[Codger]

Hi Mark

There are a lot of these questions that it's difficult to get hard data on.
I would hope that a designer/builder would take proper loading in to account but I don't know that for a fact and like any other professions there are probably those that do take it in to full account and others that don't.
Controllable pitch props would help but are there other reliability issues there?
Engine electronics do affect engine efficiency but the electronics themselves are not bullet proof. Diesel Electrics make a lot of sense and on shore there is the example of railway locomotives that have great reliability.
I don't see the manufacturers posting a note in their news sections in the vein of; " we just completed a rebuild on X diesel that was in service for 2900 hours at 3/4 throttle, 225 hours at idle, and the rebuild took 72 hours" or "MV XXX was just hauled in to the yard because the aluminium crankshaft failed disasterously during sea trials and we don't have a clue what to do other than swap in completely different power plants." or "MVXXX is still floating around somewhere off the grand banks without power probably due to a static discharge frying the primary and backup ECUs, by the way we told the engineer not to wear synthetic socks since they are prone to static charges/discharges" Aviation is a whole different world.. anything that goes wrong is open info to the entire industry.

[Mark in SBA]

Codger,

Never did get around to answering your original question. Cat specs the 3616 at 10- to 12,500 hours for the top end, and 20- to 25,000 hours for the bottom end. My guess is these really "big" diesels run with relatively low BMEP, thereby increasing their longevity.

Only 3616 deployment I know of is Limitless.

It's a really big engine!

[DieselJoe]

This is a good question. My reply is mostly for smaller Yachts 100 and below but does apply to "ALL" engines.

Anyhow, Wish I had a few days to reply to this thread. Being a Diesel Engine Survey and mechanic for the past 25 years I have learned mucho and it would take days to honestly reply to engine longevity question.

The main factor and most over looked cause for shortened engine life is engine load, mostly caused by oversized props. Make sure your props are the proper size. The way to check this is run the vessel at full throttle under full load conditions (full fuel, water, personal items, etc.) if your full-load RPM'S are below factory recommendations then re-pitch or re-size your props as needed to allow your engine to run efficiently. Even if you never run your engines at full-load your still overloading your engines at cruse or below with oversized props. Does your transom turn black? Its really simple, overloaded engines burn more fuel which will shorten engine life expectancy. As for engine life, the only sure fire way to determine engine life is how much fuel goes through her. Keep in mind, an overloaded engine burns more fuel then a happy one!

Inactive engine = Not good
Idle your “High Performance” engine at the dock for more the a few min=Not good
Changing your oil at factory recommended intervals, most are around 200 hours= Not good. 100 hours= GOOD!, Oil is cheep insurance.

There are many more factors, these are just a few.

Just my 2 cents which aint worth a penny

[Codger]

Originally Posted by DieselJoe

"Anyhow, Wish I had a few days to reply to this thread. Being a Diesel Engine Survey and mechanic for the past 25 years I have learned mucho and it would take days to honestly reply to engine longevity question."

Have at her.
You don't have to put it all down in one post.
The information from someone that has "been there, done that" would be much appreciated.
Your point on idling diesels is well taken. Just long enough to see the oil pressures come up and fuel pressure stabilise is all it takes. It'll warm up faster under load.

[Capt J]

Originally Posted by Codger

Have at her.
You don't have to put it all down in one post.
The information from someone that has "been there, done that" would be much appreciated.
Your point on idling diesels is well taken. Just long enough to see the oil pressures come up and fuel pressure stabilise is all it takes. It'll warm up faster under load.

You do not want to put a load on a cold diesel. Diesel engines have parts made of different materials that expand at different rates. By putting a load on a cold diesel you are accelerating wear because some parts have expanded and some have not.
As for longevity in the 100< range. Many of the diesels are rated in both hours and fuel consumed. For example the larger C series caterpillers are rated at 10,000 hours and I think it's 40,000 gallons of fuel. The MTU DDEC's are also rated to go a long time. However, I personally know of 4 different boats with 16v2000's that have come apart in less then 500 hours. Man has seen the common rail engines last 30,000 hrs in a steady cruise rpm state on ferry boats. But don't expect that in a normal boat.

[Codger]

Capt J

We've been running everything from large cat gen sets to vehicle diesels perhaps under false information. Start, let the pressures all level out and as soon as temp shows any movement applying light load. No heavy load until normal operating temps achieved. Have we been ill-advised? Or are marine applications a different kettle of fish?
25 year old Cat D9 push cat with 15k+ hours that has been run this way since day one. Suppose I ought to check and see if there's been any work done to the powerplant but I don't recall any painful bills on it. Hydraulics at -40C are another story.


BTW. The man that services these machines is a fanatic so I know that it's been maintained better than what is specified.

[Capt J]

A light load should be ok. It is a little different in a vehicle application and a yacht application. I don't think anyone would advise putting a heavy load on a diesel when it is not at operating temp.

[AMG]

I know that big high performance diesels are also preheated up to 24 hours before startup. Not the preheating you do with the key, prior to starting the diesel, more like when you have cooling water heaters on cars in cold climates.

This prevents the engine to smoke and build up carbon inside and of course it will allow for a shorter period before putting load on the engine.

Perhaps DieselJoe can expand on how the preheating itself is made?