check RAPID. When I needed a tailpipe for my
H35 several years ago, it was the best supplier (price, availability,
Finally, a good welder can often repair an exhaust quite
successfully. Years ago a local welder (learned the trade in the Marines,
working on WWII Corsairs and such) repaired the exhaust manifold of my H35. The
repair involved welding a largish patch in the existing metal. It was at least
13 years ago and the assembly is still soldiering on without any noticeable