What would you consider to be high engine hours?

[CX54WEK]

I dont think engine hours would be too much of a worry for us. It would come down to overall boat condition, service history, maintenance schedule etc.

Obviously lower engine hours are a bonus, but we would take the view that a well used but well maintained boat is a better option than a little used unloved example.

 

[poltergeist]

Just trying to gain an idea of what people would generally consider to be high engine hours.
I realise that decent, regular servicing & age are also important considerations, but if you were to look at a potential boat for sale, what kind of engine hour figure would be the threshold whereby you would look for something else?

 

[poltergeist]

Thats strange - your answer has appeared before I posted the question? ! Your post @16.23, my original question @ 16.24.

 

[CX54WEK]

How bizarre

 

[silver-fox]

Thats strange - your answer has appeared before I posted the question? ! Your post @16.23, my original question @ 16.24.

I have observed that bug in the forum a few times -so don't worry no-one has got the ability to read your mind

Turning to engine hours .

As many marine engines are derivatives of automotive engines the following may hold true or at least set engine hours in anevery day context!

I found that the trip computer on my car was consistently telling me that over a thousand miles or so I was averaging around 30 miles in the hour.

Doing a rough extrapolation of that would mean a 1000 mile = 33 hours of use approx. I think that a minimum of 150,000 miles out of a road engine these days is quite a modest expectation, so I would expect a minimum engine life before a amjor overhaul of 150 x 33 = 4950 hours.

I have friends that have run up 250,000 miles with road diesels which using the same conversion would equate to 8250 hours.

But of course the marine engine has a different life to an automotive engine. It wont be stressed to the the same extent, but it will be subject to harsher corrosive environment and possibly many hours running without sufficient load which can lead to bore glazing.

I suspect more engines die of neglect/poor maintenance or rust than ever wear out!

My engine is 20 years old and running like it was made yesterday. Cant confirm the engine hours though!

 

[rafiki_]

The Siver Fox has done a sensible calc for a car derived engine. These are generally lifed at 150 to 200,000 miles.

Truck engines will be lifed for twice this, so the 5 litre and bigger engines can expect a longer life.

Actually, engine life is a function of duty cycle, so if you use the engine at the top of its performance curve, it will wear out quicker as the duty cycle is higher. Obviously maintenance is another critical factor. Underused and poorly maintained engines will be the biggest problem despite engine hours.

With my boat, one engine was changed at 330 hours, due to overheating as the heat exchanger was clogged with mud. In theory, this was before the engine was run-in, at 400 hours!

 

[crazy4557]

But of course the marine engine has a different life to an automotive engine. It wont be stressed to the the same extent, but it will be subject to harsher corrosive environment and possibly many hours running without sufficient load which can lead to bore glazing.


Sorry, but can't agree with your statement about engine stressing....a marine engine works hard from the minute you cast off to the minute you tie up again. At no time, realistically do boat engines work on a 'trailing throttle or coasting basis like a car coasting down a hill. Always, they are pushing a big lump through the water and this takes an enormous amount of effort from the engine/drive system. IMHO marine engines have a much tougher life and maintenance history is far more important than engine hours.

 

[poltergeist]

I guess on the flip side of that, marine engines don't endure the labours of stop starting (as in a car in town for instance). They would be in the water bourne equivalant of a motorway, constant load, abeit far harsher conditions.

My take is that marine engines get a harder life though, due to the environment they operate in,

 

[kcrane]

Marine diesels are pampered surely, in their separate heated and ventilated engine rooms. Car engines are open to the elements, including being sprayed with more salty water (think last few weeks) than most marine diesels would normally deal with. The environment in which they float is harsh, but they're just looking out of the window at it.

 

[rafiki_]

I think the duty cycle of the average truck is pretty onerous. Pulling 20 to 44 tonnes? I am not aware that many boats go flat out everywhere, and generally trickle in and out of Marina's giving the turbo's a much better chance of warming up and cooling down then most vehicle applications, and also work in a much broader temperature band, being air cooled with ambients from -10 to plus 35 C typically. Water typically ranges from +5 to +20C at the extremes.

 

[hlb]

Marine diesels are pampered surely, in their separate heated and ventilated engine rooms. Car engines are open to the elements, including being sprayed with more salty water (think last few weeks) than most marine diesels would normally deal with. The environment in which they float is harsh, but they're just looking out of the window at it.

Your forgetting boats have salt water in their engines, plus electrolysis. Having said that, the secret to long engine life, is to do it quickly. Hence a five year old truck might well have done half a million miles.

Having said all that, my engines have done 1,800 hours over 21 years. They show no sign of wear. But yes the auxilary stuff has been replaced/mended a few times.

 

[MapisM]

what kind of engine hour figure would be the threshold whereby you would look for something else?

On a "normal" pleasure boat, practically none.
I mean, not the hours per se, unless we're talking about very old boats maybe (20+ years).
It's not the number of hours which can kill a pleasure boat diesel engine.

 

[henkmeuzelaar]

The most relevant single measure of diesel engine age appears to be total revolutions ; i.e. rpm x min.

Whether looking at a giant marine diesel engine running at 200 rpm or a small engine running at 3600 rpm, the total number of rotations that engine is going to be good for (with good maintenance, etc) turns out to be somewhere in the 2-3 billion range.

Interestingly, a very similar total number of 2-3 billion revolutions can be calculated for most gasoline-driven internal combustion engines.

Now for the kicker: the healthy human heart is also capable of about 2-3 billion cycles.....!

Have fun

Flying Dutchman

 

[oldgit]

"Having said all that, my engines have done 1,800 hours over 21 years. They show no sign of wear. But yes the auxilary stuff has been replaced/mended a few times."


Mine are 3200 hours on a 30 year old boat and as with Haydens donkeys the engines are as tough as ye olde boots and still running at reccommended Ts & Ps ,its the other blimming bits(starters/alternators etc) that keep on dropping off.

However,suspect the more highly stressed the engine,ie.newer,the shorter the time between major rebuilds.
The sheer number of old Perkins/Fords still soldiering on and being rebuilt for the umpteenth time are testament to the longevity of a diesel engine just so long as you change its fluids and keep it at the sort of temperatures it likes.

 

[Thepipdoc]

Interstingly, I was told by a boat broker that my twin engined 4.3l Mercruiser boat that's done a "whopping" 400 hours, that it nearly at the end of its life!
The boat has an impecable service history, is only 12 years old and so far has not given me any problems.
Yet the boat he was trying to sell me had done 350 hours and he described his boat as having just been run in!
Strange but true!

 

[stelican]

I dont think engine hours would be too much of a worry for us. It would come down to overall boat condition, service history, maintenance schedule etc.

Obviously lower engine hours are a bonus, but we would take the view that a well used but well maintained boat is a better option than a little used unloved example.

About 90 hours a year seems the average.All systems need regular use to prevent problems

 

[ulyden]

The most relevant single measure of diesel engine age appears to be total revolutions ; i.e. rpm x min.

Whether looking at a giant marine diesel engine running at 200 rpm or a small engine running at 3600 rpm, the total number of rotations that engine is going to be good for (with good maintenance, etc) turns out to be somewhere in the 2-3 billion range.

Interestingly, a very similar total number of 2-3 billion revolutions can be calculated for most gasoline-driven internal combustion engines.

Now for the kicker: the healthy human heart is also capable of about 2-3 billion cycles.....!

Have fun

Flying Dutchman

Interesting! I’m working with engines that typical runs 6-8500houors pr year!
They are doing 12 to 15 revs pr second! That means 65 000h on a 750rpm engine! This is 10years of operation. On a 1500rev engine this is 33 000running hour! I know engines that do 48 000 before piston overhaul!
What about two strokes?

Just remember that the piston speed is more or less constant on all engines.
If you take an average on 10m/s this means that the piston has made 2.4 million kilometres in that time! This is the same even if the speed is 3000 or 100rpm!

Basically I mean that if you look at the total fuel consumption is a good measure! It tells how much work the engine has done!

 

[CX54WEK]

About 90 hours a year seems the average.All systems need regular use to prevent problems

Is that all!!!!!

Maybe we should look at wasy of reducing our useage (around 300 hours a year) instead of increasing it

 

[Divemaster1]

What about two strokes?

Running two seven litre, two stroke Detroit Diesels (6/71 TI) from early 80's with 2000 hrs on the clock...

Consider them as being close to be run in... sweet, smooth and nice exhaust note....
Running between 12 - 1900 RPM over longer durations.(2 - 10 hrs)... and very seldom at WOT (2300). No problems with engines, but one waterpump and one alternator changed (from the originals) over the last 500 hrs...

 

[ulyden]

The sound of these engines is really confusing. One man I know bought a small ship that was destroyed in Bergen during a storm. (Oil platform nearly hitting the puddefjord bridge.) This boat was bent and he was planning to use the engine. It was a two stroke Detroit!
One time he was moving the boat, I was listening! Very hi speed for idling, hmm! When he started moving i thought he was crazy. Then he increased the speed even more! Maniac! Then I remember that he had a two stroke engine! Sound from two strokes always fouls me. But the engine had between 20 and 30 000 hours and good as new! 2000hours is close to nothing!

I have also problems with Wichmann engines in ferries! Always think they are overspending!
But I have been overhauling Wichmann engines. Last forever!

I have been working with large 4 stroke engines for 20years and I’m very sensitive for sounds.(May be the reason for the nick) I use only one type of air bells!

I’m not very good in english. Is there a good word for: ulyd?