Just a dumb thought - how many hours do you have on the engine? Perhaps the
engine mounts have compressed and the engine has sagged slightly. 5mm is
not much at all...
Shaun Simpkins
A207
----- Original Message -----
From: <BRYNALL@aol.com>
Subject: Re: Exhaust sytem movement
> To Roger Mills,
>
> Roger,
>
> I recalled what you said to me about exhaust unit securing nuts from when
we
> last met. That was what made me have a closer look at the problem on this
> service. Thanks!
>
> The problem is that the silencer has dropped away from the engine since I
> originally built it? With the XS there is an aluminium sheet metal duct
> fitted under the silencer which ducts cooling air to the underslung Water
and
> oil coolers. We are instructed to engineer a 5mm clearance between the
> silencer and the aluminium. As the silencer has sunk it has taken up this
> clearance. No matter how I try to reconfigure the pipes, the silencer, and
> the nuts I cannot re establish this clearance.
>
> It is almost as though the rear pipes have grown or sagged. I suppose it
is
> possible if the pipes get to be really hot, and the silencer provides
weight
> and a vibratory factor, GS did tell me once that the Exhaust pipes glow
red
> in service. That would be enough for stress relieving movement I quess.
>
> Fortunately I can lower the duct surface by a few mm to recreate the
> clearance, but it would be nice to know how common the problem is, or if
> there are any other thoughts and solutions. Or does carry on growing over
the
> years untill it eventually appears through the bottom of the cowling?:)
>
> Best regards Bryan
>
|