Hi Bud, Many thanks for your input on this. Interesting to hear about the
problems
you've had too. Just to give you some data from me, my problem has been both
the rear pipes cracking, ie cyls 3 and 4. I first found them both cracked
together after about 15 hours flying on my new engine installation. They were
both cracked about 75% around the circumference inside the tightest part of the
bend. They may have been like that for quite a while as they are almost
impossible
to spot without a mirror when in situ. It was taking no. 3 off to fit
the new HD starter I quite by chance found it cracked. I had them both welded
up. After about 2 more hours flying I found no. 3 cracked again, following
almost
exactly the same line as the first time (but not quite on the weld repair
- it was fresh metal that was failed rather than the repair itself). I had
it welded again. Since then I did just a quick 20 minute flight and have found
no. 4 has cracked again, same pattern. So each rear pipe has cracked twice
now. Both front pipes have been ok to date. The cracks do seem to run through
where the spring attachment loops are welded on as my previous picture shows.
As far as I am aware my springs are stainless - as supplied by Europa (they
look stainless to me!). The engine runs very smoothly - as you say it can be
a bit clunky on start/ stop but not excessively. My propeller is a BSW (Bog
Standard
Warp!) ground adjustable 64" non tapered blades warpdrive fitted to my
912 ULS. I always keep the carbs well sync'd. I do notice sometimes a slight
vibration during slowing down and/ or descending - if flying fast at a high
power
setting when I reduce power at high speed, at a certain point during the
power reduction - usually when the throttle has been brought a fair way back a
slight vibration/ resonance can sometimes suddenly kick in but it's only ever
very slight, a slight tremble than an actual vibration. More of a slight change
in sound. I've never thought anything of it. I don't really know where to
go with t!
his now
as it seems to be an ongoing problem I have and I can't really fault anything
else
in my setup.
Cheers, Jon
--------
G-TERN
Classic Mono
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