# Rebuild vs replace diesel engine



## Ilenart

Latest copy of (Australian) Cruising Helmsmen has an article replacing or rebuilding a diesel engine ("Fix it or flick it"). Not a bad article, however one section I don't agree with is this statement.

_The first question to ask is: how old is the old engine? If it's heading towards the 20 year mark then even talking about a rebuild is probably not a good idea._

The article gives a couple of other reasons for not rebuilding (ie damage to the crank shaft, pistons rings, etc) however the main issue stated is age with 20 years being the magic number. I would of thought a number of other issues would come into the decision including:



engine hours

how well the engine has been maintained

how easy it is to obtain spare parts

engine access, ie can the engine be lifted out easily or do you have to dismantle half the boat to get at the engine

etc, etc

The two most important ones would be engine hours and availability of spare parts.

For example, my boat has a 98HP six cylinder Nissan SD33 diesel engine installed in 1979 (29 years old). Engine is keel cooled (ie cooling water circulates though pipes mounted on the outside of the hull - no saltwater through the engine). Engine has around 2,700 hours, of which I have done about 150 hours over the last 2 years. When I brought it two years ago had it inspected by a diesel mechanic, who gave it a clean bill of health. Have had no problems with the engine during this time. Spare parts for this engine are readily available (it's the same engine that was in the Nissan Patrol from around 1981 to 1989).

Over the next 2-3 years one plan is to remove the engine as part of a major boat rebuild and have it either overhauled or replaced, depending on how the engine has gone, what the inspection shows, etc. However according to the article replacement would be the only option.

Any advice / opinions / comments?

Ian (ilenart)


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## theartfuldodger

Wondering maybe if such things of world wild availability of parts, the emission issues, fuel economy, weight and size might be in there as well. I understand the old statement if it's not broken why fix it. The replacement might also lead to new spins offs as wiring updates, easier controls to just mention a few.


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## Maine Sail

*I think..*

Not having read the article my guess would be they say 20 years because at that point the following items are pushing their odds on a boat..

1) Alternator
2) Motor Mounts
3) HX if equipped
3) Starter
4) Tranny
5) Injection pump
6) Water pump
7) Fuel lift pump

Basically, around here, a diesel engine rebuild includes the internals of the engine, machining of any internal parts and the gaskets required to put it back together. These quotes usually only include new rings and gaskets. If you happen to need a new cyl head or pistons the price is on top of the quote because they don't know until they get in there. These re-builds usually DO NOT included the injection pump unless you specifically ask or any other part of the motor for that matter.

My neighbor recently, well three years ago, re-built his Yanmar 3GM and the total re-build cost was over 5k. All he got was R&R of the motor, new rings and gaskets and internal machining and a little spray paint. Suffice it to say most re-builds do not re-build the starter, alternator, water pump, acid dip the HX or even look at most if not all external components..

For 5k every other component on his motor was still pushing 20+ years or original. At that time he was quoted 7k for a brand new motor with transmission and all associated parts. Since that happened, he has continually belly ached about how he should have purchased a new motor because his tranny, alternator, motor mounts and a few other items have since let go too. He's spent well over the price differential between new and re-built in the tree years since he had the Yanmar overhauled.

There was a time when a re-build was worth the differential but with labor rates pushing $100.00 US per hour, and parts cost as high as they are, that differential is very easily eroded and not always worth it when you consider the age, and cost, of the external components when purchased individually..


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## hellosailor

Ian, I don't see any mention but one big question is whether the engine was salt-water raw water cooled. Raw salt water can eat out cooling passages in the engine, making it incredibly expensive or totally impossible to rebuild. After enough years--it just doesn't pay to gamble if that's part of the question.


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## chucklesR

I think I can understand why they would say that. Technology over the past 20 years has greatly changed. If the break point on cost is within budget I'd go with a new engine and gain the rather considerable savings in weight and fuel economy and count the controls and monitoring capabilities as gravy.

You might be able to find plenty of spare parts for that old Ford (for example) but can you change the impeller in 5 minutes like I can on my new Westerbeke that I've fitted with a swap in thumbscrew quick change unit?
Can you plug it into a NMEA 2000 network and monitor it on a laptop for compression, fuel flow, power, temp etc - that really lets you know what's going on inside it - or do you troubleshoot problems by ear and smell?


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## kengoodings

Our Volvo-Penta MD11C two cylinder Saildrive had no compression or power.
30 year-old Volvo parts are hard to come by and we waited nearly 9 months for components to replace the cylinder liners and rings. After all this time we bit the bullet and purchased a modern 4 cylinder saildrive for $13k A hard decision but full time ocean cruising demands a reliable auxillary in the boat.
We'll have that soon, launch day is fast approaching and our Niagara 35Mk1 will have wings with that 39 hp !!!


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## billyruffn

With the cost of a rebuild a very substantial fraction of the cost of a new engine (installed), and assuming you're looking to keep the boat for the foreseeable future, you might consider how you evaluate the two options from the perspective of ten years from now:

Option 1: Spend X for a new engine and ten years from now you have a ten year old engine with about 1000 hours in service (well maintained, that's almost as good as a new engine).

Option 2: Spend 70-80% of X to rebuild the current engine (assuming you have it done professionally, that's probably a reasonable estimate of what you'd spend) and you then have a 39 year old engine with 1000 hours since a rebuild and 3700 hours of total service.

Shift perspective slightly....assume you're trying to sell the boat ten years from now. How would a prospective buyer look at the relative value of these two options?

Finally, there's always the 'do nothing' option -- if it's working fine, keep loving it and replace it down the road when the engine's performance warrants. At 75-100 hours a year you could probably live with what you've got it for a long time. On the other hand, if you're doing the refit in preparation for a long, multi-year voyage to the far corners of the earth, then focusing only on the rebuild vs replace options probably makes sense.


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## danjarch

Another issue from professional mantaince stand point is that the rebuild/ replacement is suposed to last another twenty years. Parts that are avalible now may not be in ten years. Having worked on a 125' shcooner that used older technology so that it would match it's sister ship, I can say that you'd be better off replacing it. extra parts may look avalible, but when they show up will have to be modified or will have a shorter life then intended. 

An example would be that we had to replace most of the silenoids on the main engine and one of the generators just about every other year. This was because our's where originally 32 volt and the replacements we could get were 24 volt. They worked but would fry out petty quick. All are electrical componants had to be sent out for rebuild. It was rare to find a new or already remanufactored sitting on a shelf. Any time something broke we'd have to either jury rig a temporary sulution or put the boat out of service untill we had the parts rebuilt or refabricated. Even simple items like the pump braket or the transmission linkage, would have to be fabricated or retro fit.

Thats what you get into. It may be that you can still get impellers but there half again as much, only made by one company, and made using cheap rubber. Not like you can go somewhere else to get them. Same goes for gaskets, random brakets, control linkages, electronics, and just about all the stuff that should be no biggy, but becomes a major hassel.

The other thing to consider is doing all the other refitting you have planned including deciding what new motor you'll use when you repower, then leaving the existing engine in place till something big goes.


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## Ilenart

Thanks guys for all the input. Much appreciated.

Hellosailor, engine is freshwater cooled via keel pipes. No saltwater through the engine. Saltwater does cool the gearbox via a heat exchange then out through the exhaust, however this system is separate from the engine.

Billyruffin, your "do nothing" option is basically what I am planning on doing for the next two to three years. The replace /rebuild is one option that may come up after that.

Know one has commented on the number of engine hours. My understanding is that engine hours as opposed to years is a better estimate of engine life, which is the main issue I had with the article. I have often read that you would expect 5,000 to 8,000 hours from a diesel engine before you would expect a major overhaul. What I am thinking (hoping?) is that a detailed examination of the engine shows no major problems / issues. In that scenario I believe reinstalling the engine would make sense, as the engine would still have 40-60% life left. 

However, if the detailed examination showed major problems then yes a new engine would make sense.

PS, just reading some of the posts in "Theory of fibreglass blisters" phew!


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## danjarch

The reason you can't use engine hours after say year fifteen is that time also takes it's toll. The same in cars. Gaskets deteriate, metal corrodes, and even the insulation on the internal wireing goes bad with time. Your parts including both the rubber and metal ones have now been soaking in a slightly toxic envionment for a long time. Plus the short uses it's most likely to have expeirenced is harder on an engine then long hours are.

It's the same in cars. A 1973 ford truck with only 45,000 miles will have as many or more problems then a 2003 ford truck with 145,000 miles. In the end if you think your engine, transmission, and the other parts that are attched to it are in really good shape then rebuild it. But there is an old adage that goes " You can put a rebuilt transmission on an old engine, no problem, but a rebuilt engine on an old transmission will blow with in two years."

Same goes for rebuilding the top of an engine without rebuilding the bottom. Your basicly going to put a new power plant onto a worn transmission, as well as impellor pump and altenator. This engine's going to turn faster and give more tourqe then the old tranmission can handle. The bearing in the altenator are older and have fatigued both from they're use and from corrossion and the leaching out of carbon and iron that make up the steel. 

Thats why its not recomended. Plus for a couple of bucks more you get to advertise a new drivetrain when you go to sell it. A big advantage because most people are afraid of getting stuck with a blown tranny or engine. Add in the fact that the new stuff comes with a longer warrenty on more peices then the short warrenty that you'd get on a rebuild. And you can see why after twenty years no one really goes by the hours any more.


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## Ilenart

Ok, thanks Danjarch. Off to bed now, it's pretty late over here.


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## hellosailor

Engine hours certainly do count. The problem being, are they "hard hours" or "soft hours" ? With proper maintenance and load, or too many hours idling without load? Based on what logs or hour meters? And oil changes, etc?

If you can get a reliable grasp on engine hours and operating conditions, that very much matters. I'm just guessing that the authors felt after 20 years, parts can be problematic, corrosion can be problematic, and so on. But, a good engine, treated well, with parts still available, can last forever.


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## Valiente

kengoodings said:


> Our Volvo-Penta MD11C two cylinder Saildrive had no compression or power.
> 30 year-old Volvo parts are hard to come by and we waited nearly 9 months for components to replace the cylinder liners and rings. After all this time we bit the bullet and purchased a modern 4 cylinder saildrive for $13k A hard decision but full time ocean cruising demands a reliable auxillary in the boat.
> We'll have that soon, launch day is fast approaching and our Niagara 35Mk1 will have wings with that 39 hp !!!


Ken and I know each other quite well, and have broadly similar cruising plans, so I feel happy to agree that in his situation, replacement made more sense.

In my case, rebuilding makes more sense. As has been stated elsewhere, total hours and the cooling state make a big difference. So does availability of parts.

My engine is 20 years old, but has only 1,300 hours on it. A rebuild will very likely only reveal ring wear, and some other minor fixes. On the other hand, the pattern of 20 winterizations and low, cold hours could show a problem I don't want to face in Fiji three years from now. Also, my engine is not only fresh-water cooled (anti-corrosion anti-freeze, in fact), but the raw water is fresh water. So the pump, heat exchanger and starter will be replaced, but as they all work very well, they will be the spares for the trip.

My engine takes Mazda spares and gaskets as it's essentially a Mazda pickup block...there's about 100,000 of them still in Australia alone, working and being serviced. A full set of rebuild parts would run me about $7,000, with maybe $2,500 for the labour. A new engine would cost $15,000, plus extensive welding work, tank migration, shaft tube alteration, and so on added to that cost. Lastly, my engine is ridiculously easy to access: drop a hook directly down after lifting off the pilot house roof.

At 2,700 hours on a 29 year old engine, you are facing a situation closer to mine than to Ken's in that I assume it's working well, but it has been used sparingly. If that's the pattern, then the benefits of a new, lighter engine (that runs hotter and needs lots of air to get those fuel savings) might never match another 29 years of the same old engine, but rebuilt.

Just my thoughts...I've been mulling this over for about 18 months now, and my solution is mine alone.


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## MacGyverRI

hellosailor said:


> Engine hours certainly do count. The problem being, are they "hard hours" or "soft hours" ? With proper maintenance and load, or too many hours idling without load? Based on what logs or hour meters? And oil changes, etc?


1 engine hr. = 40 miles, that's the industry standard and most people can relate easier to xxx miles vs. xxx hours. (I was a heavy equip. mech. for 30 yrs.)

Hard or soft hrs.?? I never heard of that, but idling any diesel is not good for it and will kill it fast, always put some sort of load on it. The more load it has, the longer they will last. Don't baby a diesel, it's made to run under full load to last almost forever w/ proper care as long as it has the right oil. (Shell Rotella T 15W/40 is about the best all around oil you can buy)

If an engine is rebuilt properly then the starter/injection pump/injectors are also rebuilt at the same time and you basically have a new motor.

"Throw away engines" (just replace, rather than rebuild) don't have replaceable cyl. sleeves.


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## artbyjody

MacGyverRI said:


> Hard or soft hrs.?? I never heard of that, but idling any diesel is not good for it and will kill it fast, always put some sort of load on it. The more load it has, the longer they will last. Don't baby a diesel, it's made to run under full load to last almost forever w/ proper care as long as it has the right oil.


Maybe we should call Mythbusters in one this one... Diesels really do not care one way or the other as long as they are properly operated and cared for - and in some cases - some diesels like that on my F-350 run religiously regardless of lack of maintenance...

The biggest issue with any engine is over -revving, letting fuel varnish by sitting long periods of time, and in cases of seawater cooled engines - allowing seawater to sit due to not properly ejecting water and properly winterizing...


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## sailingdog

Jody-

You sound a bit confused in your post. First of all, AFAIK, Diesel fuel doesn't have the varnish problems when sitting for long periods of time, gasoline does.

Second, all engines do care about being run properly. If an internal combustion engine, diesel or gasoline, is run for long periods of time at relatively low loads and for short durations, bad things start to happen. You'll start to get carbon build-up or deposits in the engine. These deposits are normally burnt off when the engine is running under a heavy load. Running the engine for only short periods of time will lead to condensation in the block and rusting from the condensation. This is because the block never really warms up to operating temperatures properly, but is more a problem in gasoline engines than it is in hotter running diesels.



artbyjody said:


> Maybe we should call Mythbusters in one this one... Diesels really do not care one way or the other as long as they are properly operated and cared for - and in some cases - some diesels like that on my F-350 run religiously regardless of lack of maintenance...
> 
> The biggest issue with any engine is over -revving, letting fuel varnish by sitting long periods of time, and in cases of seawater cooled engines - allowing seawater to sit due to not properly ejecting water and properly winterizing...


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## artbyjody

sailingdog said:


> Jody-
> 
> You sound a bit confused in your post. First of all, AFAIK, Diesel fuel doesn't have the varnish problems when sitting for long periods of time, gasoline does.
> 
> Second, all engines do care about being run properly. If an internal combustion engine, diesel or gasoline, is run for long periods of time at relatively low loads and for short durations, bad things start to happen. You'll start to get carbon build-up or deposits in the engine. These deposits are normally burnt off when the engine is running under a heavy load. Running the engine for only short periods of time will lead to condensation in the block and rusting from the condensation. This is because the block never really warms up to operating temperatures properly, but is more a problem in gasoline engines than it is in hotter running diesels.


No I am not confused about my post. Owning a wide variety of powered contraptions... That rarely get used but always get up and go... However, I pay attention to the fuel... And FYI Diesel degrades.. while may not varnish will give varying declining return depending on volume and sit time... Which is the problem most sailboats have as a engine is an auxiliary source of power...


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## sailingdog

Jody-

I never said that Diesel fuel doesn't degrade... just that it isn't generally going to turn into varnish, like gasoline does. The declining quality of fuel, whether diesel or gasoline, has much more to do with the more volatile components evaporating off than anything else.

Gasoline has additional problems since the introduction of ethyl alcohol as the primary octane booster/oxygenator, since the ethanol will start to separate out once the water content reaches 1.5% by volume or so... making the remaining gasoline about 84 octane or so.

BTW, ethanol has replaced MTBE, which was the previous octane booster used in unleaded gasoline, but had some serious issues, since it was both a carcinogen and water-soluble IIRC. MTBE replaced tetra-ethyl lead, which was the most common octane scavenger up until the advent of the catalytic converter. The platinum catalyst in the catalytic converter is contaminated by lead, and the Clean Air Act of 1970's requirement of catalytic converters was a primary reason for leaded gasoline being phased out.

Diesel fuel is helped quite a bit by modern fuel stabilizers, and shouldn't be that much of an issue. The biggest problems with diesel fuel over long periods of time are condensation and the resulting growth of bacteria at the water-diesel interface. Modern fuel treatments help with both of these problems to some degree to, within reason.



artbyjody said:


> No I am not confused about my post. Owning a wide variety of powered contraptions... That rarely get used but always get up and go... However, I pay attention to the fuel... And FYI Diesel degrades.. while may not varnish will give varying declining return depending on volume and sit time... Which is the problem most sailboats have as a engine is an auxiliary source of power...


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## artbyjody

sailingdog said:


> Jody-
> 
> I never said that Diesel fuel doesn't degrade... just that it isn't generally going to turn into varnish, like gasoline does. The declining quality of fuel, whether diesel or gasoline, has much more to do with the more volatile components evaporating off than anything else.
> 
> Gasoline has additional problems since the introduction of ethyl alcohol as the primary octane booster/oxygenator, since the ethanol will start to separate out once the water content reaches 1.5% by volume or so... making the remaining gasoline about 84 octane or so.
> 
> BTW, ethanol has replaced MTBE, which was the previous octane booster used in unleaded gasoline, but had some serious issues, since it was both a carcinogen and water-soluble IIRC. MTBE replaced tetra-ethyl lead, which was the most common octane scavenger up until the advent of the catalytic converter. The platinum catalyst in the catalytic converter is contaminated by lead, and the Clean Air Act of 1970's requirement of catalytic converters was a primary reason for leaded gasoline being phased out.
> 
> Diesel fuel is helped quite a bit by modern fuel stabilizers, and shouldn't be that much of an issue. The biggest problems with diesel fuel over long periods of time are condensation and the resulting growth of bacteria at the water-diesel interface. Modern fuel treatments help with both of these problems to some degree to, within reason.


We actually do not disagree less that I felt you were trying to hit the finer points that I may have left out. Ironically with lead almost minimal in fuels a catalytic converter is still required... ironic? My original points I stand behind - having 5 vehicles, (one diesel)... plus the boats - I am more aware of the damage of bad fuel than most... also - more aware that one doesn't have to be overly energetic either... which was my point.. 20 years - semi regular maintenance and concentration on fuel quality goes a lot longer way than regularly doing every maintenance aspect and neglecting the fuel (which I think most do - considering when wintering - it sits for for six month or so and regardless if it is varnish or bio containments (diesel) - fuel is probably one of the top contributors to engine problems due to the nature of how sailboaters use the engines...


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## KeelHaulin

I tend to disagree on the "myth" that says a diesel engine will get glazed cylinders because it has idled too long. If it is running at proper temperature and is burning cleanly (proper fuel metering, clean injectors, clean fuel) there really should be no reason for it to leave enough un-burned fuel in the cylinders for it to build up. There are hundreds of thousands diesel trucks on the road that run at idle for hours while at truck stops; as well as tractors that sit idle between jobs, and they don't "glaze" while running at idle.

I think that under-loading the engine while motoring is a bigger problem. Most sailboats have undersized props to reduce drag and the hull form is easily driven for efficiency; so the engine never sees the loads that it should regularly get to keep it from getting carbon build-up, dirty injectors and valves. In addition the wet exhaust wears on the engine due to the salt vapour (while sitting dockside) and back pressure while running.

I suggest doing a few acceleration runs now up to max RPM now and then while motoring (when engine is fully warm). If you get black smoke puffing out at first; do it a few more times and it should clear. It is just carbon getting flushed out of the combustion chamber and exhaust.

Let your engine warm up when starting from cold; it is important to warm up the engine oil before putting it under load. I'd be more worried about bearing and cylinder wear while running the engine under load when cold than causing cylinders to glaze. I'd be willing to bet that most if not all diesel owners manuals recommend warming the engine before driving/revving.

On the issue of rebuild vs. replace; well that depends on what your plans are and if you can DIY. A rebuild is almost always cheaper if you do your own work. If your engine is only stubborn to start or has some other problem (smoking, rough idle, etc) it might be worth having a mechanic look at the engine and diagnose the problem before you drop big bucks on a new powerplant. Too often the problem is a simple repair and the engine is otherwise fine (but the owner thinks it is tired/worn out). Sometimes all that is needed is a cylinder head rebuild; or a new starter, injector cleaning, injector pump, etc. These are _maintenance items_ for a diesel engine; and should not be overlooked. Change your oil every 100 hours or 6 months; keep it topped up. Do the regular maintenance like pencil zincs, coolant, impeller, fuel filters, injector maintenance if needed, and your engine should last almost indefinitely.


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## sailingdog

Jody-

This statement shows you really don't understand what I am saying at all. *The catalytic converter is the REASON that we don't use leaded fuels any more. * The catalytic converter has nothing to do with octane boosting, and a lot to to with the content of the exhaust coming out of the tail pipe. It is one of the major components of a emissions control system on a modern gasoline engine. If you were to put leaded gasoline through a car equipped with a catalytic converter, the engine would burn it just fine... but the tetraethyl lead would destroy the catalyst in the catalytic converter-requiring you to replace it.


> Ironically with lead almost minimal in fuels a catalytic converter is still required... ironic?


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## hellosailor

SD-
Around the same time that folks were trying to clean up emissions and someone decided the catalytic converter was a good idea...Remember that we also got rid of leaded gasoline because LEAD IS AN ENVIRONMENTAL TOXIN and heavy lead levels were found in the blood of people living in heavy exhaust areas--as well as on/in the ground. Same thing for asbestos from brake pads, on ground.

We didn't just get rid of lead to make the catalysts happy, we switched to catalysts because getting rid of the lead was necessary, and synchronicitous (ouch) on the timing.

Of course, glomming onto MTBE and spreading that all over the ground water supply wasn't exactly a smart move, but it made so many ecofreaks SO very happy because it wasn't "ethyl". (sigh.) Now I'd just like to find someone who sells GASOLINE without the booze in it, in the car I'm sure I see a 10% mpg loss thanks to the booze, and even the EPA reluctantly confirms that. Let's see now...it burns 10% cleaner, but I need to burn 10% more of it....And that accomplishes, uh, what? Duh?

Short engine runs also contribute to engine wear because the oil has not been heated up high enough and long enough to "cook off" the condensates and the fuel that normally dilute the oil. If the typical auto engine isn't run for at least a 1/2 hour every time the car is used--the oil builds up excess levels of fuel and water (condensate) and the engine wears because the oil has been contaminated. Frequent oil changes don't really help that, because the contaminants build up so fast. A half hour at "operating temperatures" generally is enough to cook them off though. I caught on to this after some oil analysis left me asking "Why is my oil contaminated?" and I'm just mule-stubborn now about not hitting any ignition key without a Real Good Reason. Diesel, auto, no matter, same oiling system same problem. There's just more condensation in typical marine installations, so even more need to cook it off.


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## theartfuldodger

Two things black smoke is unburt fuel , and engine idling by trucks is not as it states, all trucks at idle have their rpms boosted to a higher rev to clean burn. Idling per say for highway rigs today is constanlty monitor by base stations company owned, for such reason as speeding over revs and idle time.


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## sailingdog

HS-

Well said...  BTW, if the auto industry hadn't been pushing the oil industry to remove the lead, we'd probably still be using leaded gasoline... I know, since I've seen some of the oil and auto industry memos on the issue.


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## KeelHaulin

theartfuldodger said:


> Two things black smoke is unburt fuel , and engine idling by trucks is not as it states, all trucks at idle have their rpms boosted to a higher rev to clean burn.


Black soot expelled while accellerating is not necessarily unburned fuel. I know this because my Perkins 4-108 was carboned up when I bought the boat. A few acceleration runs up to hull speed/3500 RPM expelled the crud. Now if I accelerate the boat I get nothing but normal exhaust. The engine did not have a problem starting beforehand. Diesels need to be put under a load and revved now and then to clear the combustion chamber; just as gasoline engines do.

If I am sitting idle or motorsailing to charge the batteries; I run at around 1100 RPM; base idle is 700 or so. At low RPM the alternator does not kick on; 100RPM is where it starts charging batteries. So if that's true regarding high idle to burn cleanly; I'm already doing that. I still don't think you are going to glaze your cylinders while warming up the engine for 15-20 minutes. If dockside I engage reverse to help warm up the gearbox for 5 minutes or so before exiting the slip.


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## danjarch

I would add to my original posts, that Valente and keelhauling both make good points to consider. You need to check how much other stuff may have to be moved or replaced to upgrade. If you have to have a new fuel tank custom made or a custom wet exaust it might be cost prohibative. Also if your able to do alot of the stuff your self, the cost of rebuilding will go down. One warning to remember. Any thing that wasn't suposed to go to the machine shop that was still attched. Will be handed back to you all in the same box with out any notes on where it came off.

For my money I would rebuild the engine, but that comes with a caviat. I would not only remove the engine myself, but other then having the block and head magnafluxed or pressure tested, plus maybe the cam or crank shafts milled, I would do most of the rebuild my self. So for me it would be a couple hundreds or so in parts, and taking the time to grind or sandblast and repaint the motor mounts, manifolds, and other bits.

In the end, before you make any firm decisions, have a couple estimates writen up for each option. Don't worry about wasting other people's time. I'm a home remodler now and it never bothers me to give estimates to people who really are considering hiring me. It only bugs me when there just fishing for lower prices then they've already been quoted or already plan to give the work to someone else and are just getting quotes for insurance.


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## Ilenart

*Thanks for all the posts.*

some got a bit off topic but hey thats how the discussion goes.

Hellosailor, hard or soft hours? Proper maintenance? Bit hard to tell as I've only owned the boat 2 years out of the last 29. Probably a mixed bag; the last owner kept detailed records & probably did a better job than me. The guy before him let the boat go downhill, which probably included the engine.

Valiente, my engine sounds similar to yours, low engine hours, no real problems but an elderly engine. I'm leaning towards your solution however I'm in no rush; I've got 2-3 years to see how the engine runs and make up my mind.

Sailingdog / artbyjody, understand your points about fuel problems. The previous owner had a theory that you never had to change the fuel filter until it clogged up as their are two inline and you switch to the 2nd one when necessary. When I checked the filter the main one was absolutely clogged with gunk and the taps were stuffed so fuel had always been run through both filters regardless whether the taps were opened or closed!

KeelHaulin, I normally run the engine at maximum revs of around 2,100RPM as thats pushing the boat around six knots and thats generally fast enough. The engine specs state maximum revs of 4,000rpm and continous maximum revs of 3,200RPM. I'll try your suggestion and take it up to 3,200 and see whether I get any black smoke.

Danjarch, should of mentioned that some things have already been repaired / replaced. For example, rebuilt starter motor by the previous owner, rebuilt saltwater pump & exhaust manifold by me, etc.

Probably should of also mentioned my plans are to coastal cruise for the next 3-5 years and then look at longer trips after that. Therefore I have the luxury of seeing how the engine performs whilst still fairly close to home. The rebuild / replace decision would be part of the preparation for the longer trips. So far the engine has performed faultlessly, starts no problem and chugs along no worries. Have always warmed up / cooled down, regularly changed oil, etc, etc.


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## Valiente

Ilenart said:


> Valiente, my engine sounds similar to yours, low engine hours, no real problems but an elderly engine. I'm leaning towards your solution however I'm in no rush; I've got 2-3 years to see how the engine runs and make up my mind.


Fair enough. If I wasn't going offshore, I wouldn't be doing a damn thing...but recreational use in Lake Ontario in which it's hard to be more than one day's sailing time from a rebuilder...is a different thing from even "coastal".

One thing you might consider now is to purchase the full set of rebuild parts now, as they will only be scarcer in three years when your engine is 32 years old. These days, if you discover after a diagnostic tear-down that your engine is still in great shape, you should have no problem flogging the parts on eBay or to some other rebuilder.

It's not that none of the parts will be available in three more years; it's that the one part you need won't be.

Having rebuilt an Atomic 4, a very popular engine that is frequently rebuilt, and yet having a few problems finding certain parts, I can imagine that for a rarer engine it would be significantly more problematic.


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## Haguesail

Another option is to exchange for a rebuilt engine of the same type, particularly if it is a common motor. I purchased a boat last year with a very tired MD11C and went through the same trade-off assessment. Replacing with a newer engine would provide more HP and lower weight, as well as piece of mind for $10k+. There are smaller shops offering rebuilt motors, generally ones they refurbished after taking out during a replacement. I ended up exchanging my MD11C for a rebuilt MD11C, helping with the work (a full day as there was no need to change mounts as when you re-engine), and now have a well-running motor for a bit over $3k. I would only do this with a reasonably local and reputable mechanic.

Chris 
Baltic 37 Brut
Volendam, NL


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## Rockter

Guys...

I will never understand this. 
The original posting has a 20 year old motor with 2700 hours on it and there is nothing wrong with it.
It starts, it runs, and the 'box is ok.
Some clash head says that 20 years means trouble when there is none and wants to sell a new motor that will not last 20 years because 20 years means trouble.

Get out of here.

Maintain it, and leave it there.

My old motor is 31 years old, and though it's not without trouble, at last count, it took me about 200 miles, used little oil, and started fine. I let it freeze a while back, and cracked the block. It weeps (out) a little, but it's raw cooled, so coolant supply is not a problem.

If it blows up I will change it, but the idea of tearing it out of there when I don't need to, I get from others wanting to sell me another one.



Rockter.


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## Valiente

Would you think differently if you were taking a child on a circumnavigation for five years? Mine "starts and runs and seems OK" but I know it's swallowed water (fresh at least) at some point because I'm the guy who fixed the buggered siphon break spring and did the kerosene flushes. I'm NOT the guy who did 20 winterizations (I've only done two) and therefore can't really know if they were done properly, or if the oil was changed religiously like I tend to do.

If I rebuild a basically sound engine, I gain information on the condition of the rods, bearings and journals thanks to some mechanic with a micrometer measuring wear. I also get brand new gaskets, rebuilt and calibrated injectors, a check on transmission wear, linkage adjustments, tappet and valve adjustments/replacements and a new pump and a heat exchanger to replace what will become old but functional spares. If the mechanic finds a rod with a hairline crack in it here, that's paid for the rebuild in peace of mind when I'm trying to claw off a reef shore three years hence in the Pacific somewhere several thousand miles from a Westerbeke distributor.

Plus a paint job. Did I mention the paint job?

The result is that I "restart the clock" from a known baseline and maintenance schedule, instead of dealing with the pluses or the minuses (both unknown) of two previous liveaboard owners, neither of whom seems to have used the engine much at all. When I had an Atomic 4 rebuilt in 2005 (I did part of the work myself), I had that new baseline, and that engine is absolutely perfect every day since...perfect compression, great spark, low idle RPM and the obvious benefit of predictable filter changes, oil changes, etc.

I am a believer in prophylaxis. That's the habit of fixing things, insofar as possible, before they are broken. It's the logic of virus scanning in computers, and of immunization in medicine. A rebuild prior to a known situation wherein I will be a) running several hundred hours per year, compared to several dozen, and b) far from easy access to parts and mechanics, and c) where having as perfect and reliable a diesel auxiliary as I can devise becomes a huge part of keeping my family safe during an extended cruise would seem to be prudent to me, at the least.

And prudence, as part of a general awareness that things go wrong on the ocean, is, to me, the better part of seamanship.


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## sailingdog

And these are both good for adding points to your black box account. 


Valiente said:


> ...I am a believer in prophylaxis. That's the habit of fixing things, insofar as possible, before they are broken....
> 
> And prudence, as part of a general awareness that things go wrong on the ocean, is, to me, the better part of seamanship.


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## Valiente

I should just paint the entire boat black, to acknowledge the fact...


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## sailingdog

If you're talking about the steel boat, you'd basically be regretting that...it'd be like a giant solar oven.  Especially, once you got down to the caribbean.


Valiente said:


> I should just paint the entire boat black, to acknowledge the fact...


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## Valiente

I was joking, although I do wear a black fedora sailing at times.


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## Rockter

Guys...

All of your counter-arguments are dependent on the new, or re-built motor being reliable. That's quite an assumption. The old one is, so you'll disturb it, it may not come apart easily, and you may well break something when you do.

The old motor IS reliable, and that's the reason why you would wish to leave it alone. If it is NOT reliable, then talk of long distance risks with children, or whatever.

This cheque-book mantra that a 20 year old engine must be suspect will, by definition, add a new motor to your boat cost every 20 years. Yes, $12,000... that's $600 a year to you Sir. Cue $12 a week, to "avoid" trouble. 

What works, leave it alone. Give it TLC, and leave it alone. It knows the game by 20 years... your boat, the loads, the prop, the environment, and how much oil it uses. You cast all of that to the four winds when you put a new one in there.... some even choose one with a turbo!!!!.... and you'd better hope it's as well-built as the last one.

Rockter.


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## Valiente

I and my bank account and my conscience would love to agree with you, R., really, I would. But the low-hours regimen and the annual winterizations (not a feature of Scotland so much, I think, even if there is frost on the loch occasionally) puts in too many variables for me to be comfortable with.

As I said, I believe that a rebuild in my situation will be primarily diagnostic...I may only require a ring job, new gaskets and rebuilt injectors to get microscopic amounts of crud out. But I've had the valve cover off, and there's the sort of corrosion you get from having a heated boat in cold water: condensation. Not to mention that there's been known backwashes of water into the block.

I could afford a new engine, but I like the simpler (read: heavy) technology of a 1980s diesel. That's why I'm rebuilding rather than replacing.

Thank you for your thoughts, however.


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## Dumah

I own a 135HP mermaid (Ford) and have found that through American Diesel the parts to rebuild a Leahman cost us approximately $ 2000 plus my labour. As I was the engineer in question that cost was not an issue. I guess my point is that depending on your particular make and application, the age of the carcass does not matter if your block is sound. These particular engines are relatively unchanged over 40 years and internal parts can be obtained from virtually any industrial distributor. My vessel is a converted Cape Island that fished for over 20 years and the the engine I have has less than 300 hours on the first rebuild. The attraction for me for these engines is the interchange with agricultural applications (I had to replace two rods and they came from a 4 cylinder tractor engine) and the marine parts can be mixed from other conversions easily and readily. I will freely admit that this is not a "modern" engine, but have found that they are an excellent value and seems to be no end of parts availability. I realize that you wind sailors don't need a monster like mine but it might be worth thinking domestic when considering a repower. Hope this further muddies the waters, good fortune and pleasant sailing;
Dumah


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## Dumah

Forgot to mention that the Leahman (108 HP) was originally built in 1964, and is still in service, pushing a 42' square chime trawler style hull @ 8.5 knots and burns .75 GPH. that rebuild cost us under $2000 including 2 power packs, truning the crank, and rebuilding the injector pump and replacing injectors with remans.
Dumah


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## chrisj13

I love the diesels, and would vote for rebuild. These things run forever, even under harsh conditions! Unless you are going to be thousands of miles from services, I like to repair things rather than replace. (Like to know the history, vs a brand new unknown item.)


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## bwindrope

Though I have no interest in joining or fanning some of the arguments here, I would like to add a story about my experiences in a relevant situation: 

When I was examining my current boat for purchase I noticed that the Universal 5432 diesel wasn't firing on the #1 cylinder. You could hold the injection line and clearly feel that it wasn't pulsing. The motor looked like it hadn't been cleaned or maintained, and the owner was clearly unaware of a good maintenance schedule. On the test run the boat would not come up to it's rated cruising RPM of 2200 and ran at a very cold 160 degrees for a fresh water cooled diesel. This raises serious concerns about the combustion of the engine and the carbon build up from running so cold. 

As it was not my job to diagnose his diesel problems, but to buy the boat, I negotiated the price down a full $10,000 on the belief that I would have to replace the diesel. He had every reason in his mind to believe the diesel was in need of at least a major overhaul, if not replacement. 

I suspected otherwise, but it wasn't my job to tell him. After purchasing the boat, I immediately pulled the injectors and took them to a great diesel repair shop where they told me they were in perfect condition mechanically and were simply gummed up with carbon and needed cleaning. 

That solved the #1 cylinder problem. When I hauled the boat out, I saw that the prop was a 3 blade 16X12 and research told me that for my boat and that engine a 15X10 would be a better fit. Had the prop re-pitched and she reached hull speed easily in flat water at her rated cruising RPM of 2200. 

I then replaced the thermostat with a 190 degree version and she ran at a steady 185 in our cold NW waters. 

The outcome of all this? I have a 25 year old diesel in my boat that has 800 total hours and is in superbly good shape, uses .68 gallons an hour average over 100 hours, burns completely clean, uses no oil, and has no leaks. The previous owner thought it was trashed and needed rebuilt or replaced. 

The cost of everything I did to put it into excellent shape? Something less than $250, and most of that was for the prop repitch. I've done many other preventative maintenance tasks since then, but nothing near a boat "unit". 

If there is a point to this story, it is just that there are a great many variables with engines, and that it is entirely possible to salvage a seemingly dead diesel if the owner becomes aware of basic repair and maintenance. 

I wish all of us luck with our motors...


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