Turning Off Your Diesel Engine

[psneeld]

John...I am thinking the Yanmars were turbos?


If so...I have always heard high speed shut downs were pretty bad for them as the oil pressure dropps off but the turbo is still spinning at high speeds.
Anyone also hear the same?

 

[Steve]

Years ago we used to install Detroit Diesels, GM 53 and 71 series, in Ag. equipment there was a very noticeable detent between low idle and the stop position.

 

[Steve]

John...I am thinking the Yanmars were turbos?


If so...I have always heard high speed shut downs were pretty bad for them as the oil pressure dropps off but the turbo is still spinning at high speeds.
Anyone also hear the same?

I don't know about Yanmar but I remember many machinery operators in the third world for some reason liked to WOT their machines engine then quickly shut it down just to hear the turbo whirring. On Cat engines the service reps always warned against this for the reason you stated, low oil pressure to turbo bearings.

 

[FF]

Turbos have ball bearings so less oil pressure on spin down is not the problem.

Shutting down just after a high load will leave the turbo really hot, this will cook/coke the oil in the lube oil passages which is a problem.

Oil flow can be reduces or blocked over time.

A 2-3 min cool down (idle) is usually enough to shut down after WOT operation.

 

[Ski in NC]

Very few marine diesels have ball bearing turbos. I don't know of any.

If a small engine, even after a rev the little turbo will slow down very quick. Big engine, it can spool for many seconds, probably not good.

Pretty hard to cook a marine turbo after docking. The idling to get in the slip takes care of cooldown.

 

[Salish Nomad]

Dave, I have a Perkins. As stated just a bit before, I shut the key off and the engine continues to run. Assume that is due to a mechanical fuel pump meaning no matter the position, power on or off, once the engine is running it will continue till the fuel is shut off. On our boat that it is the breaking or stopping the fuel supply. As that is an electrical act, one has to assume that the key switch doesn't affect the fuel issue till the physical act of pushing the fuel shut off button.

Am I incorrect? Or just confused?

Al-Ketchikan

I believe you are correct, on my perkins the in th on position provides power to the fuel shut off solenoid. If I switch off the key the engine keeps running, and pressing the stop button has no effect.