Dear All,
I have just purchased a third set of Classic exhaust downpipes. The original
rear
port downpipe (mild steel) fractured and blew a hole on the outside of the
bend after 485 hours. This affected the engine so badly that I had to limit
the power to produce an extended glide to make an emergency down wind landing.
I replaced the whole exhaust system (stainless steel).
I have just discovered a hairline fracture with grey exhaust deposit on the
outside
of the bend on the starboard rear downpipe, so I have purchased a set of
replacement downpipes at 936 hours. I may decide to replace the lot, or both
rear, or one pipe at a time, to see how the others last, but I am not quite
sure.
It might be useful if others who have had to replace all or part of the exhaust
systems, on either Classics or XSs give a short report so that we can see if
there is any trend associated with hours and position of any fracture.
I thought the first fracture might have been caused by the box having to hang
off
the down pipes, causing additional stress when operating over rough ground,
so I asked Andy to weld some hanger lugs on the replacement box so that I could
support it off the crankcase at the front and off the engine bearers at the
back, but that did not appear to be any help. In fact the second set only
lasted
451 hours!
If anyone has any bright ideas, I would be most interested.
Still on exhaust matters, has anyone tried to seal the leakage from the spigot
and socket joints between the down pipes and the box stubs? I still get some
CO in the cockpit when climbing under full power, so I was thinking of sealing
them with RTV silicone. Has anyone tried that?
Best wishes,
William
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