Retirement Age of a Diesel Engine

[Boracay]

My experience has been that the following are good pointers to an old diesel engine having reached the end of it's useful life:-
* injector pump needs an overhaul.
* water pump">raw water pump needs an overhaul.
* Serious oil consumption with major parts not available.

As many have said it's not the number of hours, it's age, condition and parts cost and availability that matter.

And given the cost of diesel mechanics it's probably better to retire sooner rather than later.

[boatpoker]

Originally Posted by Snore

Boat poker I would like to read that article, but the link does not work. When I googled "new to diesel engines" I could not find that article. Could you provide a link?


+1 for the maintenance. I changed the oils and filter the day I bought Cynosure and change the engine oil and filter every 100 hours. Based on comments in another thread, when I get to the dock I idle the engine for about 10 minutes and run the blower after shut down for 10-15 minutes to cool the engine compartment.

Thanks

Snore, I just tried the link and it worked for me but if it still does not work for you you can just cut'n'paste the website address portcreditmarinesurveys.com

[S/V Alchemy]

Originally Posted by S/V_Surya

I think a diesel is done if you cannot get parts for it. My perkins I think is original, boat is 37 years old. Hour meter shows 270 hours (yeah right). They just need to be rebuilt often. I heard and I believe the worst thing you can do to a diesel is not run it.

That would lead to the second-worst thing being running the diesel from cold to redline for 10 minutes to get to the start line, racing for two hours, and then repeating the same process to get to the bar.

I've seen new Yanmars require overhauls after four or five seasons of that sort of treatment.

Diesels, given clean fuel and regular oil changes, like to be run at 75% or so of maximum (which is often 1800-2200 RPM in the typical 30-80 HP range) and left there for hours. In some ways, the qualities that make diesel a perfect choice for passagemakers and cruisers, who might easily do 10 or more hours of steady motoring to avoid calms, make it the worst choice for racers and day sailers who just want to get out of the basin and head-to-wind.

Diesels don't like short, high-rev runs, in my experience.

[S/V Alchemy]

Originally Posted by Bluewaters2812

True on the parts availability (was that a VW marine engine)??

What are the important spare parts to a marine diesel engine?

All the ones you can buy as issued by the original manufacturer of the block.

A large percentage of "marine" diesels are tractor or car/small van diesels with "marinized" (read: a water cooling circuit of some description instead of a fan and a rad) bolt-on bits.

My new Beta Marine 60 HP is based on a Kubota forklift/little backhoe/small tractor engine. All spares save for things like the heat exchanger I can get by standing in line at the tractor dealership at non-Volvo, non-Yanmar prices.

[Bluewaters2812]

Originally Posted by S/V Alchemy

That would lead to the second-worst thing being running the diesel from cold to redline for 10 minutes to get to the start line, racing for two hours, and then repeating the same process to get to the bar.

I've seen new Yanmars require overhauls after four or five seasons of that sort of treatment.

Diesels, given clean fuel and regular oil changes, like to be run at 75% or so of maximum (which is often 1800-2200 RPM in the typical 30-80 HP range) and left there for hours. In some ways, the qualities that make diesel a perfect choice for passagemakers and cruisers, who might easily do 10 or more hours of steady motoring to avoid calms, make it the worst choice for racers and day sailers who just want to get out of the basin and head-to-wind.

Diesels don't like short, high-rev runs, in my experience.

I subscribe to the notion that diesel engines hate midweek club-racers that fire them up to get them out of the marina to be switched off for an hour or two's sail-racing and then banged back on to get into harbour and moor the boat up only to be switched off again.

Go cruiser/live-aboards ... I am a diesel engine ... use me properly!

[wsmurdoch]

My 1988 Yanmar 3HM35F had 4000 hr on it when I bought the boat in 2004. The boat in the past had suffered damage to the port quarter and had been repaired (hurricane?). The boat has engine drive refrigeration backed up by 125v refrigeration, so the engine has to run an hour a day at anchor or underway to keep the freezer frozen. When in my hands the oil and filter have been changed every 150 hr, the valves set every 300, and the coolant changed yearly. At 6500 hr while motoring through Vero Beach on the ICW the oil consumption jumped from a quart every 50 hr to a quart every 5 to 7. On the suggeston of Anchor Marine in Miami, we bought 10 gal of oil and went to the Bahamas for 5 months. On our return I pulled the engine, drove to Mac Boring in NJ, and had the engine rebuilt. The rings in the aft most cylinder were stuck in the piston (corrosion) explaining the oil usage. The technician quessed that the engine had been underwater at some time. $6131 later the engine was back in the boat and running well.

Bill Murdoch
1988 PSC 34
Irish Eyes
www.irish-eyes-to-the-bahamas.blogspot.com

[David M]

I know of a few Diesels that have been running since WW2 without a rebuild. It's not the age that counts but rather the design, useage and maintenance.

[cal40john]

Originally Posted by carstenb

Bluewater,
On another thread here, some are suggesting that Yanmars should be run at 80-85% of max rpm. This is wrong. Not only is the diesel usage excessive at this speed, but most Yanmars reach maximum torque at around 55-60% of max rpms. This is the correct speed for cruising. The quick way to check this is to sail the boat. When the increasing rpm's start digging the stern deeper into the water, you are stressing the engine. back off a couple of hundred revs and you now have the optimal rpm. optimal rpms will change with boat trim and load.

I think in this case I will follow the instructions in the Yanmar manual over internet advice.

You can run Yanmars at lower rpms than the recommended 80% minimum and follow the manual. They state approximately every 2 hours that you run the rpms up to at least 80% for a few minutes.

[Lojanica]

I used to work on dredges. Mostly smaller units which could be broken down, transported, and reassembled. 100-200hp. The diesels would be run 24 hours, day and night round the clock for weeks and weeks until the oil needed changing. Hours were measured in tens of thousands. Tanks were refueled while running. They'll run forever or so it seems with proper care.

[stevensuf]

Yanmar 4jh3e, 11 years old, 5200 hours when i got it, sitting at 6500 hours and starts /runs no probs, drinks about a litre of oil between changes.

[ranger58sb]

Originally Posted by wsmurdoch

The boat has engine drive refrigeration backed up by 125v refrigeration, so the engine has to run an hour a day at anchor or underway to keep the freezer frozen.

Pardon the tangent...

What is engine driven refrigeration?

-Chris

[Sailmonkey]

Originally Posted by ranger42c

Pardon the tangent...

What is engine driven refrigeration?

-Chris

A compressor mounted on the engine to chill a cold plate. Lookup seafrost.

[ranger58sb]

Originally Posted by Sailmonkey

A compressor mounted on the engine to chill a cold plate. Lookup seafrost.

Thanks. -C

[sailorboy1]

Originally Posted by cal40john

I think in this case I will follow the instructions in the Yanmar manual over internet advice.

You can run Yanmars at lower rpms than the recommended 80% minimum and follow the manual. They state approximately every 2 hours that you run the rpms up to at least 80% for a few minutes.

I agree and run mine the same way!

Hell I don't even know what 80% load on my engine is. I run mine based on sound, it is pretty apparent from the sound where the engine is most happy at. But run it up hard a few times every few hours and allow it it cool down prior to shutting down.

I think that other than operating your engine corrently and changing the oil etc that how long the engine lasts comes down to luck! On my engine the luck line lines up with the 20,000 hour mark I hope.

[Dockhead]

Originally Posted by Bluewaters2812

All very good advice which I will follow thanks. I so agree with the water/diesel filter/separator inline. A good friend had to continually pump out and sort out water contamination on almost a 2 weekly basis because he did not have an inline water separator/filter on his diesel engine on a fresh water river near us (I shudder to think of the sea environment problems). I navigated for him to cross the Solent on the UK East Coast (we did it at night because of time constraints and tides!), yikes, never again!

He was also always very reluctant to allow anything much more than idle the engine and would idle it for long periods thinking he was saving the poor old girl (I think she was a Perkins). I can only imagine the internal sufferings that engine was going through. Just glad she purred across the Solent and the few times we needed her to work hard she did so without missing a beat thank goodness.

That's an unusual problem to have on the UK South Coast. I bet he had an accumulation of water in the bottom of his tank from many years, which finally reached the fuel pickup. The quality of fuel in the UK is extremely high, and I have never drained water from my Racors in more than three years and hundreds of hours of use, never even seen a drop of water in them. BUT -- I had my tank cleaned out when I bought my boat -- the first thing I did! I suggest your friend might do the same.