Why So Many Boats with Rebuilt / New Engines ?

[goboatingnow]

Originally Posted by Chief Engineer

My question is what car engines are used?

There really isn't such a thing as a "Corvette" engine.....It is a General Motors Block

Unless you were posting in jest

Nissan engines, mitsubishi , Volvo/Renault , fiat, ford , then there's all the truck engines ( Scania? Deutz, mercedes, volvo, perkibs et ) and of course kubota.

Dave

[CaptPatAg]

The engines don't wear out, they rot away, and all the little pieces go bad. The salt water is hard on everything. Just take a look at the rust on your "stainless".

[Arch Stanton]

I think part of the reason there are so many re-powered boats on the market is that people are generally more likely to replace a boat motor earlier than they would a car motor.

You don't totally know a motor's end of life until you find it. Cars you can push up till the moment the engine gives up the ghost, without a whole lot of risk, because the consequences are relatively low.

A failed motor on a boat, on the other hand, could mean losing the vessel or lives.

It probably doesn't take many boat engine scares before you stop trusting it and wish you had a new one.

[Exile]

I had the same question when I bought my first diesel auxiliary powered sailboat a few years ago. After less than a 1000 hrs. on my 1999 Westerbeke 82B, it was declared a total loss after two of the cylinders had seized from long-term saltwater back-siphoning. The ins. co.'s surveyor concluded that it had occurred over a number of years from improperly sized ID exhaust hose. It was deemed a "design defect" and I luckily had coverage. When I studied my service manuals, I discovered a service bulletin from years ago where Westerbeke had said to replace any 2" ID exhaust hose with 3". Nobody caught it, even though a dealer had repowered the boat with a larger engine in 1999.

Why not install a simple ball valve to close off any back siphoning below the elbow or other suitable place?? If the owner forgot to open it, the engine would just stop -- no harm. To the OP, why does my '05 Cummins-powered Dodge truck have 130,000 miles with no issues? Never any water in the fuel, no injector or pump rebuilds, no cooling issues, 5,000 oil/filter changes, 20+ mpg. I understand that the corrosive saltwater environment is tough on many things, but perhaps like the OP, I don't quite understand why so many marine diesels seem to go south before their time, especially when the failure is caused by components that should be isolated from the otherwise difficult operating environment.

FWIW, I believe my 82B is a marinized diesel mfg. by Mitsubishi, and my diesel genset (also Westerbeke) is a Mazda (or the other way around).

[Piney]

Originally Posted by Chief Engineer

The little known factoid is that having a new engine or rebuilt engine does not usually add to the value of a vessel.

Exactly!!

[sdowney717]

Diesel is the perfect liquid fuel, generally wont explode, but will burn.
There are other ways to make power with diesel.
Cyclone engine runs on any liquid fuels
Cyclone Power Technologies - How It Works

Perhaps some day we will get more reliable engines.

why its better, any thoughts?
http://www.cyclonepower.com/better.html
Regular piston engine is like a giant burning heater which creates tremendous amount of wasted heat energy. Much of that heat goes right out the exhaust without doing any useful work.

a better more reliable engine is good for the user but bad for engine builders.

A 350/lb Cyclone Engine of 38-cu/inch displacement develops over 850ft/lbs of starting torque (which is more than necessary to eliminate the transmission). Transpose the decimal to 380 cu/inches and you will appreciate the implications of this technology when a manufacturer scales the Cyclone to a size suitable for heavy road transport. The starting torque of the Cyclone Engine is higher than an electric motor of comparable size, but similar in respect that neither requires a transmission, just a simple forward neutral and reverse lever is required

[SailFastTri]

I'm no mechanic but another way engines are used differently in boats is they are always under load while underway. A car/truck accelerates/decelerates for traffic signals and goes up/down hills.

I might be delusional but it makes sense that when an engine is decelerating the cylinder vacuum sucks oil into the micro spaces of the cylinder wall/rings, while underway the compression blows it out. A boat engine is like a car/truck engine that's always accelerating or going uphill when it's not idling.

[mbianka]

Originally Posted by CaptPatAg

The engines don't wear out, they rot away, and all the little pieces go bad. The salt water is hard on everything. Just take a look at the rust on your "stainless".

Agree with that! My once reliable Westerbeke 27 went south rather quickly once the head gasket leaked fluid onto one of the cylinders and cracked it. Replaced it with an electric propulsion system that has been much more reliable and maintenance free. Diesels do seem to work great until one day they don't. When I look back I've had a number of those "little things" that happens to diesels that have interrupted some of my cruises. Antifreeze leaks, exhaust elbow corrosion, clogged water intake etc... all those issues went away with electric propulsion. When I look back to the diesel days it's a much more reliable auxilary propulsion system than my diesel was.

[headhertz]

Originally Posted by mbianka

Agree with that! My once reliable Westerbeke 27 went south rather quickly once the head gasket leaked fluid onto one of the cylinders and cracked it. Replaced it with an electric propulsion system that has been much more reliable and maintenance free. Diesels do seem to work great until one day they don't. When I look back I've had a number of those "little things" that happens to diesels that have interrupted some of my cruises. Antifreeze leaks, exhaust elbow corrosion, clogged water intake etc... all those issues went away with electric propulsion. When I look back to the diesel days it's a much more reliable auxilary propulsion system than my diesel was.

A properly sized battery/motor setup does seem like a somewhat elegant solution for those who have shore power and need the motor only for docking etc. What kind of run-time do you get out of yours? How many KWH does your battery bank store? What kind of batteries do you use?

One thing that might concern me about a motor is internal corrosion caused by salt air and mist? Do you operate in a saltwater environment? Is the motor marine rated or repurposed from another application?

[Exile]

I'm waiting for the type of diesel generator/electric propulsion motor that has been used in big cruise & other commercial shipping for a long time to come to recreational vessels at a reasonable price. I think it's here but too $$$ at this time. The diesel runs at a constant low idle thereby saving fuel & simplifying maintenance. The electric propulsion motor is compact & also more efficient. The set-up also supplies a/c current to run appliances for charging batts. One diesel motor vs. two! Lots more room in the engine compartment!

[mbianka]

Originally Posted by headhertz

A properly sized battery/motor setup does seem like a somewhat elegant solution for those who have shore power and need the motor only for docking etc. What kind of run-time do you get out of yours? How many KWH does your battery bank store? What kind of batteries do you use?

One thing that might concern me about a motor is internal corrosion caused by salt air and mist? Do you operate in a saltwater environment? Is the motor marine rated or repurposed from another application?

I agree those going out for daysails and come back to a dock with shore power it really is a no brainer to go with electric propulsion as a diesel replacement. I however mostly cruise and my boat mostly resides on a mooring or at anchor most of the time and it still works for me. I've got a 10 kw (4 8A4D's in series) battery bank available but, I use the amps from it sparingly and augment it with a Honda 2000 eu generator that can charge the bank or move the boat at about 3 knots alone in clam conditions for as long as I have fuel. BTW the generator runs 5 1/2 hours on a full tank that is a little larger than a gallon. I've done this for up to 10 hours so far. Though it is primarily a "sailboat" , I do "electro sail" and run the prop slightly to negate prop drag giving me a little bump in speed when I sail. The minimal amp draw doing this is easily made up by my solar panels and 48 volt wind generator or easily replenished by the Honda generator if needed.
Yes, I do operate in a saltwater enviornment and I agree the motor will have to be inspected for any corrosion issues. But, there is much better access to it than many areas of my diesel engine. The motor has been used by ASMO MARINE for a number of years is also used by the British military in their vehicles and is also use by BETA MARINE for their hybrid engine system:
THE BIANKA LOG BLOG: REPORT FROM THE ANNAPOLIS BOAT SHOW:PART 4: ELECTRIFYING
So I feel confident it is robust enough for my boat needs. At forty pounds it is also easy enough to replace and one could also easily carry a spare if one wanted. I personally don't see the need to do so. It is recommended that the brushes be changed after 3000 hours. But, I certainly won't wait that long. My 1986 diesel died after only 1800 operational hours. I expect the electric motor to do much better from what I have seen in my four years since I converted from diesel.

[rtbates]

because too many folks treat them like semi-truck diesels?

[Dockhead]

Originally Posted by headhertz

I suspect that most boats engines never get the use that a car gets in 100k miles (2000 hours seems like a conservative estimate for a mostly highway-miles equivalent).

I can read engine hours on my primary land vehicle (it is a Range Rover with a BMW onboard computer). I don't think you will ever find anyone averaging 50mph during every engine hour over the life of any car. I drive part city, part highway (admittedly a very big city with big trafffic jams). I have about 6000 hours on my engine for about 100,000km covered (about 62,000 land miles), for a lifetime average of about 16km/h or 10mph.

The engine, a 4.4 liter BMW V8, is in perfect condition and doesn't burn a drop of oil between changes. 100,000 miles will be about 10,000 hours, and I have no doubt it will still be running well.

So I guess I'm supporting your point, only even more extremely.

Yes, I wish our boat diesels would do as well. I agree with those who believe that disuse is the main problem.