Engine longevity.

fisherman

fisherman

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Often people here ask about whether it's wise to buy a boat that has even a few hundred hours on the engine. A fishing boat near me has had the engine, Ford Dover 6 cyl nat asp, replaced, it had 42000 hours on the clock.....which stopped working a while back. There was no issue with it, start/go/no smoke no excessive oil useage, the new owner just wanted a new engine. I think he now has one with lots of electric management.........
 
fisherman said:
Often people here ask about whether it's wise to buy a boat that has even a few hundred hours on the engine. A fishing boat near me has had the engine, Ford Dover 6 cyl nat asp, replaced, it had 42000 hours on the clock.....which stopped working a while back. There was no issue with it, start/go/no smoke no excessive oil useage, the new owner just wanted a new engine. I think he now has one with lots of electric management.........
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What a fool. It was just about run-in :) Seriously 42k Hrs is nothing if shes looked after.
My Ford 2712e is 40 yrs old so what? runs sweet as a bell & no electrics to go wrong.
 
I'd rather buy a well used engine, than a poorly stored engine!!

The "need for speed" and reaching the illusive 30 knot mark and demand for domestic space drove engine manufacturers towards weight reduction, turbochargers, intercoolers, compressors, higher RPM and basically taking out more HP per volume unit ... (Volvo TAMD40 @ 130 HP, which eventually evolved to the KAD 300 @ 285 HP is a good example of this era...). Less weight, mass produced components, engineering "improvements", led to machinery more on the edge of performance envelope and with less tolerances of error/failure... Later we've had emission control etc., which have led to the evolution of electronic controls, sensors galore etc. The combination of "Start and go", edge of performance envelope, irregular use, lower tolerances and electronics does not combine very well with the salty environment where we tend to keep our pride and joy.

Give me an engine that is run for prolonged periods at operating temperature, maintained frequently and serviced well and I'll be more happy with that at thousands of hours, than something that have been stopped/started infrequently and used for short hops only at a couple hundred of hours....
 
I had 80,000+ hours out of a Cummins K19 on my commercial boat (replaced like for like at the time as there was a good deal on offer) yet the 400 hour Volvo KAD300 on my toy boat somehow makes me more nervous.
 
But you don't hear of KAD300's having many more problems than say KAD42's.
(lets ignore what happens if the tappets go way out of adjustment).
Engineering improvements have generally gone hand in hand with the power increases.
Improved cooling, fuel metering, different cylinder heads, turbos, air systems, manifolds ... problems arise when manufacturers just crank up the fuel pump settings without upgrading the other components.

But realistically, most small high powered marine leisure diesels will be lucky to reach 2500-3000hrs without a rebuild or replacement. At an average usage of 50hrs a year, that's a lifespan of only 50-60 years.

Errm ... can someone remind me again why I need to be worried about that?

.
 
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It's not really fair to compare a boat in everyday commercial use with a leisure boat. the regular use , plus servicing , keeps an engine and other mechanical and electrical going strong.
It seems to me leisure boat engines are more likely to develop problems due to absence of use and neglect of service rather than high hours.

It also seems to me 400 hours on a kad engine, or any other diesel, should be not yet fully run in.
 
Portofino said:
A displacement boat ,s engine has an easier life than a planing boat.
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Yes and no, L.
That is somewhat true with D pleasure boats, because most if not all of them have oversized engines, often twin, and they don't need to deal with anything else than ...ermm... pleasure cruising.

Fishing boats are a completely different kettle of fish - if you 'scuse the pun.
To start with, they are strictly single screw (well, aside from those which should be more aptly called fishing ships), and their main engine is just as powerful as the boat needs - albeit rated for continuous duty, of course.
You know, fishermen aren't keen on spending more money for a bigger than necessary engine, just for the sake of having some reserve power...
Besides, the engine is often run at or very close to WOT, particularly when heading back home with the boat filled to the brim with the catch.

Mind, I fully agree that the engine hours Sandyman mentioned are unheard of in pleasure boats, but it takes much more than the P vs. D hull to explain that...
 
Summer. Wine said:
Gardners are revered here in N.Z. by displacement launch owners for their reliability and longevity, not to mention that lovely sound.
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...and smell...recognise one a mile off. The only engine the SFIA would accept as a rebuild for a new boat. Renowned for economy as well, in the 70s when fuel was 1p a litre we used to laugh....

The Ford dover can be blown up to 320hp, but Sabre or Mermaid used to fit stuff like different conrods and oil cooled pistons (??). One chap has a jet drive off a Sabre, he got special dispensation to run it up to 3000rpm. Not heard of any special trouble.
When I asked the engineer should I (12000hours) have the injectors looked at he said does it start, does it run clean. I asked about modern fuels being a problem, he held up a pen: "if your nozzles are this size, a modern car has nozzles like a needle" The high pressures needed erode the nozzle tips, plus the fuel is hygroscopic so attracts water. Friend with a 2012 engine has had two lots of injectors already. Also, with electronics, the local lifeboat fell off a wave and (Caterpillars) went into limp mode. I suggested to my local engineer he could get hold of older engines and rebuild them to sell, get away from the electronics problem.
 
FlowerPower said:
But you don't hear of KAD300's having many more problems than say KAD42's.
(lets ignore what happens if the tappets go way out of adjustment).
Engineering improvements have generally gone hand in hand with the power increases.
Improved cooling, fuel metering, different cylinder heads, turbos, air systems, manifolds ... problems arise when manufacturers just crank up the fuel pump settings without upgrading the other components.

But realistically, most small high powered marine leisure diesels will be lucky to reach 2500-3000hrs without a rebuild or replacement. At an average usage of 50hrs a year, that's a lifespan of only 50-60 years.

Errm ... can someone remind me again why I need to be worried about that?

.
Click to expand...

That cheered me up... then I realised my Perkins Sabre coming up to 1900 hrs... although its not small or high powered..
 
Firefly625 said:
That cheered me up... then I realised my Perkins Sabre coming up to 1900 hrs... although its not small or high powered..
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I know a marine engineer that stripped a pair of M225Ti down for a rebuild as they had done 12000 hours in a commercial boat, they we're like new inside.

You'll never wear yours out.
 
fisherman said:
The Ford dover can be blown up to 320hp, but Sabre or Mermaid used to fit stuff like different conrods and oil cooled pistons
Click to expand...

Steel main bearing caps too. And that awful two stage fresh/salt water charge cooler than I think is not available now.

Sabre did a version for which they cast a special block that's 6.7 litres that went to 370hp, bit of a short life I'm told!

Cummins 5.9bt went to 480, then the 6.7 version went to 550 and I think now a 650 rating?
 
Same engine more power = less life, Sabre wrung the the the Ford's neck till it died. from 120 to 212, and that was it. They upped one a bit to 350 but that proved to be too much. Give me my old fashioned tractor Ford 180, they live forever, and when they stop they are soon fixed. I also have shied away from outdrives as well LOL
 
omega2 said:
Same engine more power = less life, Sabre wrung the the the Ford's neck till it died. from 120 to 212, and that was it. They upped one a bit to 350 but that proved to be too much. Give me my old fashioned tractor Ford 180, they live forever, and when they stop they are soon fixed. I also have shied away from outdrives as well LOL
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A good measure of how worn out and engine is, is total fuel burn through its life, its an expression of both hours and load. I know the CAT ACERT engines keep a record in the ECU. Nice.

I worked on some big Cats, 3516 and 3520, used in power gen, burning waste coal mine gas, over 120, 000 hours and stillgoing.
 
Thames Police sold a Botnia Targa with Volvo AD41's on outdrives a few years back with 25000hours !
Think it's all down to usage and servicing.
 
Sandyman said:
What a fool. It was just about run-in :) Seriously 42k Hrs is nothing if shes looked after.
My Ford 2712e is 40 yrs old so what? runs sweet as a bell & no electrics to go wrong.
Click to expand...

+1 - why change something that isn't broke - it's all in the care of the engine
 
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