Modern common rail engines or traditional full mechanic motors.

[Chanquete]

There are people concerned with the water sensivity of electric circuits in marine engines,
Considering that traditional all mechanic engines are more reliable and trustworthy in a marine environment.
For example they prefer the old volvo 2030 compared with actual D serie Volvos.
Are they right?

 

[PaulRainbow]

There are people concerned with the water sensivity of electric circuits in marine engines,
Considering that traditional all mechanic engines are more reliable and trustworthy in a marine environment.
For example they prefer the old volvo 2030 compared with actual D serie Volvos.
Are they right?

The D series equivalent to the 2030 is a normally aspirated mechanical injection system (D1-30). Bad example ?

 

[prv]

I've worked around boats that have Yanmar JH series engines in a couple of different sizes; these are the smallest common rail units I'm aware of in marine use (starting at 40hp).

Not had any problems with them so far. The ECU casing appears reasonably well sealed against splashing water, though I doubt it's good for submersion. If I had one on my own boat I'd be more concerned about tighter fuel tolerances (which I assume common-rail systems have?) than the electrics.

Pete

 

[Chanquete]

The D series equivalent to the 2030 is a normally aspirated mechanical injection system (D1-30). Bad example ?

You are right Rainbow. I elected a bad example. Sorry
D3 and D4 which more potent than the 2030 are common rail engines.

 

[pcatterall]

Our old Perkins is simple and reliable. I think it will tolerate poor fuel and damp conditions better than some modern engines.
Fuel consumption bearing in mind we run at fairly constant engine speeds compares reasonably with modern equivelants.

 

[PaulRainbow]

I don't see any reason for the electronics to be an issue, we already have plenty of delicate electronics onboard, such as radomes stuck up masts and navigation electronics outside at the helm. The real issue, as Pete said in post #3, is fuel. Common rail systems employ extremely high fuel pressures (more than enough to force fuel through human skin, resulting in serious problems, such as amputation), at these pressures tiny particles of dirt or water can cause serious component damage.

I have a customer whose boat is fitted with a pair of V8 common rail engines, each engine has 5 filters !

 

[RichardS]

I also agree that fuel quality is likely to be the bigger issues as common rail fuel injection engines are now an extremely well developed technology.

I also agree that I instinctively prefer a more "mechanical" engine, even if it means sacrificing a bit of fuel economy, especially in the marine environment, simply because mechanics are more tinkerable than electronics. However, especially in more powerful engines, that's rather like King Canute preferring to stay dry.

Richard

 

[prv]

I also agree that I instinctively prefer a more "mechanical" engine, even if it means sacrificing a bit of fuel economy, especially in the marine environment, simply because mechanics are more tinkerable than electronics.

Can you really do much tinkering inside of an injector pump in a yacht's engine bay, though?

Pete

 

[ibbo]

You can put new injectors on without needing a laptop though.

Mike

 

[rotrax]

I don't see any reason for the electronics to be an issue, we already have plenty of delicate electronics onboard, such as radomes stuck up masts and navigation electronics outside at the helm. The real issue, as Pete said in post #3, is fuel. Common rail systems employ extremely high fuel pressures (more than enough to force fuel through human skin, resulting in serious problems, such as amputation), at these pressures tiny particles of dirt or water can cause serious component damage.

I have a customer whose boat is fitted with a pair of V8 common rail engines, each engine has 5 filters !

Surely ALL diesel injection systems use extremly high pressure.

I recall our instructor at Technical College, back in the early 60's, firing a jet of diesel through a bit of 6 ply plywood, just using an injector test kit.

You certainly would not want that hitting a finger...............................

 

[prv]

You can put new injectors on without needing a laptop though.

Is a laptop needed to change injectors on yacht-sized marine engines? It isn't on my common-rail-engined car.

Anyway, I have a laptop

Pete

 

[Roberto]

I met a UK flagged boat in Brazil with a modern engine, the crew was getting mad with fuel: when the engine sensed Brazilian fuel being used, it would shut down (electronically) a few minutes later, probably because of emissions. Happily, the two guys had some spare jerricans with European diesel: they used it to start the engine, then reverted to local diesel to have the engine running for as long as possible, it eventually stopped so they started it again with european diesel, and so on.
Total nightmare.

 

[RichardS]

Can you really do much tinkering inside of an injector pump in a yacht's engine bay, though?

Pete

Not much possibly with that specific part .... but, taken in-the-round, mechanical devices can be tinkered with and electronic devices can't.

Richard

 

[john_q]

Entering a difficult harbour with strong wind over tide and the engine decides to go in "limp home mode" sounds pretty frightening to me!

 

[Bobc]

The biggest problem is that the nozzles on common-rail engines are so fine, and the pressures so high, that the tiniest bit of crud can cause major problems. Still to be convinced about relying on an ECU also. I prefer mechanical engines that you can put any old fuel in and that I can fix.

 

[PaulRainbow]

Surely ALL diesel injection systems use extremly high pressure.

I recall our instructor at Technical College, back in the early 60's, firing a jet of diesel through a bit of 6 ply plywood, just using an injector test kit.

You certainly would not want that hitting a finger...............................

Common rail engines have significantly greater fuel pressure than older engines, up to 36,000 psi. That's over 10 times the typical mechanical injector pressure.

Contaminants in a common rail system (particles less than 2 microns) will score and/or damage the high pressure pumps and the injectors. At those pressures, a faulty injector can seize a piston, blow a hole through the top of a piston and cause catastrophic engine failure.

 

[PaulRainbow]

The biggest problem is that the nozzles on common-rail engines are so fine, and the pressures so high, that the tiniest bit of crud can cause major problems. Still to be convinced about relying on an ECU also. I prefer mechanical engines that you can put any old fuel in and that I can fix.

Beat me to it Bob :encouragement:

 

[oldharry]

I think it is the fixability when the lump goes clunk and silence. Electronically controlled engines are all very well, but every electrical connection becomes a potentially weak point, giving a great deal more to check, and as we all know even the professionals can struggle with diagnostics.

Keep it simple seems to be the seamanlike option. If onboard electronics pack up its not the end of the world (you do carry compass and charts dont you? ) A dead engine can be seriously hazardous.

 

[Greenheart]

Interesting thread. Is anybody still building diesels which aren't reliant upon electronics and very pure fuel?

 

[Tranona]

Interesting thread. Is anybody still building diesels which aren't reliant upon electronics and very pure fuel?

The small diesels most of us use are still mechanical, although some (like my Volvo) use electronics for the control panel. However most have been dependent on electrics for the last 40 years or so to start them. You need to go back to the 70s to find popular engines (such as Yanmar YB and YS types) for engines available without any electrics - that is with hand start only and dynamo an option!