What is the useful economic life of a diesel inboard?

[rbw156]

What is the useful economic life of a diesel inboard? Assuming it has been well maintained. When would it need a strip down and rebuild? Are we talking 5,000 hours or 50,000 hours?

[peterb]

I doubt 50,000 hours - but I would guess that its probably at least 10,000 hours.

If you ignore the "marinising" stuff, and refer to the actual engine then really you can draw comparisons of sorts with modern tractor diesel engines and also modern car diesels.

My neighbour is a town taxi driver - presently he has clocked up 400k miles on his diesel car. At an average of 30mph (optimistic?), thats 13,000 hours. Theres not much wrong with the engine - although the rest of the car is wrecked!

If you look on a Tractor Sales site - you will see endless tractors with 10,000 hours on them. Still classed as decent bits of kit and making good money.

I appreciate that the car and tractor engines are probably less "stressed" in terms of power output than their marine counterparts. My marine diesel produces 260hp from 3.7 litres - and there are proposals to take 300hp from the same block.

However, unless you are a complete idiot, you dont run your engine flat out all the time, so this may not be a huge factor in longevity.

Lastly - just to say - a diesel engine of any sort will only give this sort of lifetime if the oil/filters are changed exactly as per manufacturers standards. Old oil = shortened life..........

[jwalker]

Originally Posted by peterb

... a diesel engine of any sort will only give this sort of lifetime if the oil/filters are changed exactly as per manufacturers standards.

Or sooner.

[Searider]

They don't usually wear out - ancilliaries tend to corrode causing problems.

Coolers gradually furr up and if not dealt with can lead to overheating and possible death of the engine.

Age and preventative maintainance rather than hours determine life.

[codprawn]

As peterb says it's how you use it - it's revs that kill a diesel - if you look at the ratings for marine diesels you will see commercial use engines are derated by as much as 50 - 60%!!! Basically this is just a rev limiter - typically dropping the revs from say 2400rpm - 1800rpm.

The longest life diesels are the old plodders - the slow running diesels like Kelvin and Gardner etc - they WILL go on for ever. Modern high speed diesels don't have such an easy life.

A lot also depends on what they are attached to. A water jet is very easy on an engine - the revs tend to stay constant and there are no sudden shock loads.

Lightweight marine diesels are usually adopted car engines and tend to run at quite high speeds for a diesel - whilst they will last a reasonable time they won't still be chugging around in 20 years time unless they are really treated gently - and would you want to do that on a RIB???

[GuyP]

Originally Posted by codprawn

The longest life diesels are the old plodders - the slow running diesels like Kelvin and Gardner etc - they WILL go on for ever.

My uncle has an early 1960's Brit diesel as a bass fishing engine in his Mitchel 23. A real arse to start but once it's up it'll go on forever. I'm amazed it still runs but i guess it's so simple (single cylinder i think - you can actually hear every revolution at low revs) that it's never going to die.

[codprawn]

I suspect it's a Lister - as used in many generators etc. As you say a bitch to start but keep going forever.

You often see old Lister gennys for sale at about £600 - for the same money you can have a nice shiny chinese generator brand new. Many people make the mistake of buying the new one and yet the old Lister will still be around in another 40 years. Mates of mine are from the Gambia and they soon realised that buying a new chinese generator is a false economy!!

[GuyP]

Originally Posted by codprawn

I suspect it's a Lister

no it's actually called a 'Brit' - made by Brit Engineering Ltd.

[codprawn]

Ahh I thought you meant a British diesel - never heard of them!!!

[codprawn]

The power of the net - looks like you have something quite rare. Is it one of TVO engines?

http://www.oldmarineengine.com/discu...454/92145.html

http://www.oldmarineengine.com/discu...es/1/2840.html

[GuyP]

What do you mean by TVO?

it's a hand cranked model (which is why it's an arse to start!) like the picture in your link. It'll literally run at 100 RPM a minute - at those sort of revs you can only hear the air being sucked in and the prop shaft turning - which is why it's great for bass fishing. No sound!

Sorry for high-jacking your thread RBW

[peterb]

TVO = Tractor Vapourising Oil. (basically like paraffin).

In the days of yore (when I was a mere lad) my Dads first few tractors were TVO based. You started them on petrol and let them warm up - then when they were warm you switched to TVO and although you lost a few horsepower, the paraffin was a lot cheaper to buy so it made economic sense.

All Dads tractors that were like this were based on the Ferguson T20 as per wikipedia.

[codprawn]

TVO is tractor vapourising oil - basically paraffin and petrol with 2 stroke oil - used to be used on old tractors etc when diesel wasn't so common. It did say that some of the old Brit engines were TVO which is why I asked.

[Limey Linda]

When I was a kid my father had a friend that owned an old converted fishing boat, about 45 ft. I think it was one of the Little Ships of Dunkirk. You lifted a hatch in the deck, exposing a large flywheel, made sure the de-comp. lever was open and spun the flywheel with your foot, when it was up to speed close the de-comp. and Da-Donk, Da-Donk, Da Donk.................. he used to boast he could cross the Channel on less than 2 gallons of deisel.

[rbw156]

Thanks for all the replies.

So the real old "putt putts" last forever. They also sound great! How about the turbo charged modern marine diesels, like the Volvo KAD44?

[IBWET]

Originally Posted by rbw156

Thanks for all the replies.

So the real old "putt putts" last forever. They also sound great! How about the turbo charged modern marine diesels, like the Volvo KAD44?

I've a little experience with this engine, coupled with these observations from knowledgeable marine engineers (I pump them for info when ever poss )

1) In leisure applications, they die form lack use or lack of maintenance, things that will shorten it's life are;
Turning the key once every two weeks during the winter, bad thing to do if your only keeping it running for a short period of time as all you do is introduce moisture to the wrong bits
2) Always walk the boat up onto the plane, with the throttles as the s/c can shove oil out of the journals at low RPM creating wear.
3) Don’t leave anti freeze more than two years as it become corrosive after that time.
4) Do the entire usual servicing etc regularly.

If you do the above, estimates (no one knows for certain, as far as I'm aware could be wrong) if used every day, oil changed regularly, fishermen suggest ten's of thousands of hours .

[rbw156]

Originally Posted by IBWET

I've a little experience with this engine, coupled with these observations from knowledgeable marine engineers (I pump them for info when ever poss )

1) In leisure applications, they die form lack use or lack of maintenance, things that will shorten it's life are;
Turning the key once every two weeks during the winter, bad thing to do if your only keeping it running for a short period of time as all you do is introduce moisture to the wrong bits
2) Always walk the boat up onto the plane, with the throttles as the s/c can shove oil out of the journals at low RPM creating wear.
3) Don’t leave anti freeze more than two years as it become corrosive after that time.
4) Do the entire usual servicing etc regularly.

If you do the above, estimates (no one knows for certain, as far as I'm aware could be wrong) if used every day, oil changed regularly, fishermen suggest ten's of thousands of hours .

IBWET, thanks for your advice. How should I maintain the engine over the winter period if I only use it occasionally, but for reasonable periods when I do? Also, what does "s/c" mean in your second point?

[IBWET]

Originally Posted by rbw156

IBWET, thanks for your advice. How should I maintain the engine over the winter period if I only use it occasionally, but for reasonable periods when I do? Also, what does "s/c" mean in your second point?

Take the boat for a run,don't just start the engine and leave it for a couple of min ticking over.

S/C - supercharger.

Reading my last post,walking the boat up onto the plane may not be so important for a light rib. This was more for a cruiser weighing 10 tons,which takes it's time getting out of the hole.

watch for black dust;it means a belts on the way out. is your engine EDC ?

remember the air filter if you don't change it, power drops off. Maintenance, It's pretty typical of a car if have done that before.

PM me if you have any issue's I'm no expert but might have come across it.

[rama]

i used to run commercial boats which would average 4 to 5 thousand hours a year, a real bitch when servicing as the engines never cooled down. i had one boat with a perkins m240 ti, 6,354 that must of had around 70,000 hours on it and still ran perfect till the heat ex/ ex manifold cracked and there was not a replacement available. as far as i know it was on its original liners but second set of pistons and bearings,

[seafariskye]

My 1st engine was a KAD 44 EDC

Put 4500 hours on it, after servicing early, and looking after it all its life from new.
Took it for an overhaul, and the price i was given by volvo to do 'all it needed' was about 2 k less than a whole new engine, so i put a new engine in it instead.
Took the issue up with volvo, who then said it was my fault, for using it so much, and not using a main dealer for all its servicing...... argued a bit with them, but got nowhere. think if i remem properly they said that on average a leisure user would clock up about 100 hours per year - so that made my engine 45 years old. At that time, which was 2003, they had not heard of a KAD 44 with so many hours on it.. Oh, and i was told i had also been running it at the wrong revs, so that was my fault as well.

Pete