Hi Todd,

You know when it's time to flip the switch when the turbo is no longer working and you find yourself being restricted to manifold pressures that are consistent with normal aspiration, yet the engine is otherwise running normally.  If you find yourself wanting to flip the switch, you probably already know that the turbo is toast.  Also, as in one of the instances that happened to me, someone on the ground might radio and say that you are 'on fire' because of the large amount of smoke in your exhaust.  If at any point you are in doubt, you can turn sharply and examine your exhaust.  If you seem to be using your uninstalled smoke system, flip the switch.  

Good question though.

Dave Leonard

On Sat, Sep 12, 2020 at 12:36 PM Marc Wiese cardmarc@charter.net <flyrotary@lancaironline.net> wrote:

Most certified aircraft have a check valve (that requires regular maintenance) in the return line.

Marc

 

From: Rotary motors in aircraft
Sent: Saturday, September 12, 2020 4:13 AM
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: [FlyRotary] Turbo oil cut-off valve

 

Hi Dave;

  Today I installed a small normally open solenoid valve on my turbo oil supply line. An AME that happened by was questioning how exactly that I would know that my turbo bearings were failed and loosing oil. I couldn't give him an answer that he was satisfied with and he now has me questioning whether I would know with a reasonable degree of certainty.

  So exactly what did your turbo do when it failed that made you certain of what it was.

  I figure that if I got it wrong and cut off oil when it was still working, then worst case is that I just destroy $1AMU turbo, but most likely it would just destroy the bearings.

 

Todd