Tired engine...

ERO83

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With obvious factors considered such as the rpm the engine was primarily run at, load, yada yada...what do you all generally consider the tired point for the various common marine diesels. I feel around 10K you're basically on the verge of a rebuild...wrong? I feel like you could definitely get more years out of one but how many. I'm in the used boat market and considering my options price wise but if a rebuild is looming than it's all for not in some ways...I wish I could afford to buy "the right boat" I'm not afraid to do the work on the boat but I just get so many mixed reviews in terms of engine life that I figured I'd throw it out on here and try and gain a little more perspective.
 
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offshore31

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sorry, there's no x hr's or age answer. it's totally driven by how it was maintained, if it was overheated, if it was over propped, how much fuel went through it, and how much hp its putting out. i've seen diesel's with < 2k hrs needing total rebuilds, and others with > 10k hours still running. not at 100% but still going.

if you're nervous, you should get a good diesel mech to do a thorough survey. spend the money, don't be afraid to even do a compression check, although that doesn't tell you everything. with the right instruments, they can tell you that it's got life left in it, or you should rebuild it soon.

good luck
 

Blitzen

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Lets assume the engine is maintained properly, most engine manufactures will rate engine life based on the amount of fuel consumed. The engine is only going to burn so much fuel before a rebuild or replacement. So burn the fuel fast or burn it slow your hours can vary dramatically before it is done.
Also keeping an accurate log of hours and fuel consumed can help determine how the engine was run and remaining life.

On the new electronic engines the ECM maintains a log of Idle fuel and hours and average load so life and maintenance can be tracked.

Different types of boat may see totally different hours based on use.
A lobster boat may have many many hours of idle time and just a few of cruise hours.
A tuna boat may see a balance between idle and cruise hours.
A true cruiser, most likely will have most hours at cruise and just a few at idle.
 

F/V First Team

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And pleasure boaters measure fuel consumption in how many martinis they've consumed because if they have more than 20 hours a year on their boat they've just been charging the battery since they don't have shore power.
 

Toolate

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I logged 2800 hours of martini drinking last year- what do you think of that?

To me, any engine over 1000 hrs needs a serious look. Sure many are in great shape but like you said (not sure who), a couple overheats could spell very bad things right around the corner and who knows what else might have happened in those 1000 hrs.

Not sure you can put an hr # on it. Just your comfort level is all.

This is, to me, the toughest issue to come to grips with when looking for a new boat because a repower could cost more than some boats or at the very least 25% of the value. Big bux either way.

There is a lot of talk about how many hours a diesel will go and I have learned that it is true but how comfortable would any of you 5000 hour guys be inheriting someone else's 5000 hr engine. Just saying. .
 

offshore31

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my first diesel boat had twin cummins with 1650 hrs, and i put another 800sh on them before selling it. except for replacing the starters, they ran great.

i purchased my current boat with 5000+ on her. only 1 season on her, but she's running good. like i said, it's how the boat was run, how it was maintained, if it overheated, and how much fuel went through it. i'm more leary of a sport boat (esp a tuna sport) with lower hours than a stick or lobster boat. the sport boats run hard to beat everyone out. stop, sit and chunk, then start the engine and chase the fish banging in/out of gear. a lobster boat starts the engine and just runs it. where the lobster boat could be an issue is if its idling too much. the engine can cool down too much which can also cause problems. but i'd still rather have one that's run smooth and consistent, rather than ridden hard and put away wet.

and my first diesel was a deep v tuna sport boat, run by a well known capt. so she had been ridden hard, but the owner/capt was beyond meticulous so i wasn't afraid of the hours. i only sold it because the deep v sucked on the hook. my current boat is a 32 bhm which sits like a duck, and has 5k+ hours and i'm looking forward to many more.
 

petrel

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1000 hours? Depends. I bought a boat w/ 671TIs that had over 12,000 hours on them. I had my mechanics install new risers and rework the heads and I ran one for another two years and one for another three (pushing 15,000 hours). They were both running when they got major overhauls. One now has over 4000 hours an the other about 5000. These are turbos, not naturals, but we don't run the piss out of them. Got another boat that had a Cummins 6BTA 315hp version. Somehow that engine was fucked when I got it, and had less than 2000 hours when we replaced it- running but clapped out. Failure of the previous owner to service cooling and fuel injection systems can drastically shorten engine life. With the cost of new engines these days, money spent on preventative maintenance is money well spent.
 

Toolate

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What would make me feel good about a high hr engine is a warrantee from the seller. At least it would make you feel like he was confident and not hiding anything.
 

Blitzen

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What would make me feel good about a high hr engine is a warrantee from the seller. At least it would make you feel like he was confident and not hiding anything.

You know that is not going to work.
 

petrel

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I was going to elaborate on why it would not work, but there is no point. That is all that needs to be said. Thanks.
 

jwalka51

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A good diesel engine isnt even broken in at 5000 hours. Now if we are talking about a yanmar ar a styr or any one of those high revving, low displacement, high out put engines then forget about it. It surprises me that those engines even make it 5000 hours.


If I were buying a lobster boat from someone who had owned the boat and fished it for 5000 hours, with a cummins, John Deere, or detroit in it, then I would expect to get another 10,000 hours out of it at least.
I just did some work on a friends boat the other day who has a 650 mack with 26,000 hours then watched him cold start it at 8 degrees. Another guy I know has a 375 John Deere with 12,000 hours on it, I know another guy with a 210 cummins with 11,000 hours. And another guy has a 226 isuzu with 20,000 hours. All of these engines that I just mentioned are in lobster boats and they run reliably every day.

My own engine had 16,000 on it before it was re-built. And thats because it sank.

So as far as that 5000 hours goes, I would'nt blink at 5000 hours on a commercial grade engine so long as there is no evidence of damage.
 

FPTMarineDiesel

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With obvious factors considered such as the rpm the engine was primarily run at, load, yada yada...what do you all generally consider the tired point for the various common marine diesels. I feel around 10K you're basically on the verge of a rebuild...wrong? I feel like you could definitely get more years out of one but how many. I'm in the used boat market and considering my options price wise but if a rebuild is looming than it's all for not in some ways...I wish I could afford to buy "the right boat" I'm not afraid to do the work on the boat but I just get so many mixed reviews in terms of engine life that I figured I'd throw it out on here and try and gain a little more perspective.
The best way to determine a tired engine as an owner is the following:

1- Does it use oil, there is an acceptable allowable amount of oil consumption to fuel consumption for every diesel engine manufacturer out there, so based off of your model and make, the engine manufacturer can provide this for you to compare against.
2- Does the engine have a lot of oil leaks due to high crankcase pressure, high crankcase pressure is usually a good indication of the following.
a. worn cylinders and piston rings or ring lands
b. worn valve guides and seals
c. turbo charger seal leakage
3- Does the engine start hard, does it crank over longer before firing and when it does, does it stumble and misfire for a few moments while blowing a lot of smoke all over the harbor until it builds a little heat to increase compression? When under way does it knock and stumble a little until fully up to temperature?
4- Does it start only with Ether in cold weather, does it need ether in warm weather? Low compression worn out engine will cause this.
5- Does it not make all of the rated engine speed that it did when new? Does it smoke blue smoke when loaded at higher engine speeds constantly?
6- Is it plugging or fouling oil and oil filters, does oil pressure fluctuate when hot and when cold? High soot content is an indication of carbon and combustion gas leaking by the piston rings and the oil is encapsulating the soot and gases causing early oil breakdown and heavy soot retention. Oil sample is a great tool for understanding engine life. I recommend if you are concerned to start with oil analysis, do it over the period of 3 oil changes to get a trend and a baseline. Take a sample of the oil you use when new to start and than you have a base engine sample and the additive package to compare against the oil breakdown and metallic wear that the oil and filter are trapping along with soot, coolant or fuel.

Just my 2 cents as Bill D would say FWIW.


These are basic symptoms of an engine that is really showing age.

Peter
 

Toolate

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In automotive terms, 10000 hrs is only 600,000 highway miles. Thats all. Just playing devils advocate.
 

FPTMarineDiesel

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In automotive terms, 10000 hrs is only 600,000 highway miles. Thats all. Just playing devils advocate.
We used to use an avg. of 45 Mph unless the vehicle was purely coast to coast for that calculation so more like 450,000 miles. Then mission profile plays a larger role for load factor as to the fuel cosp. curve and life between overhaul.
 
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