Common rail marine diesel engine v standard

[sailorboy1]

Originally Posted by Sulaire

If you were going to re power your boat would you go with common rail or standard engine.

Assuming equal lead time and availability. I would do the one with the lowest total purchase/installation cost.

[Cadence]

Originally Posted by moseriw

Nope - Do not buy common rail or turbo just a good old tractor engine. It will last long 1600 - 1800 rpm
and if you are lucky you will not have any problems with scrap fuel

[did-g]

Originally Posted by a64pilot

In five or ten years, it’s likely most of us won’t have a choice.
Try buying a carbureted automobile, with points ignition, and drum brakes for instance.

In ten, fifteen years you'd be lucky if you can find a new small diesel engine at all...

[geoleo]

I prefer the older yanmars and volvos that could be hand/foot cranked if the batts went down!!! Had one for 30 years and cranked it once

[charliehows]

truth is - most of us learn to live with whatever engine the boat has when we got it, no-one goes out and spends $20-$50k on a new engine because they think a common rail diesel would be better in some unspecific way, than a mech. injector pump engine. Personally, i love old diesel engines; once you get familiar with them and tidy up all the excremental things dimwitted amateurs have done to them over the years, they're like an old pair of tramping boots, comfy and indestructable.

[a64pilot]

Once you live with a common rail for awhile, you may change your mind.
I had my Duramax Diesel for 15 yrs I guess it was, smooth, quiet, and very powerful.
It was odd to hear it start cold, it might knock once, then it would be as quiet as a gas motor, really odd to hear. It accomplished this by having a pre shot of fuel at lower RPM, it would shoot a little bit of fuel, that would ignite and then main fuel injection event would happen without any rattling or knocking.
There just wasn’t enough time to do that at higher RPM, and you could hear the pre injection turn off when it did. Up above 2600 I think. Max was maybe 3500?
GM called it pilot injection, Ford split shot.
There were self protect modes in the engine overheated etc, it would turn off a few cylinders and move those around to keep from overheating, and it made POWER, real power.
The early ones did suffer from fuel injector problems though as common rails run stupidly high fuel pressures, up around 30,000 PSI I believe.

[Oceanride007]

Was a Marine Engineer for many years, few thoughts that I have gathered on my way.



For

1. Electronics on side of engine have been pretty reliable.
2. You may not have a choice in years to come, Euro and california type rules are making Nitros oxide emission may make small engine Common rail mandatory.
3. Common rail will get more economical and reliable.


Against
1.You need lots of electric power to drive the injectors, lose alternator you'll rely on Solar with short duration, more reliable with Generator.
2. Those injectors still rely on good oil lubrication that is less tolerant of gum deposits, first thoughts are you may need to use synthetic and change more often.
3 Fuel quality, need much finer filtration and dryer fuel for the higher pressures.
4. This is the biggy for me. To reduce Nitros oxide emissions you need to retard injection timing. To my thinking that means less efficiency, perhaps higher exhaust temperature if they don't use a longer stroke. Its a mistake to assume better emissions and more efficient, any efficiency gain is at cost of higher injection pressure, makes engine less reliable.


I won't be the first, as I need to know it will be good for at least 10 years.

[a64pilot]

Your number 2, if I understand what your saying that is only the Ford HEUI style injectors which is not a true common rail, they used engine oil pressure to magnify fuel pressure to the high pressure needed for injection, essentially each injector was its own HP pump.
I’m not sure if that systems exists anymore.

Different systems explained, there is more than one way to skin a cat, and if you read, you’ll find out just how sophisticated these systems are, with apparently ford using up to 5 injection events per power stroke.

http://www.trucktrend.com/how-to/exp...asic-training/

However I think it very safe to say that any of these sophisticated injectors are extremely intolerant of any dirt in the fuel as a tiny particle at 30,000 PSI could cut an injector nozzle like a water jet I’d suppose

[unbusted67]

I've had a common rail catastrophe. Third day back as a captain on a commercial passenger vessel and the fuse protecting the buss bar that the cpu was plugged into corroded and popped. This was all during a heavy Westerly and if it wasn't for a good anchor I would have bit it along with my passengers. Scary stuff.

I don't really blame the technology as much as I blame the captain who had been running the boat before me and not maintaining hatch or window gaskets and allowed for the leak that caused the corrosion to begin with. Common rail, traditional engine, properly maintained they will run for a very, very long time. If you let them fall apart....then you might die.

[billknny]

Originally Posted by Cadence

Probably someone with a mechanical fuel pump can afford to have one aboard, and a gasket, if they are doing extended cruising..

LOL!! That's rich.

Have you priced a replacement injection pump for your engine??? I do not personally know of ANYBODY who carries a spare injection pump. Not a lift pump... an injection pump...

[billknny]

Originally Posted by moseriw

Nope - Do not buy common rail or turbo just a good old tractor engine. It will last long 1600 - 1800 rpm
and if you are lucky you will not have any problems with scrap fuel

I have a Volvo TMD22 turbo. It is getting a bit long in the tooth (8000+ hours), and there are many things I do not like about it.

To replace it with a non-turbo engine would add over 600 pounds to the boat! As much as I dislike the extra maintenance a turbo adds, 600 pounds is a HUGE weight penalty to carry around that will slow me down every day I am sailing. I'll deal with the turbo complications.

IfI had a big heavy trawler that I motored--slowly--everywhere, my answer might be different.

[billknny]

Originally Posted by Stu Jackson

My understanding of the differences, in addition to those already mentioned, is that CR engines require electricity to continue to run once started. A standard engine, once started, needs only air and fuel.


That difference, if I'm correct, is huge in a recreational boat, not so at all in an automobile or truck.


Sure, a stable and consistent electrical system is certainly preferred on your boat, but I'd rather be on the last legs of an electrical system failure and be able to start my engine and keep it running without any power than the other option.


Sure, an argument could be made that once the engine starts the alternator will provide the power, but an alternator failure could well have been the cause of the electrical system failure.


It's risk analysis 101.

I guess it matters if you consider your boat a sailboat that has an engine, or a motorboat that happens to have sails.

[billknny]

Originally Posted by john61ct

...the EMP-proof crowd is growing.

They are easy to find, they have the tinfoil hats.

[Barney21]

Originally Posted by Lepke

If you're crossing oceans or have other reasons for reliability, I would pick an engine that was 100% mechanical with no electrical needs other than starting.

I had tugs and other commercial boats. I still have many working friends. Electronics in a salt water environment are not as reliable as the old mechanical systems. They're not even reliable in trucks, but there you can pull over and wait for a mechanic. I know people that carry a full set of sensors, injectors and circuit boards as spares. Hundreds, if not thousands of dollars tied up in spare electronic parts. A fisherman friend with a new electronic diesel could only idle back in from 100 miles out. And a hundred other stories.

Another issue is the time getting parts at far away places.
The people that love them are the ones that fix them, have the specialized diagnostic equipment, and sell parts.
My diesel pickup is just as bad. My glove box if full of spare electronic parts.

All of the above makes lots of sense to me. I would suggest with one addition ,if you go the CRD route I would run 2 (at least)CAV type filters on the fuel feed line and one CAV type on the return line to the tank. I know the "old Style " diesel systems were designed to run of fuel available at the time. But I am not so sure if the quality of diesel would be that good in some countries especially on a Marina. CRD systems will not put up with poor quality fuel. But remember to change all the filters very regularly if CRD is your choice.

[Sulaire]

Thank you to everyone for the comments.

My take away is that i would prefer CR due to quiet/smooth.

But i have suffered many times from bad fuel in far flung places, to the extent that I fitted a fuel polishing system in the boat. Even with that; in my experience, marine diesel in some places is not up to garage forecourt standards!

The thought of not being able to fix a dirty fuel problem, where the engine shut down is not where I want to be!

I am pretty sure I would stick with standard diesel at the moment, but I am going to ask the dealers about the problem of dirty fuel in CR in case i am wrong.

In the end i wonder if the fuel marinas are dishing out is upto the standard required by these new engines, they might need to up their game.