Turbo dock chatter; info needed

[scubadiver535]

My port turbo failed on a layover in Monterey. I was on a buoy ball in Monterey and started the engines every week for two hours to charge the batteries and lubricate the engine. The shaft broke and the scuttlebutt is the engine was not in idle long enough for the turbo to slow down, not getting lubrication thus damaging the shaft. I ran the engines at 1000 rpm's then slowed them to idle before shutting down. The engines were at idle for about 30 seconds before shut down.
Questions - At what rpm does the turbo kick in? How long at idle before shut down? Does the turbo spin after the engine is shut down?

[ksanders]

On the cummins engines you see boost pressure starting to come up at around 1800 RPM.

The turbo doesn’t come off and on, it spins as a result of exhaust gas flowing past the fan blades

[Sportscar]

The turbo spins down after the engine turns off. This is why you don't turn the key off after the engine was running at high RPM. As for what you did, you did exactly the right thing. Engine running at 1000 RPM is hardly anything to worry about and you ran the engine at idle for 30 seconds before turning the engine off is absolutely a good thing to do. Nothing you did should have had any part in your turbo failing.

[scubadiver535]

Glad it wasn't me. Probable just old age. Now to wait for the starboard to go out.