The Mythical 20,000 Hour Engine??

I'd like to get some experienced users' insights into engine life. I've been searching for a bluewater trawler for over 6 months. I have run into a quandary regarding engine life. Starting with the understanding that if the engine is maintained properly, it will last a significant number of hours. However, not everyone does this. In dealing with brokers, I routinely hear that the Caterpillar, Cummins, Lugger, etc. are all easily 20,000 + hour engines. Most hours I've ever seen on the used boat market have less than 6,000 hours. Where are all the boats with 10,000 plus hours?? We have posed this question to a few brokers and don't really get a response. What are your thoughts? I'm a newbie, go easy on me. Thanks in advance.

Well my 3208 has about 11000 hrs it 20yr old

All the boats with 10,000+ hours are in the commercial fishing and working fleet. They get started up at the beginning of a trip and get shut down a month or two later when they get home. 1800rpm gensets with 4 and 6 cyl diesels can get astronomical hours (by pleasure boat standards) if maintained. Another factor is that many if not most commercial diesels are propped and rated at lower hp/rpm levels than the same engine in a pleasure craft.

At an above average recreational use of 200 hours/year, 20,000 hours is 100 years.

Greetings,
Welcome aboard. I know of only one recreational "trawler" that purported to have 20k hours on the original Ford Lehman diesel (single engine). The folks that told me this were 6000 hours on their re-power. I can't remember what they replaced the Lehman with. I really don't think they had any reason to lie to me.

The boat my boss just sold had 2 gens, powered by Cummins 6BT's, basically a marinized version of a Dodge Ram truck engine. I do oil changes at 250 hrs, injectors anywhere from 1200-1500 hrs depending on our travel schedule. The gens were still running almost trouble free with 14,000 hours EACH when we sold her.

The buyers survey showed they still pulled full load and ran strong without overheating even in 85 degree So Fla waters.

As noted above, two things limit the number of 20,000 hour recreational boat engines on the market:

1. Very few recreational boats run enough hours to get to 20,000.

2. The engine isn't maintained or operated well and it fails and must be repowered.

Virtually every recreational boat engine has the potential of getting to 20,000 hours if maintained and operated right.

David

I agree with WH re commercial use. Start a diesel and let it run under load. Just think of Grey Hound Bus or construction/mining equipment. We pleasure users would have to run a boat 41 24 hr days to put 1000 hrs on. But as a buyer looking for a boat two things re engines have come to light. First off the 20 yr boat with low hrs. something around 1000 to 1500. That is 50 to 75 hrs the latter figure being the exception. Then the "I start the boat engine every Sunday" boater. Same boat but lower hrs. Yes he brings it up to temp, but never loads, runs the engine for 30 minutes or so. The engine has extensive carbon issues and has a very short life. Ever wonder why sail boats seem to have so much engine trouble? The sail engine goes from dock to sail raise back from sail down to the dock. Never or hardly ever has any load over time. The other issue relates to I never go to WOT or even to 80% I just cruise at 5-7kts. Once again the engine is never loaded as it should be to get rid of the carbon developed. The same applies to the genny's of this world. Unless they are loaded to at least 75% of capacity they never burn off the carbon and have a short life. They spend their time keeping the beer warm and bty charging. Another subject re genny's most boats have too much capacity unless you run the AC or heat all the time. Care and proper service of pleasure craft engines usually takes a back seat. Check out Pascal's article on diesel engines. PS there are gasoline 454s with over 8000 hrs still working perfectly. Secret is maintenance: Oil and anti-freeze regular changes and being properly propped.

BerettaRacer said:

The boat my boss just sold had 2 gens, powered by Cummins 6BT's, basically a marinized version of a Dodge Ram truck engine. I do oil changes at 250 hrs, injectors anywhere from 1200-1500 hrs depending on our travel schedule. The gens were still running almost trouble free with 14,000 hours EACH when we sold her.

The buyers survey showed they still pulled full load and ran strong without overheating even in 85 degree So Fla waters.

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The original 6BT 210 HP has been around a long time in boats, before they went into Dodge pickups. Was a very common replacement in the early '80s
for Chesapeake Bay waterman who were pulling 350 Chevy engines out and going to diesel. Lots of those went well past 20,000 hours. It's not difficult to rack up 1,500+ hours per year crabbing and oystering.

Ted

We've got two cats with 32000+/- hrs in the research vessel i work on. I think it's the 2 nd or 3rd rebuild (each).

Our mainship only has 2400 hours....

re % load and carbon fouling vs good maintenance. In my experience % load is not nearly as important as proper maintenance on relatively modern 4 stroke diesels.

Case in point. Two identical gen sets installed 1995. Isuzu 4BD1 diesels spinning 50 KVA electric ends at 1800 RPM. Both well over 20,000 hrs. Both get oil / filter changes at 250 hrs, Chevron Delo 400.

Gen #1 works at 30% - 75% load 12 hrs per day. Repairs have been two sets of injectors, two water pumps. Starts right up, runs well, no exhaust smoke, oil samples look good. Oil turns black within a few hrs after an oil change. The front oil seal is beginning to weep.

Gen #2 works at 20% - 30% load 12 hrs per day. Repairs have been one water pump. Starts right up, runs well, no exhaust smoke, oil samples look good. Oil takes over 150 hrs to turn black.

Of course both sets have had minor wear and tear maintenance and repairs. Thermostats, coolant hoses, belts etc.

Since both are in excellent shape it would appear based only on how long it takes the oil to turn black Gen #1, the harder working set, is producing more carbon. Carbon is what turns the oil black.

I think the idea that we need to run 'em hard and hot is a hold over from the older days, especially the two stroke engines.

I'm wondering how much of a negative effect wet exhaust is on engine life? Both of these gen sets are typical work boat dry stack. Very well laid out with no way for rain water to get into the exhaust manifold when the boat is not in use.

Not trying to hijack the thread, but.

Gabe n Em

....in the research vessel i work on.

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Would that be the R/V Savannah? I was on the R/V Clifford A. Barnes from 1983 full time until 2013, ran her part time till her retirement last week. We purchased the Scottish built fisheries R/V Aora in August and are putting her into service for oceanographic research this coming April under her new name Rachel Carson.

At my old job we had 5 Cummings diesels that all had 30,000 plus on them before we rebuilt them. All were running fine but the timing was good for the rebuilds. This was not in a pleasure boat. My neighbour commercial fishes here in Alaska. His main is a 3-71. He has over 90,000 hours on the block. He has put 6,000 hours a year on it for the past 15 years. Takes it down for rebuild every 5 years. His mechanic told him the last rebuild was the last one as the block would be shot when next rebuild is due. All in all not bad service out of an old Detroit.

Portage_Bay said:

Not trying to hijack the thread, but.

Gabe n Em Would that be the R/V Savannah? I was on the R/V Clifford A. Barnes from 1983 full time until 2013, ran her part time till her retirement last week. We purchased the Scottish built fisheries R/V Aora in August and are putting her into service for oceanographic research this coming April under her new name Rachel Carson.

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Sure would! They let me play on a few others from time to time, but the savannah gets the bulk of my time. -Gabe.

"Just think of Grey Hound Bus or construction/mining equipment."

When running the DD 8v71 Hound would exchange the engines annually.

This was about 200,000 miles for the longest routed coaches.

The swop was done overnight , mostly finished before midnight with the air cond drive taking the most time.

This is only about 4,000 hours (nothing for an 8V) but Hound wanted extreme reliability and the ability to never damage the engines , so they could be overhauled almost endlessly.

These were Hound set to 1600RPM , but most were tweaked to 1800.

What everyone already said, and
let's say you are a rec boat owner who did use your boat a lot over 25 years.
If it's a well maintained boat, high engine hours would be the only thing in the way of a good resale value.
Better to re-power, not because it needs it, but because it sells better.

Wxx3 said:

What everyone already said, and
let's say you are a rec boat owner who did use your boat a lot over 25 years.
If it's a well maintained boat, high engine hours would be the only thing in the way of a good resale value.
Better to re-power, not because it needs it, but because it sells better.

Click to expand...

Hmmm! I will bet that you will never get anywhere near the cost of a repower back when you sell.

Take the case of an early 80s KK 42 with a 10,000 hour Lehman that starts reasonably well, uses a little oil but not serious. Compare what you can get for that boat vs the same boat with a completely new engine.

The cost of repowering, say with a remanned Cummins 6BT 210 engine will be about $25K for the engine and at least $10,000 in labor, engine mounts, exhaust system, etc.

Will you get $35,000 more for that boat with the new engine?

David

djmarchand said:

The cost of repowering, say with a remanned Cummins 6BT 210 engine will be about $25K for the engine and at least $10,000 in labor, engine mounts, exhaust system, etc.

Will you get $35,000 more for that boat with the new engine?
David

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David, I'd say Richard is correct. And maybe more given the ongoing popularity of the KK 42. Couple that newer engine with an ER refresh and incidental update of other bits and pieces and the vessel would sell at a premium and very quickly. Especially when one looks at the price of a new KK44.

Not to mention the pleasure the owner would get from said vessel for the remaining or ongoing ownership time. I've seen a few KK42s mentioned here that have modernized and then sold for premium prices. A few years ago I was on Jim Cave's KK42, the redone ER is stunning even though the trusty well tended Lehman has not been pulled.

Some other "timeless" vessel brands come to mind in this regard, if well done. But not all. I'll not get into brands lest some major thread drift.

Wxx3 said:

What everyone already said, and
let's say you are a rec boat owner who did use your boat a lot over 25 years.
If it's a well maintained boat, high engine hours would be the only thing in the way of a good resale value.
Better to re-power, not because it needs it, but because it sells better.

Click to expand...

Hi,

Unfortunately this is the case, although I'm worried about engines with just a few hours and a lot of age.

I wonder if the engines have been serviced according to the instructions, when hours are counted only 20 a year. A lot of hours on the engine well maintained, apparently a better choice.

NBs

djmarchand said:

Hmmm! I will bet that you will never get anywhere near the cost of a repower back when you sell.

Take the case of an early 80s KK 42 with a 10,000 hour Lehman that starts reasonably well, uses a little oil but not serious. Compare what you can get for that boat vs the same boat with a completely new engine.

The cost of repowering, say with a remanned Cummins 6BT 210 engine will be about $25K for the engine and at least $10,000 in labor, engine mounts, exhaust system, etc.

Will you get $35,000 more for that boat with the new engine?

David

Click to expand...

I think it depends on the boat - you can't generalize it to all boats. You wouldn't get that back in a Bayliner or Mainship (nothing wrong with these boats! ), but you might get it in a KK, Nordhavn, or similar.

Blue Sky has a Lugger (Komatsu block) with just under 12000 hours. When we purchased her five years ago she was just over 10,000 so we gave her a significant service but didn`t go inside. Everything (including oil analysis) indicated that she would go another 10,000 with no problem. She now gets serviced Oil change etc.) annually which is about 120-150 hours.

We don`t know her service history although she spent her formative years in Alaska in charter as Eight Stars, which would presumably explain her relatively high hours.

We are very confident that the Lugger will still be going strong long after we pass her on to the next owner, which won`t be for many years to come.

I have a 1963 Lister Blackstone with almost 30,000 hours and I'm putting a Lister Petter Alpha in my current project that I expect the same out of. It's maintenance that keeps an engine going, oil, filters, adjustments, hoses, belts and cleanliness before things start to break.

As I've said before here, the Deutz last engine I overhauled (back when I was 19) ran for another 50,000 hours pulling an irrigation pump. It can be done. Change the oils and filters regularly, and don't get any electronics to fail... This was a 5 cylinder Deutz FL5912 and the design was very similar to a lycoming engine, with iron cylinder sleeves and a turbine blowing cooling air past an oil cooler and through the fins of each cylinder sleeves.

FLx912 and 913 were similar designs except the 913 had a little higher compression. All have bosch mechanical injection pumps which run forever.

These are the same company and design that built the engines that ran in the German Tiger tank back in WWII.

The USCG used to use aircooled Listers on lighted bouys, I've heard accounts of over 100,000 hrs before a rebuild. It is possible with good maintenance and clean fresh fuel.

As pointed out to me ....

http://www.alanhamby.com/maybach.shtml

The Maybach company, under the technical leadership of Karl Maybach, produced the engines for all the medium and heavy German tanks of WWII.

There are a million ways for engines to die way before "their time".

Intermittent type of use and marine age is what is killing most diesels prematurely in pleasure boats. The mythical hours gen-sets and commercial users achieve are not realistic in typical pleasure use.

When you shut down a diesel for a long period (say over winter), some valves will be open and moist air will be rusting those cylinders. Upon start up in the spring there is a good chance some of the rings are stuck and will break if there is enough rust in the cylinder.

Seawater cooled after-coolers are another Achilles heel of high performance diesels. Sooner or later a leak will develop and seawater will enter the engine.

Marginal exhaust geometry and inevitable shower head corrosion that leads to sea water leaks into the engine is another killer.

Most planing boats are over-propped and the engines cannot reach WOT RPMs after the owner has added all his "stuff" to the boat. This will significantly shorten engine life.

Pleasure boat horsepower ratings are just that. These engines are run at the ragged edge but at 100-200 hours per year they will typically last 10 years.

So what can we do? Make sure the engines are not overloaded and run high-strung engines at 70% or below, check your aftercoolers and exhaust showerheads on a yearly basis and always use a block heater when not using regularly.

Hi,


I hope I have this kind of mysterious diesel my CM qsb, the time seems to be half of it.


NBs

psneeld said:

As pointed out to me ....

Tiger I Information Center - The Maybach Engine

The Maybach company, under the technical leadership of Karl Maybach, produced the engines for all the medium and heavy German tanks of WWII.

Click to expand...

That's odd, since Deutz training classes made a big deal about the Deutz - Tiger tank connection...

Also, the reason I overhauled the engine in the first place is the exhaust stack flapper had stuck open and let water into two of the cylinders. We replaced the two sleeves, honed everything back to factory specs and re-assembled it. That was at 1200 or so hours time. It ran for over 50,000 when the owner contacted my father and requested he overhaul it again... Dad laughed at him and said buy another!

Thanks for the correction!

The main factor in long life is the work the engine was designed to do. The 2nd most important factor is how the PO's used them and does the engine have a turbo. There is a huge difference between recreational and commercial engines. Many small engines made for recreational use are just a redesigned gas engine. Most aren't expected to be rebuilt, just replaced. The manufacturers goal, from what I can see, is to make it thru warranty.
Poor maintenance (dirty oil), high exhaust gas temperatures, and running wide open are the engine killers.
Commercial engines are made to be rebuilt. They are bigger and heavier. Things like better materials to withstand greater temperatures and replaceable sleeves so a like factory new bore can be achieved when overhauled.
My Detroit Diesels naturals (actually Gray Marine before the name change) were made in 1947. In contacting the PO's I could document 20,000+ hours to about 1972. In rebuilding myself, numbers on the old sleeves indicated the engines had never been overhauled. PO's had routinely run the engines at 1800 to 2100 rpm. I usually run at 1800, their max hp rating. But because they're heavy duty engines the PO's excessive rpms didn't seem to harm them. You can't do that with a recreational engine. My DDs were one of the main reasons I bought my current boat. They'll probably need overhaul again about 2085, but I won't have to do it.

I ran a large fleet (over 200) of Caterpillar 3516 generators in a former job. We ran them very hard, with normal load over 1000 kW.
In most cases, we did top end overhauls @ about 25,000 and bottom end at 50,000 hours. Oil changes were done at 900-1000 hours.

One of the biggest variable affecting the engine life was the number of startups. The engines that ran during peak hours only, and shut down during the night had a much shorter lifespan than those running almost constantly.